Dr. Jeff Masters' WunderBlog

Tropical outlook for July

By: JeffMasters, 2:06 PM GMT on June 30, 2006

A new area of disturbed weather has formed in the extreme southwestern Gulf of Mexico, near the coast of Mexico. The thunderstorm activity has little organization, and strong upper-level winds from the west are creating 15-25 knots of wind shear over the system. Wind shear is expected to remain 15 knots or higher for at least the next two days, making it unlikely for this disturbance to develop. The disturbance will move slowly northwest and bring welcome heavy rains to South Texas and Northeast Mexico over the weekend. Extreme drought conditions prevail there, but flash flooding may be a concern nevertheless.


Figure 1. Model forecast tracks of the tropical disturbance in the Gulf of Mexico.

Tropical wave in the Caribbean and Bahamas
The tropical wave in the eastern Caribbean we've been watching this week is just barely visible as a line of showers moving across Hispaniola towards Cuba and the Bahama Islands. Strong upper-level winds should continue to prohibit development of this wave over the Caribbean. However, the northern portion of this wave, now located north of Hispanolia and the easternmost Bahama Islands, is kicking up an impressive area of deep thunderstorms this morning. Wind shear is a high 20 knots over this disurbance, but the disturbance is moving northwest towards an area of lower wind shear. This may allow for some slow organization today before increased wind shear over the weekend tears this system apart. The disturbance is not a threat to land, as it is expected to recurve to the north and northeast around the Bermuda High.

Are we due for a repeat of the Hurricane Season of 2005?
That's the question on everyone's minds as we hit the end of the first month of hurricane season. After all, we've already had one tropical storm (Alberto) that occurred about the same time as last year's first storm (Arlene), and we almost had a second tropical storm near North Carolina this week, which would have made June 2006 match the June 2005 total of two tropical storms. Let's take a look at the large-scale weather patterns over the Atlantic and compare June 2005 with June 2006.

A look at June 2005
In Figure 2, we see the sea surface temperature (SST) and surface pressure departure from normal for June 2005. June SSTs were 1-2 C above normal, and June pressures were much below normal over almost the entire North Atlantic. The pressure at the center of the Bermuda High was 5 mb below normal, and pressures over the Caribbean and tropical Atlantic were about 1 mb below normal. The force of the trade winds that blow across the ocean is governed by the pressure gradient between the center of the Bermuda High and the tropics. The greater the difference in pressure, the stronger the winds have to blow, in their effort to equalize the pressure. In June 2005, this pressure gradient was very weak, and thus the trade winds were much lighter than usual. Lighter winds meant less evaporation occured over the surface waters, and thus less evaporative cooling (loss of latent heat). Without the usual strong winds to cool the ocean, the waters were able to heat up to record warm levels.

A ridge of high pressure dominated the Eastern U.S. in June 2005, and this ridge of high pressure continued to dominate throughout the entire hurricane season. As a result, the jet stream stayed far to the north, keeping wind shear low over the Gulf of Mexico and Caribbean. This ridge also acted to steer hurricanes into the Gulf Coast.


Figure 2. Sea Surface Temperature departure from normal for June 2005 (left) and surface pressure departure from normal (right). The arrows show the departure of surface winds from normal. The Bermuda High had a central pressure 5 mb lower than normal, which meant that the winds circulating around the high were weaker than normal. Thus, the surface wind anomaly arrows plotted above appear to rotate counterclockwise around the Bermuda High. Image credit: "The 2005 hurricane season: An echo of the past or a harbinger of the future?" Geophysical Research Letters, 33, March 2006.

A look at June 2006
An opposite trend in surface pressures occurred in June 2006, compared to June 2005 (Figure 3). The Bermuda High has averaged 7 mb stronger than normal this month--and a full 12 mb stronger than last year's June Bermuda High. Low pressure has dominated the Eastern U.S., thanks to a persistent dip in the jet stream that has brought rain, floods, and relatively cool weather to the Eastern U.S. This dip in the jet stream has also brought much higher levels of wind shear to the Gulf of Mexico and Caribbean than we saw last year in June.


Figure 3. Surface pressure departure from normal for June 2006. Note that surface pressures at the center of the Bermuda High were 7 mb above normal, and that pressures along the East Coast of the U.S. were below normal. Image credit: NOAA Climate Prediction Center.

As a result of the stronger Bermuda High this June, the trade winds blowing across the tropical Atlantic are much stronger than they were last year in June. These stronger winds have cooled the ocean, and SSTs are only 0.5 - 1.0 degrees C warmer than average this June, compared to 1 -2 degrees above normal in June 2005. This year's SST anomaly is still quite high, but probably not enough to support major hurricanes in July, like we saw last year with Dennis and Emily.


Figure 4. Sea surface temperatures and departures from normal (anomalies) for June 2006. SSTs are still 0.5 - 1 degrees C above normal over the tropical Atlantic, but still a full degree cooler than 2005. Image credit: NOAA Climate Prediction Center.

Outlook for July 2006
The two-week forecast from the GFS model continues to show the jet stream dipping over the Eastern U.S., and a stronger than normal Bermuda High. This pattern favors a continuation of the cool, rainy weather over the Northeast U.S., and hurricane strikes on Florida and the East Coast of the U.S.--or recurvature out to sea. The Gulf Coast has lower than average odds of a strike. This jet stream pattern should act to keep wind shear high over the main breeding grounds for July tropical cyclones--the Gulf of Mexico, Bahamas, and western Caribbean. If a hurricane does manage to develop and dodge the shear, it is unlikely it will become a major hurricane, due to the relatively cool ocean waters expected this July, compared to July 2005. Thus, July 2006 will not be a repeat of July 2005, which had five named storms, three hurricanes, and two intense hurricanes. If the current upper-level jet stream pattern holds in place, I think we can expect one or two named storms in July, one of them being a hurricane (not major). Will the current jet stream pattern hold? We are not very good at anticipating when these "blocking patterns" in the large scale atmospheric flow will change. Sometimes they can last for an entire season. If the pattern breaks in the last half of July, we could see more activity than I am forecasting here. In any case, I am still anticipating that August and September will be very busy again this year, so enjoy the relatively quiet start to hurricane season!

Have a great 4th of July weekend everyone, and I'll be posting daily updates.

Jeff Masters

Updated: 4:09 PM GMT on June 30, 2006

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Flood walls hold on the Susquehanna

By: JeffMasters, 12:09 PM GMT on June 29, 2006

The Army Corps of Engineers is breathing a sigh of relief today. After the failure of New Orleans' levees during Hurricane Katrina revealed that the Army Corps had failed to properly construct those structures, they must have been very anxiously watching the flood walls restraining the rampaging Susquehanna River in Wilkes-Barre, PA yesterday. The new flood walls, built in response to the record flooding from Hurricane Agnes in 1972, were built 3-5 feet higher at a cost of $200 million. The new walls took 20 years to build, and were completed in 2003. Do to the uncertainty of how long the new walls could hold back such a large volume of water, over 100,000 people were evacuated yesterday from the Susquehanna's flood plain. The Susquehanna crested late Wednesday at 34.4 feet, just six feet below the tops of the new flood walls, and 16 feet above flood stage. The river is slowly declining, and was at 32 feet this morning at 4 am EDT.


Figure 1. Measured rainfall from the week's rains. Tropical moisture streaming north along a stationary trough of low pressure triggered rains as heavy as 3 inches per hour in the mountains of Pennsylvania.

Hurricane Agnes of June 1972 did $8.6 billion in damage to Pennsylvania and surrounding areas. Agnes at the time was the costliest hurricane in history, a distinction it held for 20 years--when Hurricane Andrew came along. Thanks to the recent spate of intense hurricanes hitting the U.S., Agnes has fallen to number nine on the list of costliest hurricanes of all time. Six of the nine costliest hurricanes of all time occurred in the past two years!

Tropical wave in the Caribbean
A strong tropical wave moved through the Windward Islands yesterday, bringing heavy rain and wind gusts up to 36 mph. Strong upper-level winds from the west severely disrupted the wave overnight. This wind shear of 20-30 knots is expected to continue, and no development is likely today. The wave is expected to bring thunderstorms and gusty winds to Puerto Rico and Hispanolia as it moves west-northwest at 20 mph. The wave could get more organized once it gets closer to the U.S., if it can find an area of lower wind shear to take advantage of. The prospects of this happening are low, as most of the ocean areas surrounding the U.S. are expected to have high wind shear over the coming week. None of the computer models develop this wave, and there is really nothing anywhere in the Atlantic that looks to be of concern over the next few days.


Figure 2.Latest satellite image of the tropical wave in the Caribbean.


Figure 3. Model forecast tracks of the tropical wave in the Caribbean.

Thanks to all of you who tuned into my "Tropical Round Table" interview last night on http://radio.nhcwx.com/. I'll be summarizing much of what I said in tomorrow's blog. In particular, I'll focus on how different the large-scale atmospheric patterns for this year's hurricane season are compared to last year's season. This year will not be a repeat of 2005!

Jeff Masters

Flood

Updated: 7:05 PM GMT on June 29, 2006

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Tropical update

By: JeffMasters, 12:44 PM GMT on June 28, 2006

The low pressure system that almost became Tropical Storm Beryl yesterday churned up the East Coast last night, bringing heavy rain, high winds, and coastal flooding to the Mid-Atlantic coast. Winds gusts as high as 52 mph were recorded in Dover, Delaware early this morning, and tides of 1-3 feet above normal were seen all along the coast. The additional rain was unwelcome for Maryland, which has seen over a foot of rain in some areas over the past week. In suburban Washington D.C., 500 people were evacuated this morning due to the possible failure of the Lake Needwood dam on the north side of Rockville.


Figure 1. Estimated rainfall from the week's rains have exceeded one foot in some areas of Maryland.

Tropical wave approaching the Windward Islands
A tropical wave approaching the Windward Islands has become less organized since yesterday. Wind shear has increased from 10 knots yesterday to 25 knots today, and a surface circulation is no longer evident on visible satellite imagery. The wave will bring heavy rain and gusty winds to Barbados this afternoon and most of the remainder of the Windward islands tonight, as it moves west-northwest at 20 mph. The wave does have the potential for some slow re-organization over the next two days, as the GFS computer model is indicating that an area of lower wind shear may develop over the wave. However, high wind shear is forecast to dominate most of the Caribbean and tropical Atlantic over the coming week, and it will be difficult for tropical storm formation to occur during this period. Only the Canadian model is forecasting that this tropical wave will develop into a tropical storm, and this model has been overdeveloping many tropical systems this June.


Figure 2.Latest satellite image of the tropical wave approaching the Windward Islands.


Figure 3. Model forecast tracks of the tropical wave approaching the Windward Islands.

Tonight's interview on Internet radio
Tonight starting at 9:30 pm EDT, I'll be the guest on Tropical Round Table, a live streaming audio show hosted by http://radio.nhcwx.com/. I'll be answering questions from the host, Mike Naso, for about 20 minutes. The show starts at 9 pm and runs for an hour.

Jeff Masters

Updated: 3:45 PM GMT on June 28, 2006

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Hurricane Hunters don't find a Beryl

By: JeffMasters, 7:09 PM GMT on June 27, 2006

The National Hurricane Center put out the following statement summarizing what the Hurricane Hunters found this afternoon in the area of disturbed weather near Morehead City, NC:

Special tropical disturbance statement
228 PM EDT Tue Jun 27 2006

Recent information from an Air Force Reserve reconnaissance aircraft indicates the area of disturbed weather is centered about 35 miles southwest of Cape Lookout North Carolina. While there is a small area of gale force winds on its east side... the system does not have a closed surface circulation... and is therefore not a tropical cyclone at this time. The aircraft will continue to investigate the system this afternoon.

There is still the potential for this system to develop into a tropical storm as it moves north to north-northeastward at 20 to 25 mph. Residents in coastal regions of North Carolina... Virginia...and the Delmarva Peninsula should closely monitor the progress of this system today as tropical storm warnings could be required with little notice. Even if this system does not form into a tropical cyclone... it will produce showers and thunderstorms with locally heavy rainfall and strong gusty winds across the mid-Atlantic area today and tonight.



Figure 1. Current Morehead City radar.

While Doppler radar showed that this system did have a circulation at mid-levels of the atmosphere and winds high enough to be classified as a tropical depression, the circulation never made it down to the surface. The center of the storm came onshore near Morehead City at 3:30pm, so this system is all done with, as far as potential to become Tropical Storm Beryl goes. The storm will bring heavy rain to coastal North Carolina tonight. Already, radar estimated rainfall in some narrow bands near Morehead City exceed four inches (Figure 2.) Rainfall rates of up to .5 inches/hours are occurring in some of the heavy rainbands moving onshore. Coastal Virginia and Maryland should see rains of at least 1-3 inches from this system on Wednesday, but the bulk of the rain should stay east of Washington D.C., which has suffered extensive flooding the past few days.


Figure 2. Current radar-estimated rainfall for North Carolina.

Disturbance east of the Windward Islands looking healthier
A tropical disturbance about 500 miles east of the southern Windward Islands is tracking west-northwest at 20 mph. This system does have a surface circulation one can see on visible satellite imagery. Heavy thunderstorm activity on the east side of the center of circulation has become more concentrated this afternoon; wind shear from the west is keeping thunderstorm activity from building on the west side of the center. Wind shear has dropped considerably today, from 20 knots to 10 knots, and the latest computer model forecasts indicate that wind shear may remain low for the next two days, allowing some further slow organization. The system will bring gusty winds and heavy rain showers to the Lesser Antilles Islands on Wednesday. Later in week, the computer models are indicating that the disturbance may encounter a region of high wind shear that will make it difficult for the system to survive.


Figure 3. Preliminary model tracks for the disturbance east of the Windward Islands.

Jeff Masters

Updated: 7:41 PM GMT on June 27, 2006

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Tropical depression forming near North Carolina?

By: JeffMasters, 12:00 PM GMT on June 27, 2006

Satellite and radar data from the past few hours indicate that a tropical depression may be forming about 140 miles south of Cape Fear, North Carolina. This system is moving north to north-northeast at 15-20 mph, and will bring high winds and heavy rain to coastal North Carolina late this afternoon and tonight. Tropical storm warnings may be issued for portions of the North Carolina coast early this afternoon, after the Hurricane Hunters have had a chance to check out the system. An airplane is scheduled to arrive at the storm around noon EDT today.

Here's the special advisory put out by NHC at 7:30am EDT:

Special tropical disturbance statement
730 am EDT Tue Jun 27 2006

Satellite and radar information indicate that a small low pressure system could be forming about 140 miles south of Cape Fear North Carolina. This system has the potential to develop into a tropical depression at any time as it moves north to north-northeastward at 15 to 20 mph. An Air Force Reserve reconnaisance aircraft will investigate the system later this morning to determine if a closed circulation exists at the surface.

Residents along the North Carolina coast should closely monitor the progress of this system today as tropical storm warnings could be required with little notice. Even if this system does not form into a tropical cyclone... showers and thunderstorms accompanied by locally heavy rainfall and strong gusty winds will gradually spread onshore the North Carolina coast today and early tonight.


The Long range radar loop out of Wilmington, NC shows an extensive area of heavy rain off the coast, and some spiral banding starting to form. Wind shear is low, the waters beneath are warm, and conditions appear favorable for a tropical depression to form. The system only has about 6-10 hours over water before it comes ashore, so it is unlikely we will get more than a 45 mph tropical storm. Heavy rain will be the main threat from this system, and regions of coastal North Carolina near and to the right of where the center comes ashore can expect 4-6 inches of rain over the next day. Coastal Virginia and Maryland should see rains of at least 1-3 inches from this system on Wednesday, but the bulk of the rain should stay east of Washington D.C., which has suffered extensive flooding the past few days.


Figure 1. Current radar from North Carolina.

Disturbance east of the Windward Islands
A tropical wave about 800 miles east-southeast of the southern Windward Islands is tracking west-northwest at 15 mph. The heavy thunderstorm activity surrounding this system is being sheared by strong upper level winds. This system is moving towards an area of higher wind shear, and is not expected to develop.


Figure 2. Preliminary model tracks for the disturbance east of the Windward Islands.

I'll be back with up update early this afternoon after the Hurricane Hunters arrive at the North Carolina storm.

Jeff Masters

Updated: 12:15 PM GMT on June 27, 2006

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Carolinas need to watch out Tuesday

By: JeffMasters, 7:58 PM GMT on June 26, 2006

The low pressure system we've been watching the past week over the Bahamas moved inland over central Florida yesterday, and is not a threat to develop into a tropical storm today. However, thunderstorm activity has increased over the Bahamas and Gulf Stream to the east of Florida today, and the latest 8am EDT run of the GFDL model is predicting that a tropical storm will form off the Florida coast on Tuesday morning. This storm is forecast to move rapidly northward and hit near the South Carolina/North Carolina border on Tuesday afternoon. If this occurs, all of coastal North Carolina is in for some very heavy rains Tuesday night through Wednesday. Most of the development should be on the east side of the storm, so South Carolina will not get hit as hard. The other models are not as enthusiastic as the GFDL about such a storm developing, and it certainly doesn't have much time to get it's act together. I think a tropical depression is quite possible, however. Regardless, this low pressure system will bring heavy rain and gusty winds to the Southeast U.S. over the next two days. Depending on the low's track, the mid-Atlantic coast may also get a good soaking on Wednesday. The Hurricane Center has a Hurricane Hunter aircraft ready to investigate anything that might pop up Tuesday.


Figure 1. Preliminary model tracks for the low over Florida.

Disturbance east of the Windward Islands
A weak low pressure area near 7N 48W, about 1000 miles east-southeast of the southern Windward Islands, is tracking west-northwest at 15 mph. The heavy thunderstorm activity surrounding this low has mostly dissipated this afternoon. This low is moving west towards an area of higher wind shear, and is not expected to develop.


Figure 2. Preliminary model tracks for the low east of the Windward Islands.

I'll be back with up update on Tuesday.

Jeff Masters

Updated: 8:04 PM GMT on June 26, 2006

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A quiet Monday in the tropics

By: JeffMasters, 1:23 PM GMT on June 26, 2006

The tropics are quiet again today. The low pressure system we've been watching the past week over the Bahamas moved inland over central Florida yesterday, and is not a threat to develop into a tropical storm today. However, if the center of this system can emerge over water, we might get some development. Some models are indicating the possibility of a center of circulation forming south of the Carolinas on Tuesday, then tracking northward. The Hurricane Center has a Hurricane Hunter aircraft ready to investigate anything that might pop up Tuesday. Regardless, this low pressure system will bring heavy rain and gusty winds to Florida and the Southeast U.S. over the next two days.


Figure 1. Preliminary model tracks for the low over Florida.

The well-defined area of low pressure far out in the Atlantic about 550 miles east-northeast of Bermuda we were watching over the weekend lost all its deep thunderstorm activity, and is also no longer worthy of discussion. The system that was forecast to develop north of Puerto Rico on Tuesday is now no longer being forecast to develop by the models. Wind shear is forecast to be quite high in this region over the coming week. In fact, wind shear is quite high over the entire Main Development Region (MDR) for hurricanes right now, as seen in the GFS model's wind shear forecast for 8 pm EDT tonight (00Z 27 June) plotted in Figure 2.


Figure 2. Forecast wind shear between 200 mb and 850 mb for 8pm EDT tonight. 850 mb is the typical pressure at about 5,000 feet in altitude, and 200 mb is the pressure at about 40,000 feet in altitude. The difference in wind speed between these two altitudes is a usually a good measure of the wind shear that affects tropical storm formation. Wind shear values less than 16 knots (8 m/s, the lightest two red colors) are typically needed for tropical storm formation.

New threat area east of the Windward Islands
A new area worth watching has cropped up near 7N 47W, about 1050 miles east-southeast of the southern Windward Islands. There is some heavy thunderstorm activity here and a 1012 mb low pressure area has developed. This low is moving west towards an area of higher wind shear, and is not expected to develop. Wind shear over most of the Atlantic is expected to remain seasonably high over the next week, making it difficult for tropical storm formation.


Figure 3. Preliminary model tracks for the low east of the Windward Islands.

I'll be back with up update on Tuesday.

Jeff Masters

Updated: 7:33 PM GMT on June 26, 2006

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A quiet Sunday in the tropics

By: JeffMasters, 3:10 PM GMT on June 25, 2006

The tropics are quieter today, with the three systems we discussed yesterday all looking less interesting.

Firstly, the low pressure system we've been watching all week over the Bahamas is now just off the coast of central Florida. The low is now tracking north-northwestward, parallel to the coast, and should reach Georgia/South Carolina on Monday. The counter-clockwise spin of the low has sucked in dry air into its center, putting a damper on any development for today. It is possible on Monday that the dry air may dilute enough to allow some development to occur. However, this is unlikely if the center of the low--which is right on the coast--moves inland.


Figure 1. Preliminary model tracks for the Florida low.

Low 550 miles east of Bermuda
A second area to watch is a well-defined area of low pressure far out in the Atlantic at 35N 54W, about 550 miles east-northeast of Bermuda. The deep thunderstorm activity surrounding the low has diminished since yesterday, thanks to an increase in wind shear. Sea surface temperatures (SSTs) are in the 23-25 C range, which is below the 26 C threshhold usually needed for tropical storm formation. This low reminds me of the "Greek" storms Delta, Epsilon, and Zeta that formed in a similar location with similar SSTs last Fall. Today's storm may be able to spend enough time the next few days over waters just warm enough to allow it to make the transition to a subtropical storm and perhaps even a tropical storm. More probably, it will not develop. The SSTs are probably too cold and there is too much wind shear around. The system is not a threat to land right now, and will track westward at 10 - 15 mph towards Bermuda over the next few days. None of the computer models are forecasting this low to develop into a tropical storm.

Forecasted development north of Puerto Rico
Most of the global computer forecast models have been consistently forecasting a tropical or non-tropical storm to form northeast of Puerto Rico on Tuesday or Wednesday. Today is the fourth day in a row the models been making this forecast, but the model runs the past two days have been decidedly less bullish about developing such a system. I remain dubious that storm will develop in this region, since there is a lot of wind shear in the vicinity. If a storm does form here, it is forecast to move northward towards Bermuda or northwestward toward the Southeast U.S. coast. SSTs are in the 26 - 28 C range in the area, which is warm enough to support a tropical storm.

I'll be back with up update on Monday.

Jeff Masters

Updated: 2:05 AM GMT on June 26, 2006

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Three tropical systems to watch

By: JeffMasters, 4:27 PM GMT on June 24, 2006

The tropics are getting more interesting today, with three systems to discuss. None of these systems poses a significant threat to any land areas, with the possible exception of Bermuda, for the last system I'll discuss.

Firstly, the low pressure system northeast of the Bahama Islands remains very disorganized today. The dry air to its west has been inhibiting its growth, despite the presence of relatively modest wind shear of 5 - 10 knots overhead. The wind shear is coming from the west, which is driving the dry air over Florida into the heart of the storm's circulation. If the wind shear had been from the opposite direction, where there is less dry air, the storm would have had a better chance of coming together. The system appears as a blob of clouds with just a few areas of deep thunderstorms, rotating about a broad and ill-defined center.


Figure 1. Preliminary model tracks for the Bahamas blob.

The Hurricane Hunter aircraft scheduled to investigate the system today has been cancelled, but is scheduled to fly on Sunday if needed. The system still has the potential to organize into a tropical depression, but its window of opportunity it getting short. The system should make landfall by Sunday or Monday along the northern Florida, Georgia, or South Carolina coast and dissipate inland. The dry air will continue to be a problem for the storm today, but may get diluted enough Sunday to allow some organization to occur.


Figure 2. Visible satellite image of the three tropical disurbances to watch today.

Low 800 miles east of Bermuda
A second area to watch is a well-defined area of low pressure far out in the Atlantic at 34N 51W, about 800 miles east of Bermuda. There is deep thunderstorm activty completely surrounding the low, and QuikScat satellite wind estimates showed winds near tropical depression strength--in the 20 - 30 mph range--at 4:30 am EDT this morning. However, sea surface temperatures (SSTs) are in the 23-25 C range, which is below the 26 C threshhold usually needed for tropical storm formation. This low reminds me of the "Greek" storms Delta, Epsilon, and Zeta that formed in a similar location with similar SSTs last Fall. Today's storm may be able to spend enough time the next few days over waters just warm enough to allow it to make the transition to a subtropical storm and perhaps even a tropical storm. The system is not a threat to land right now, and will track westward towards Bermuda over the next few days.


Figure 3. Preliminary model tracks for the low 800 miles east of Bermuda.

Forecasted development north of Puerto Rico
Most of the global computer forecast models--with the notable exception of the UKMET model--have been consistently forecasting a tropical or non-tropical storm to form northeast of Puerto Rico on Tuesday or Wednesday. Today is the third day in a row the models been making this forecast, so I thought I'd finally mention it, despite my doubts about the liklihood of this happening. There is a lot of wind shear forecast to be in the vicinity of the forecasted low, so it may have a difficult time organizing into a tropical storm. If a storm does form here, it is forecast to move northward and threaten Bermuda late next week. SSTs are in the 26 - 28 C range in the area, which is warm enough to support a tropical storm.

I'll be back with up update on Sunday, unless there is a major development to discuss.

Jeff Masters

Updated: 10:00 PM GMT on June 24, 2006

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Bahamas low growing slowly

By: JeffMasters, 4:06 PM GMT on June 23, 2006

A non-tropical low pressure system just northeast of the Bahama Islands has a surface circulation, and is expected to slowly grow more organized as it moves west-northwest towards Florida and the Carolinas over the next two days. Wind shear over the low was 10 - 25 knots early this morning at 5am EDT, but the 8 am EDT wind shear analysis from the University of Wisconsin's CIMSS showed that this shear dropped to 5 - 15 knots. The shear has continued to drop this afternoon, and was 5 - 10 knots at 2pm EDT (18 GMT). This should allow some modest development, and the Hurricane Center has scheduled a Hurricane Hunter aircraft to investigate the system on Saturday.


Figure 1. Preliminary model tracks for the Bahamas disturbance.

The low is very disorganized at present, with only a little intense thunderstorm activity near the circulation center. A QuikScat satellite wind estimate from 6:38 am EDT this morning revealed winds of about 15 - 20 mph in most of the region, with one tiny spot of higher winds in an intense thunderstorm near 23N 72W. Sea surface temperatures are in the 27 - 29 C range, which is well above the 26 C threshhold needed for tropical storm formation. However, as one can see from the water vapor satellite image below, there is a large area of very dry air over Florida. Upper level winds from the west are pushing this dry air into the center of the low, and this is inhibiting development. The low is forecast to move over Florida by Sunday, where it should bring welcome rains. It is also possible the low could turn northwest before reaching Florida, and move ashore over South Carolina or Georgia. Given the low's current poor organization, short amount of time it has to grow, and the presence of dry air and modest wind shear, the strongest system we can expect at landfall would be a 50-mph tropical storm. I think landfall as a tropical depression or a near-tropical depression is more likely.


Figure 1. Latest water vapor satellite image shows a very dry airmass (brown colors) over Florida, extending eastward into the Bahamas. The area of clouds northeast of the Bahamas at the edge of this dry air is what we are watching.

Hurricane-resistant homes
An interesting article from the New York Times yesterday described new super-strong homes being built in Florida and on the Gulf Coast. Insurers love them, and are offering up to 25% discounts on policies. With the high levels of hurricane activity observed since 1995 expected to continue at least another 10-20 years, expect to see this trend continue. I'd certainly be in the market for one if I lived in Florida!

I'll be back with an update later today if there is a significant change in the Bahamas system. I'll save my discussion of the large-scale weather pattern over the Atlantic so far this June for later.

Jeff Masters

Updated: 8:40 PM GMT on June 23, 2006

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Bahamas low slow to grow

By: JeffMasters, 1:23 PM GMT on June 23, 2006

A non-tropical low pressure system just northeast of the Bahama Islands now has a surface circulation, and is expected to slowly grow more organized as it moves west-northwest towards Florida over the next two days. A QuikScat satellite wind estimate from 6:38 am EDT this morning revealed winds of about 15 - 20 mph in most of the region, with one tiny spot of higher winds in an intense thunderstorm near 23N 72W. Wind shear over the disturbance has remained in the 10 - 25 knot range, which is keeping the deep thunderstorm activity to the east of the exposed circulation center. The wind shear is forecast to decrease by about 5 knots over the next day, which may allow thunderstorm activity to build in closer to the center. However, as one can see from the water vapor satellite image below, there is a large area of very dry air over Florida. This dry air is significantly inhibiting thunderstorms from building on the west side of the low. The dry air isn't going away, and the combination of the dry air and moderate wind shear will probably conspire to keep the low from becoming a full-fledged tropical depression. The low is forecast to move over Florida by Sunday, where it should bring welcome rains. A trough of low pressure swinging down from Canada should then pick up the low and move it northwards.


Figure 1. Latest water vapor satellite image shows a very dry airmass (brown colors) over Florida, extending eastward into the Bahamas. The area of clouds at the edge of this dry air is what we are watching.

Hurricane-resistant homes
An interesting article from the New York Times yesterday described new super-strong homes being built in Florida and on the Gulf Coast. Insurers love them, and are offering up to 25% discounts on policies. With the high levels of hurricane activity observed since 1995 expected to continue at least another 10-20 years, expect to see this trend continue. I'd certainly be in the market for one if I lived in Florida!

I'll be back with an update later today if there is a significant change in the Bahamas system. I'll save my discussion of the large-scale weather pattern over the Atlantic so far this June for later.

Jeff Masters

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Bahamas tropical disturbance

By: JeffMasters, 1:00 PM GMT on June 22, 2006

The area of disturbed weather between the Bahama Islands and Bermuda associated with a non-tropical low pressure system remains disorganized today. The amount of deep thunderstorm activity has actually decreased since yesterday afternoon, despite a drop in wind shear from 15 - 25 knots to 10 - 20 knots. There is some hint of a circulation at mid levels of the atmosphere in this morning's visible satellite imagery, but no obvious circulation at the surface. This disturbance still has the potential to develop into a tropical depression later this week. There is still a lot of wind shear for the disturbance to overcome, and none of the global computer models are developing it into a tropical depression. Any system that might develop would likely be steered into northern Florida, Georgia, or South Carolina by early next week.


Figure 1. An area of disturbed weather between the Bahamas and Bermuda bears watching the next few days.

Elsewhere in the tropics, there is no activity worth reporting. Some of the computer models are forecasting that a tropical storm could form north of Puerto Rico early next week, but this is unlikely, since wind shear is expected to remain very high over almost all of the tropical Atlantic Ocean for the next week.

I'll be back with an update on Friday, unless there is a dramatic change. I'll take a look on Friday at the large scale weather patterns over the Atlantic the past few weeks, which have led to a significant reduction in sea surface temperatures compared to last year at this time--good news for those of you in Hurricane Alley!

Jeff Masters

Updated: 12:32 AM GMT on June 23, 2006

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Climate change consensus study examined

By: JeffMasters, 2:08 PM GMT on June 21, 2006

I've had several people ask about the study Al Gore talked about in his movie, which found no scientific papers disputing the reality of human-caused climate change over the past ten years. Well, to be sure, there have been a few papers disputing the reality of human-caused climate change published in the past ten years, but they didn't happen to have the key words "global climate change" included in their citations. The study Gore cites was published in December 2004 in Science magazine by Naomi Oreskes, a professor at UC San Diego. The article examined peer-reviewed studies in the world's major scientific journals between 1993 and 2003 containing the phrase "global climate change" as keywords. Oreskes found that 75% of the 928 articles with those key words in their citations agreed with the consensus position stated by the UN's panel on climate change, that the observed global warming over the past 50 years has been caused in part by human activity. The other 25% of the papers took no position, and none of the papers disagreed with the consensus view. While the study is not a perfect measure of the scientific uncertainty in the published literature, the study does show that an overwhelming majority of published scientific research supports the idea that human activity is significantly modifying Earth's climate.

As Gore noted in his movie, the situation is quite different in the media, where about half of the stories in the study he cited cast doubt on the reality of human-caused climate change. The media are fond of trying to report both sides of an issue, so in the name of journalistic fairness, the public is receiving a highly skewed view of the scientific debate on climate change. In many cases, the opposing views presented by the media are from fossil fuel industry-funded "think tanks" that routinely put out distorted and misleading science intended to confuse the public.

I've collected a list of climate change position papers put out by the major governmental scientific institutes of the world that deal with the atmosphere, ocean, and climate. All of these organizations agree that significant human-caused climate change is occurring:

United Nations IPCC
American Meteorological Society
NOAA
U.S. National Academy of Sciences
NASA
EPA
American Geophysical Union
National Center for Atmospheric Research
Royal Society of the United Kingdom
Canadian Meteorological and Oceanographic Society

Science Council of Japan, Russian Academy of Science, Brazilian Academy of Sciences, Royal Society of Canada, Chinese Academy of Sciences, French Academy of Sciences, German Academy of Natural Scientists Leopoldina, Indian National Science Academy, Accademia Nazionale dei Lincei (Italy), Royal Society (UK)

Australian Academy of Sciences, Royal Flemish Academy of Belgium for Sciences and the Arts, Brazilian Academy of Sciences, Royal Society of Canada, Caribbean Academy of Sciences, Chinese Academy of Sciences, French Academy of Sciences, German Academy of Natural Scientists Leopoldina, Indian National Science Academy, Indonesian Academy of Sciences, Royal Irish Academy, Accademia Nazionale dei Lincei (Italy), Academy of Sciences Malaysia, Academy Council of the Royal Society of New Zealand, Royal Swedish Academy of Sciences, and Royal Society (UK)

If anyone can find examples of governmental scientific organizations that deny the consensus position, I'd be happy to make a second list of links. Saudi Arabia and Kuwait have long been hostile to international climate change negotiations, so their scientific organizations may well have official positions opposing the consensus. However, the Saudis are apparently changing their stance, as announced in May 2006 at a U.N. sponsored meeting in Germany. "I believe the petroleum industry should actively engage in policy debate on climate change as well as play an active role in developing and implementing carbon management technologies to meet future challenges," said the president of the Saudi state-run oil industry giant, Aramco. In 2005, both Saudi Arabia and Kuwait signed and ratified the Kyoto Protocol to limit greenhouse gases. The Protocol does not call on them to reduce their emissions.

In summary, there is an overwhelming level of scientific consensus on human-caused climate change. Those who defend the contrary view are fond of pointing out that we shouldn't stifle their opposing point of view, since heroes like Galileo with his sun-centered solar system view and Wegener with his continental drift theory both challenged the overwhelming scientific consensus of their day and were proved to be correct. That is true. However, Galileo and Wegener did not have the public relations staff of multi-billion dollar companies helping them promote their contrary views. I'm not too worried about the contrarian view of human-caused climate change being stifled, and contrarians are encouraged to publish in the peer-reviewed scientific literature. I would like to see the media sharply reduce their coverage of the contrary views of such think tanks as the Competitive Enterprise Institute, George C. Marshall Foundation, and scientists such as S. Fred Singer of SEPP. Getting one's climate science information from these sources it similar to getting one's news from a tabloid newspaper. Sure, some of the stories are true, but a lot of the material is of questionable quality, to say the least. The media should focus on getting their scientific information from leading scientists who regularly publish in the peer-reviewed scientific literature.

Jeff Masters

Climate Change

Updated: 9:00 PM GMT on August 16, 2011

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Al Gore's An Inconvenient Truth movie review

By: JeffMasters, 5:02 PM GMT on June 19, 2006

Al Gore's global warming movie, "An Inconvenient Truth," aims to call attention to the dangers society faces from climate change, and suggests urgent actions that need to be taken immediately. It is based on a slide show on climate Gore has presented to audiences worldwide over 1000 times in the past 15 years, but it is not purely a documentary. Gore's movie is an advocacy piece that is part documentary, part biography, and part campaign ad. I'll discuss all three of these aspects below. In brief, Al Gore has the right idea--climate change is an urgent issue that requires immediate action, and his thoughtful movie is a welcome addition to the usual array of mindless Hollywood summer fare. However, the movie has flaws. The presentation of the science is good, but not great--I rate it B minus. The excessive details on Al Gore's life make the movie too long, and his insistence on using the movie as something of a campaign ad detracts from its message.

An Inconvenient Truth as a biography of Al Gore
The creators of the movie presumably thought that simply presenting Gore's slide show would be too dull, so they decided to give the movie some human interest by interweaving a biography of Al Gore's life. Al Gore has led an interesting life, but "interesting" and "Al Gore" are not words one can often put together. As my daughter noted in her movie review yesterday, Al Gore is boring, and the 20 minutes or so of biography presented in An Inconvenient Truth is too much for a movie that is 1 hour and 36 minutes long. For example, I didn't really need to see the road where Al Gore totaled his car when he was 14 years old, or a replay of his loss in the 2000 election. On the other hand, some details of his past were interesting and relevant, such as the fact that he took college courses in the late 1960s from Harvard's Dr. Roger Revelle. Revelle and Dr. Charles Keeling were the pioneers in measurements of atmospheric CO2, and thus Gore got a very early exposure to the now infamous "Keeling Curve" (Figure 1), showing the build-up of atmospheric CO2. This early exposure to the significant impact humans were having on the atmosphere deeply affected Gore, and in the movie he details efforts he made to call attention to the issue long before most people had heard of it, back in the 1970s and 80s. Gore's slide show appropriately displays many graphs of the Keeling Curve, as it is probably the most important and most famous finding in climate change science.


Figure 1. The Keeling Curve is a record of CO2 measurements taken at he top of Mauna Loa volcano in Hawaii since 1958.

The science of An Inconvenient Truth
The science presented is mostly good, and at times compelling, but there are a few errors and one major distortion of the truth. Gore does an excellent job focusing on the most important issues, and usually presents them with a minimum of hype and distortion. The only exception to this comes in his treatment of global warming and extreme weather events such as hurricanes.

Basic global warming science
Gore begins the science part of his talk with a very easy to understand presentation on the basics of how the greenhouse effect works. His speech is clear, the graphics top notch, and he spices it up with a hilarious two-minute cartoon depicting roughneck global warming gases preventing poor Mr. Sunbeam from escaping Earth's atmosphere. Gore addresses the argument of skeptics who claim that the Earth is too big for humans to affect by showing Space Shuttle photos of how thin the atmosphere really is compared to the vast bulk of our planet. "The problem we now face is that this thin layer of atmosphere is being thickened by huge quantities of carbon dioxide," he asserts, which is not correct. The build-up of CO2 has virtually no effect on the density or thickness of Earth's atmosphere. The correct thing to say would have been, "The problem we now face is that this thin layer of atmosphere is being made more opaque to the transmission of infrared radiation (heat) by huge quantities of carbon dioxide."

Glaciers
Gore shows an impressive series of "then and now" images documenting the widespread retreat of many glaciers over the past century. Most dramatically, he shows Tanzania's Mt. Kilimanjaro, whose 11,000 year-old glaciers are almost gone. While not all the world's glaciers have retreated in the past century, Gore's presentation is an effective and reasonable way to show how global warming has affected the majority of the world's glaciers. Greenhouse skeptics, including Michael Crichton in his State of Fear book, are fond of bashing those who use Mt. Kilimanjaro as a poster child for demonstrating global warming. They cite scientific research showing that the glacial retreat on Mt. Kilimanjaro is due to drying of the atmosphere, not global warming. However, as discussed at great length in a realclimate.org post, the research which supposedly supports the skeptics' claims has been widely misquoted and misinterpreted, and much of Kilimanjaro's melting can indeed be ascribed to warming of the atmosphere since 1960.

Gore does an excellent job discussing the ice caps of Greenland and Antarctica. Again, Gore's graphics are superb, and he does a nice job narrating. He shows animations of what a 20-foot rise in sea level would do to Manhattan, Florida, India, and China. A 20-foot sea level rise is what we expect if all of Greenland or all of the West Antarctic Ice Sheet were to melt. Such a 20-foot rise is not expected by 2100, and it would have been appropriate for Gore to acknowledge that the consensus of climate scientists--as published in the most recent report by the United Nations' Intergovernmental Panel on Climate Change (IPCC)--is that sea level is likely to rise between 4 and 35 inches, with a central value of 19 inches, by 2100. He should have also mentioned that temperatures in Greenland in the 1930s were about as warm as today's temperatures, so the current melting of Greenland's glaciers does have historical precedent. Nevertheless, the risk of a catastrophic melting and break-up of the Greenland or West Antarctic ice sheets is very real, when we consider that sea level before the most recent ice age was 15 feet higher than it is now. Gore is right to draw attention to what might happen if sea level rose 20 feet.

Drought and heat waves
An excellent discussion of the most serious climate change issue our generation is likely to face, the threat of increased drought and reduced water supplies, is presented. Gore makes reference to the extreme heat wave that affected Europe during the summer of 2004, and I was glad to see that he didn't blame the heat wave on global warming--he merely said that more events of this nature will be likely in the future.

Hurricanes and severe weather
The biggest failure in the movie's presentation of science comes in the discussion hurricanes and severe weather events. The devastation wrought by Katrina is used to very dramatic effect to warn of the dangers climate change presents. We are told that Katrina grew "stronger and stronger and stronger" as it passed over the warm waters of the Gulf of Mexico that were heated up by global warming. We are told that global warming is increasing the intensity of hurricanes, but not provided information on the great amount of uncertainty and vigorous scientific debate on this issue. Graphs showing recent record insurance losses from natural disasters are presented, but no mention is made of how increasing population and insistence on building in vulnerable areas are the predominant factors causing recent high insurance claims from disasters such as Katrina. Gore points to some unprecedented events in 2004 as evidence of increasing severe weather events worldwide--the record 10 typhoons in Japan, the most tornadoes ever in the U.S., and the appearance of Brazil's first hurricane ever. However, examples of this kind are meaningless. No single weather event, or unconnected series of severe weather events such as Gore presents, are indicative of climate change. In particular, the IPCC has not found any evidence that climate change has increased tornado frequency, or is likely to. Gore doesn't mention the unusually quiet tornado season of 2005, when for the first time ever, no tornadoes were reported in Oklahoma in the month of May.

Other science
Gore presents many other important aspects of climate change, including the threat of abrupt climate change leading to a shut-off of the Gulf Stream current, the increase in damaging insect infestations and tropical diseases, loss of coral reefs, loss of ice in the polar ice cap, and melting of permafrost in the Arctic. With the possible exception of his treatment of the spread of tropical diseases, all of these issues were presented with sound science.

An Inconvenient Truth as a campaign ad
Gore has repeatedly said that he has no intention of running for president again, and that this movie was created as part of his life-long passion to protect the environment. Gore undoubtedly does care very deeply about the planet, but this movie very much looks like a campaign ad. We are shown many scenes of Gore being applauded, Gore traveling the globe to present his slide show, and Gore working to uncover evidence of Republican shenanigans to alter or suppress climate change science. Gore is portrayed as a humble and tireless crusader for good, and if the movie is not intended to promote his political ambitions, it is certainly intended to benefit the Democratic Party. All this gets in the way of the movie's central message.

Conclusion
At the end of the movie, we are presented with the same image that Gore started the movie with, that of a beautiful river in the wilderness. Throughout the movie, Gore emphasizes how beautiful and special our planet is, and he does an effective job conveying this. He also makes a powerful case that something can and should be done to protect the planet, and it is worth hearing his message, even if the science is flawed and the messenger does get in the way of the message. Overall, the movie rates 2.5 stars--worth seeing, but you might want to wait until the DVD comes out.

At the end of the movie, Gore presents some tips on how everyone can contribute, and points people to his web site, www.climatecrisis.net. However, I would recommend that people who want to get educated about climate change get their information from web sites not associated with a politician; perhaps the least politicized source of information is the latest scientific summary of the Intergovernmental Panel on Climate Change(IPCC), a group of over 2000 scientists from 100 countries working under a mandate from the United Nations in the largest peer-reviewed scientific collaboration in history.

Jeff Masters

Book and Movie Reviews

Updated: 12:02 AM GMT on August 16, 2011

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A quiet Father's Day

By: JeffMasters, 3:43 PM GMT on June 18, 2006

Since the Atlantic continues to show minimal tropical weather activity today, I asked my 10-year old daughter to write today's blog as a Father's Day present for me. So here, in her own words, is her review of Al Gore's global warming movie, "An Inconvenient Truth", which we saw this weekend:

"Al Gore is really boring, but he has the right idea."

I don't disagree with either point, and will post my own longer review on Monday. Have a great Father's Day, everyone!

Jeff Masters/Ellie Masters

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A quiet Saturday in the tropics

By: JeffMasters, 4:03 PM GMT on June 17, 2006

It's a quiet Saturday for the tropical Atlantic today. There is one tropical wave worth mentioning, a large area of thunderstorms approaching Puerto Rico and the northeastern Leeward Islands. The shower activity has increased in this disturbance over the past 24 hours, but westerly winds associated with the subtropical jet stream are creating 20 - 30 knots of wind shear. This shear is ripping away the tops of the thunderstorms and blowing them to the east, creating a large region of high cirrus clouds downwind. The disturbance is expected to move northwest over the next few days, and not develop, due the the presence of high wind shear. There is one model--the Canadian model--which does develop this wave into a tropical cyclone that threatens Bermuda next week. However, all of the other global models are showing that wind shear will increase, preventing any development. The recent runs of most of the computer models are showing quite a bit more wind shear than before over the entire Atlantic Ocean for the upcoming week, reducing the chances that we will see any tropical storms developing. The last week of June looks like a better bet for tropical storm formation.



Also notable on today's satellite image is the presence of plenty of African dust. June and July are the peak months for African dust over the Atlantic, and any tropical cyclone that tries to form will have to battle the dry air that accompanies all this dust.

Jeff Masters

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A quiet weekend for the tropics

By: JeffMasters, 6:45 PM GMT on June 16, 2006

The tropical Atlantic remains quiet today. I should mention a swirl of low clouds between Africa and the Antilles islands near 10N 35W that has a low-level circulation with a few thunderstorms, but I don't expect this low to develop. It is headed northwest towards an area of high wind shear and water temperatures below the 80 F threshold needed for tropical storm formation.

Thunderstorm activity in the ITCZ between Africa and the Lesser Antilles islands remains disorganized. The global forecast models do not show tropical storm development in the next three days, so it should be a quiet weekend. Several models are pointing to the possibility of tropical storm development around the middle of next week south of Bermuda, but the liklihood of this appears low at this time. The best chance of tropical storm development this month is probably during the last week of June, as the GFS model is still indicating favorable conditions for this time period.

Have a great weekend, everybody! I plan on catching Al Gore's movie on global warming this weekend, and will be writing a review that evaluates its scientific quality.

Jeff Masters

Updated: 7:10 PM GMT on June 16, 2006

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The tropics go quiet

By: JeffMasters, 4:20 PM GMT on June 15, 2006

Alberto has transitioned to a powerful extratropical storm over the Canadian Maritime provinces today, and no new threat areas have emerged over the Atlantic that look likely to become our next tropical storm--Beryl. Wind shear increased over the Caribbean last night, tearing apart two tropical waves that were producing some strong thunderstorms. The thunderstorm activity in the ITCZ off the coast of Africa remains disorganized. All of the global forecast models have backed off on forecasting tropical storm development in the next five days, although the GFS model is still predicting one or two tropical storms might form between Africa and the Lesser Antilles Islands the last week of June. It looks like we're in for a quiet period for at least the next three days. This is good news for the 300 boats sailing from Newport, RI to Bermuda on Friday as part of the Newport Bermuda Race. Alberto cleared out just in time!

Jeff Masters

Updated: 4:52 PM GMT on June 15, 2006

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Alberto analyzed; June tropical outlook

By: JeffMasters, 4:53 PM GMT on June 14, 2006

Alberto has been downgraded to a tropical depression, and continues heading northeast across the Carolinas towards the Atlantic Ocean. The storm is undergoing the transition from a tropical system to an extratropical storm, and is expected to intensify into a powerful non-tropical low pressure system with 50 mph winds on Thursday once it moves out over the open Atlantic. The main threat from Alberto today remains heavy rain and tornadoes, and several tornado warnings have already been issued today for coastal North Carolina. Six tornadoes touched down in South Carolina yesterday, causing minor damage and some injuries. Alberto pushed a storm surge of 4-5 feet in the Big Bend area of coastal Florida, but no significant damage from this flooding has been reported. Perhaps this large surge surge from a mere 50-mph tropical storm will make local planners leery of permitting a controversial 7,000-unit condominium complex to be built in Taylor County where Alberto came ashore. I'm all for sensible development, but building in coastal wetland subject to large storm surges is certainly not sensible--especially with hurricane activity in the Atlantic expected to be higher than usual for at least 10-20 more years.

Analyzing Alberto's life
Alberto formed from a tropical wave that moved off of the coast of Africa on May 30. The wave tracked farther north than usual for June, entering the eastern Caribbean on June 5, and the western Caribbean on June 8. The wave interacted with the unsettled weather of the Intertropical Convergence Zone (ITCZ), which has been able to push unusually far north for this time of year. The interaction between the ITCZ and the African wave produced Alberto on June 9. It is uncommon for a June tropical storm to form from an African wave; usually, the left-over remains of a cold front or trough of low pressure serve as the seed for June storms. However, last year's Tropical Storm Arlene also formed from an African tropical wave at about the same time of year. It's worth noting that both the GFS and Canadian models made very good forecasts of the genesis of Alberto. The best track forecasts were made by the GFS model, but the official NHC forecast outperformed all the models.


Figure 1. Track of Tropical Storm Alberto (with winds speeds in mph plotted every six hours) overlaid on a plot of Tropical Cyclone Heat Potential (TCHP) from June 12, 2006. The TCHP is a measure of the total heat content of the ocean, and high values of TCHP have been shown to aid hurricane intensification. In this image, the high heat-content waters of the Loop Current are visible as the lighter shades of green extending from the Yucatan Channel northward into the Gulf of Mexico. Note that Alberto spent much of its life over the Loop Current. Image credit: NOAA/AOML.

Alberto struggled over its entire life with wind shear of 20-30 knots overhead. Why, then, was it able to put on a surprising burst of intensification on Monday morning over the Gulf of Mexico? One possibility is that the a brief lull in the wind shear allowed Alberto to take advantage of the warm waters of the Loop Current. As seen in Figure 1, the Loop Current was pumping a long tongue of waters with high heat content into the central Gulf of Mexico. Alberto spent much of its life over this high heat content water. Just as Alberto moved away from the Loop Current, wind shear appeared to drop by about 10%, based on satellite estimates I viewed at the University of Wisconsin's CIMSS site. This small relaxation in shear may have been enough to allow Alberto to take advantage of the warm Loop Current waters and put on a burst of intensification. Shortly thereafter, the shear increased by 10%, Alberto left the Loop Current, and the intensification stopped.

Tropical outlook for the rest of June
Past history has shown that an active June in the Atlantic has no correlation with hurricane activity later in the season. However, the model forecasts over the past few days from the reliable GFS, NOGAPS, and Canadian models are showing a weather pattern more typical of mid-July developing over the tropical Atlantic. This may make for a exceptionally active June. The Intertropical Convergence Zone (ITCZ) is forecast to be far more active and further north than usual, and the GFS model has been predicting that one or two tropical cyclones may form in the mid-Atlantic from African waves interacting with the ITCZ. This is almost unheard of in June. Wind shear over the Caribbean and tropical Atlantic is expected to be much below normal, and with sea surface temperatures 0.5 - 1.5 degrees C above normal, it would not surprise me to see two more named storms this June. One saving grace is that the subtropical jet stream is expected to stay active and relatively far south, with should act to bring hostile wind shear to any storm that might move into the Gulf of Mexico. In addition, a series of strong troughs are forecast to move across the Atlantic Ocean the remainder of the month, which should act to recurve any storm that might form there away from land.

While there is nothing threatening looking out there today, we should keep an eye on the ITCZ just off the coast of Africa south of the Cape Verde Islands, and the region just north of Panama, in the coming days.

Jeff Masters

Updated: 5:01 PM GMT on June 14, 2006

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Alberto brings beneficial rains, modest damage

By: JeffMasters, 9:19 PM GMT on June 13, 2006

Alberto made landfall at 12:45pm Tuesday near Adams Beach, Florida, about 50 miles (80 kilometers) south of Tallahassee. Alberto had maximum sustained winds of 50 mph at landfall, and brought a storm surge of up to 5 feet near Cedar Key. No major flooding damage has been reported, however. Power outages to 21,000 people have occurred, and tree damage appears to be the predominant problem from the storm. No tornadoes have occurred today in Florida, but there have been several tornado reports from Georgia and South Carolina, including a report of a tornado on the ground at Beaufort Marine Base in South Carolina.

Alberto will weaken to a tropical depression as it crosses Georgia tonight. The storm will likely be declared extratropical on Wednesday, when it emerges into the Atlantic Ocean. The remains of Alberto should then reintensify some as a non-tropical low pressure system over the open Atlantic Ocean, where it will only be of concern to shipping.


Figure 1. Total rain from Alberto estimated by Doppler radar.

It appears now that Alberto may save millions of dollars in agricultural losses and firefighting expenses due to the heavy rains it has brought to drought-parched Florida. Several of the over 100 fires burning in Florida have already been extinguished by Alberto's rains.

Tomorrow, I'll analyze Alberto's sudden burst of intensification Monday morning, and report on what the rest of June may hold for us. It could be an exceptionally active June.

Jeff Masters

Updated: 9:22 PM GMT on June 13, 2006

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Alberto storms ashore

By: JeffMasters, 1:35 PM GMT on June 13, 2006

Alberto is coming ashore in the sparsely populated Big Bend region of the Florida coast this morning. After a surprising burst of intensification that brought Alberto to the verge of hurricane status yesterday, dry air, cooler waters, and the continued 20-30 knots of wind shear have kept Alberto from reaching hurricane strength. Alberto is making landfall as a tropical storm with top winds between 45 mph and 50 mph. At 8 am EDT at Cedar Key the sustained winds were south at 33 mph gusting to 43 mph. At the Apalachicola buoy, about 45 miles south of the center of Alberto, winds were west at 36 mph gusting to 45 mph. The C tower in Apalachee Bay, just west of the storm center, winds were out of the northwest at 49 mph with gusts to 59 mph--but the wind instrument is 100 feet above the surface where wind speeds can be quite a bit higher than the surface. The 8am Hurricane Hunter flight found top winds of only 65 mph at 5000 foot altitude. A strong burst of deep convection has formed over the northern portion of the storm in the past few hours, but this is too late to bring Alberto up to hurricane strength.


Figure 1. Latest storm-centered satellite image of Alberto.

The biggest threat from Alberto remains storm surge. At 8 am EDT the tide at Cedar Key was about 3 to 4 feet above normal, and areas between Cedar Key and near where the center makes landfall to the north can expect storm surge heights of up to seven feet. Since this is a relatively unpopulated stretch of coast, damage should be relatively low. Another concern is tornadoes, but none have been reported yet in northern Florida today. At least two tornadoes were reported yesterday, one of which did minor damage at Jacksonville Beach.

Alberto will bring heavy rain and the threat of tornadoes to southern Georgia, South Carolina, and North Carolina over the next 36 hours, but the storm is not expected to re-intensify once it reaches the open Atlantic. At best, Alberto will bring top winds of 45 mph to these states.

I'll be back with an update later this afternoon.

Jeff Masters

Updated: 2:51 PM GMT on June 13, 2006

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Alberto Update

By: JeffMasters, 4:08 AM GMT on June 13, 2006

This is Shaun with the latest update.

The current regional radar loop (Figure 1) shows extensive heavy precipitation already pouring into Florida from Alberto. The heaviest activity is right where the panhandle meets the mainland part of the state.

The latest recon mission reported a 68 kt wind at 700 mb, which translates to near 60 kt winds with the 90% reduction to the surface. This means that Alberto is still a tropical storm at the moment. I say at the moment because although water temperatures remain near 79-80 degrees, the atmosphere ahead of the storm center is expected to become more unstable, resulting in some intensification of the storm, possibly to hurricane strength before landfall.

Indeed, the official NHC track (Figure 2) shows a strengthening of the storm just before landfall. The main problem for the Florida coast will be the 8-10 foot storm surge that is expected. This height is especially high for a tropical storm so residents should be aware.

A look at the severe map (Figure 3) shows most of Florida and the coasts of Georgia and South Carolina are under some sort of tropical storm of hurricane watch in anticipation of landfall midday Tuesday.

This sounds like the beginning of a long hurricane season.

Figure 1. Regional radar loop.

Figure 2. Official NHC track for Alberto.

Figure 3. Severe weather map.

Updated: 5:54 AM GMT on June 13, 2006

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Alberto nears hurricane strength

By: JeffMasters, 3:16 PM GMT on June 12, 2006

The latest report from the hurricane hunters found winds of 74 knots (85 mph) at flight level of 1500 feet, and a central pressure of 997 mb, down 4 mb from the 8am EDT penetration. After surviving some very strong wind shear last night, Alberto has reorganized, and a new center has formed under the deep convection on the east side of the storm. The old center is still visible on satellite imagery, drifting southward over the Gulf of Mexico. Spiral banding has appeared on both visible satellite imagery and the Tampa radar animation.


Figure 1. Accumulated rain so far from Alberto, as estimated by the Tampa radar.

All this strengthening occurred in the face of strong wind shear of 20-30 knots, which is unusual. I was calling for a 10% chance of Alberto becoming a hurricane, but Alberto certainly has other ideas! The storm's central pressure was a very unimpressive 1006 mb last night when I thought the storm might get ripped apart, but the 9 mb drop in pressure since then is an impressive achievement for a storm under 20-30 knots of wind shear. The shear has not changed much in the past 12 hours, nor is it expected to do so over the next few days. This should limit Alberto's intensification. Hurricane Ophelia last year strengthened in the face of similar amounts of shear, and I anticipate that Alberto will grow no stronger than Ophelia. Maximum sustatined winds of 80 mph are probably the highest we will see from Alberto.

The major threat of damage with Alberto now appears to be storm surge, with a surge of 8 - 10 feet possible over portions of the west coast of Florida. The waters off the coast are very shallow for a long stretch, which allows a rather large surge to build up. High winds will be a problem for mobile homes, and cause moderate tree damage and power outages in the affected area. Heavy rain will also be a concern, but as I discussed yesterday, this may be more of a boon than a bane given Florida's moderate drought conditions. Rain amounts of up to six inches have fallen in portions of the Keys and Naples, Florida.

We'll update this blog later today as conditions warrant.

Jeff Masters

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Alberto nears hurricane strength

By: JeffMasters, 3:16 PM GMT on June 12, 2006

The latest report from the hurricane hunters found winds of 74 knots (85 mph) at flight level of 1500 feet, and a central pressure of 997 mb, down 4 mb from the 8am EDT penetration. After surviving some very strong wind shear last night, Alberto has reorganized, and a new center has formed under the deep convection on the east side of the storm. The old center is still visible on satellite imagery, drifting southward over the Gulf of Mexico. Spiral banding has appeared on both visible satellite imagery and the Tampa radar animation.


Figure 1. Accumulated rain so far from Alberto, as estimated by the Tampa radar.

All this strengthening occurred in the face of strong wind shear of 20-30 knots, which is unusual. I was calling for a 10% chance of Alberto becoming a hurricane, but Alberto certainly has other ideas! The storm's central pressure was a very unimpressive 1006 mb last night when I thought the storm might get ripped apart, but the 9 mb drop in pressure since then is an impressive achievement for a storm under 20-30 knots of wind shear. The shear has not changed much in the past 12 hours, nor is it expected to do so over the next few days. This should limit Alberto's intensification. Hurricane Ophelia last year strengthened in the face of similar amounts of shear, and I anticipate that Alberto will grow no stronger than Ophelia. Maximum sustatined winds of 80 mph are probably the highest we will see from Alberto.

The major threat of damage with Alberto now appears to be storm surge, with a surge of 8 - 10 feet possible over portions of the west coast of Florida. The waters off the coast are very shallow for a long stretch, which allows a rather large surge to build up. High winds will be a problem for mobile homes, and cause moderate tree damage and power outages in the affected area. Heavy rain will also be a concern, but as I discussed yesterday, this may be more of a boon than a bane given Florida's moderate drought conditions. Rain amounts of up to six inches have fallen in portions of the Keys and Naples, Florida.

We'll update this blog later today as conditions warrant.

Jeff Masters

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Alberto makes a comeback

By: JeffMasters, 12:45 PM GMT on June 12, 2006

Alberto survived some very strong wind shear last night, and is in much better shape this morning. Deep convection for all of Alberto's life had been confined to the storm's east side, but has now built westward and almost reaches the center. Spiral banding has appeared on both visible satellite imagery and the Tampa radar animation. The storm's central pressure was a very unimpressive 1006 mb last night when I thought the storm might get ripped apart, but has dropped to 1001 mb this morning, according to the latest 8am EDT Hurricane Hunters report. Peak winds are probably around 50 mph--buoy 42003 in the Gulf of Mexico measured peak winds of 43 mph earlier this morning as Alberto passed overhead.


Figure 1. Accumulated rain so far from Alberto, as estimated by the Tampa radar.

All this strengthening occurred in the face of strong wind shear of 20-30 knots. The shear has not changed much in the past 12 hours, nor is it expected to do so over the next few days. This should limit Alberto's intensification, keeping the storm below hurricane strength. In fact, the latest visible satellite imagery shows the shear once more blowing the deep convection away from the center, exposing the center once more. I expect Alberto will undergo some fluctuations in strength over the next day as the storm battles the shear. The most likely peak winds at landfall are in the 45 - 60 mph range. Alberto has about a 10% chance of reaching hurricane strength before landfall.

The major threat of damage with Alberto now appears to be storm surge, with a surge of 4 - 8 feet possible over portions of the west coast of Florida. The waters off the coast are very shallow for a long stretch, which allows a rather large surge to build up. Heavy rain will also be a concern, but as I discussed yesterday, this may be more of a boon than a bane given Florida's moderate drought conditions. Rain amounts of up to six inches have fallen in portions of the Keys and Naples, Florida.

We'll update this blog later today as conditions warrant.

Jeff Masters

Updated: 12:49 PM GMT on June 12, 2006

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Little Change to Alberto

By: JeffMasters, 4:38 AM GMT on June 12, 2006

This is Shaun reporting for Dr. Masters one last time before he updates us all tomorrow.
Little has changed in the structure of Alberto since the last recon flight investigated the storm. The reported center of the storm is actually the mean position of several swirls within the interior of the storm.
The satellite image (Figure 1) shows that most of the deep convection remains on the east side of the storm west Florida will soon be receiving heavy rain and thunderstorms as seen on the regional radar (Figure 2).
As for the movement of the storm, it was moving north-northeastward at 6 mph as per the latest update. The upper-level ridge of high pressure over Florida has weakened, but the lower-level ridge has remained strong while shifting to the north. This, combined with southwesterly upper-level flow pattern, will create a strong shear environment that should do a good job of ripping Alberto apart.
After its turn to the northeast, some strengthening of the system is possible due to weakening shear, but any strengthening will not be too intense.
The official forecast track has not changed (Figure 3) very much since the last update.
Figure 1. IR satellite image of Alberto.

Figure 2. Regional radar for Florida.

Figure 3. Official NHC forecast track.

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Alberto is here!

By: JeffMasters, 3:20 PM GMT on June 11, 2006

Well, I'm back to blogging on the hurricane season of 2006 earlier than I had hoped. We managed to put together a string of nine straight days without an active tropical cyclone in the Atlantic this hurricane season, but now that streak has come to an end with the formation of Tropical Storm Alberto. I scheduled my summer vacation for the period I though most likely to have ten straight days without tropical activity, but the tropics had other ideas.

Alberto is a fairly typical-looking June tropical storm. The satellite presentation is not very impressive this morning, with most of the deep convection lying to the east of the exposed center. Strong westerly winds associated with the subtropical jet stream are removing the deep convection from the center. This wind shear is creating a very hostile environment for Alberto to survive in, let alone strengthen. With the shear forecast to strengthen, I would not be surprised to see Alberto ripped apart tonight. If this scenario does occur, the low level swirl of clouds associated with Alberto's core will drift into the center of the Gulf of Mexico and gradually decay. The main moisture to the east of the center will separate and get pulled across Florida. If Alberto manages to survive, a strong trough of low pressure moving over the Eastern U.S. will recurve the storm over Central and Northern Florida, where Alberto will rapidly lose tropical characteristics and become a very rainy low pressure system. Alberto currently has tropical storm force winds of 40-45 mph in a very small area to the northeast of the center. The central pressure has actually risen 2 mb to 1004 mb since 7 am EDT this morning, proving that this is not a healthy tropical storm. I give Alberto a less than 5% chance of making hurricane status. It is far more likely (40% chance) that Alberto will get torn apart by high wind shear before making landfall on Florida's west coast. The most likely scenario is that Alberto will hit the west coast of Florida as a weak tropical storm with maximum winds of 40 - 50 mph.


Figure 1. Estimated precipitation for Alberto from the Key West radar.

Residents of the west Florida coast should have little problem with wind damage or storm surge from this storm. The greatest threat from Alberto will come from its rains. Already today, the outer bands of Alberto have dumped over six inches of rain on portions of the Florida Keys (see Figure 1), and over 12 inches on portions of Western Cuba. These rains will likely cause localized flooding problems, but given that most of Florida is under moderate drought, Alberto may end up being more of a blessing than a bane for the state.


Figure 2. Current drought map shows moderate drought over most of Florida. The area Katrina hit is looking very dry as well, but let's hope they break this drought from something other than a hurricane!

If there is a significant change to Alberto today, Shaun will update this blog tonight (or I will, if I find another hotel with good wireless Internet, as I continue my drive home from vacation). Otherwise, expect an update on Monday.

Jeff Masters

Updated: 3:21 PM GMT on June 11, 2006

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First Tropical Depression has formed!!!

By: JeffMasters, 4:37 PM GMT on June 10, 2006

Since Dr. Masters is on vacation for the next few days, the other meteorologists here at Weather Underground will fill in for him as best as we can. For even more information on TD One, please see WCSC Hurricane Center's blog.

TD One has indeed formed and Figure 1 shows a ball of dense clouds spreading over western Cuba and a smaller ball of clouds just off the coast of Belize. Maximum sustained winds are near 35 mph with higher gusts and the storm has a poorly defined center.

The official NHC track (Figure 2) shows a general northeastward curve of TD One through the Gulf of Mexico, becoming Tropical Storm Alberto and then crossing the heart of Florida as a tropical storm.

Historically speaking (Figure 3), storms that have passed near where TD One currently lies generally move through the Gulf of Mexico while recurving towards Florida. There have been a few storms, however, that pinpointed western Florida and the Mississippi/Alabama area.

Let's wait a bit for the hurricane hunter aircraft to investigate the depression later in the day. But, of immediate importance is the torrential rainfall that is possible for the Cayman Islands and western Cuba. Monstrous flash flooding and mudslides are certainly possible so residents should be aware.

Figure 1. Satellite image of TD One.

Figure 2. NHC track.

Figure 3. Historical tracks.

Updated: 4:38 PM GMT on June 10, 2006

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Interview with the NW Florida Daily News - Part 4

By: JeffMasters, 4:42 PM GMT on June 09, 2006

This is part 4 of an interview I did with the Northwest Florida Daily News of Fort Walton Beach, Florida, that was published on Sunday, May 28. The questions were posed to me by Del Stone Jr., Deputy Managing Editor and self-admitted weather nut. I'll be back to live blogging on June 14.

Q. Our nation's first line of defense against hurricanes is the National Hurricane Center. Is NHC adequately funded for such a role?

A. Things have improved considerably, thanks to some increased funding autorized by Congress in the wake of the hurricanes of 2004 and 2005. The Hurricane Center has been understaffed for a number of years, especially since they were tasked with the additional job of writing all the advisories for Eastern Pacific hurricanes. However, NHC just added four new hurricane forecasters last month, thanks to the a special requisition championed by Sen. Bill Nelson (D-Fla). NHC now has ten hurricane forecasters, and this will help greatly. NOAA also got money for a new weather research airplane, which will help out our hurricane reconnaissance needs. An additional $1.4 million has been proposed this year to improved buoys in the Atlantic. The only area where not much money was made available was for hurricane research. We need more dollars to fund development of better hurricane intensity forecasts. NOAA's Hurricane Research Division does fantastic work on this, and could probably significantly improve our hurricane intensity forecasts if they were able to add a few new scientists to research this.

Q. When a hurricane strikes, much of the damage is concentrated along the coastline. Obviously this raises questions about the wisdom of building in vulnerable areas, and materials used in such construction. If you could provide guidance to local governments and contractors about those two issues, what would it be?

A. The level of hurricane activity we experienced in the 1970s and 1980s--when most of the recent coastal development happened--was very low. The high levels of activity we've experienced since 1995 are what we can continue to expect for at least the next 10 or 20 years. Planners better get used to the idea of building for more frequent major hurricanes.

Q. Since 1995, hurricane activity "seems" to have increased. I qualify "seems" because the increase strikes me as more subtle than what might be apparent to somebody who is not a student of tropical meteorology. The 2004 and 2005 seasons were noticeably more active, even to a layman. Is this a result of a natural occurrence, the Atlantic decadal cycle, or is it a portent of things to come?

A. There are a lot of conflicting ideas on this among hurricane scientists. The majority view is that most of the increase since 1995 is due to a natural decades-long cycle called the Atlantic Multidecadal Oscillation (AMO), which is tied to sea surface temperatures and salinity in the Atlantic (the so-called "thermohaline circulation"). The trouble is, there is little observational support for this theory, as there are very few oceanographic measurements going back in time. In fact, ocean measurements taken in the past few years show a 30% slow down of the thermohaline circulation in the North Atlantic, which is the opposite effect one would expect to see if the AMO were truly causing the current upswing in hurricane activity. These measurements had a high potential for error, so more measurements are needed verify this finding. Dr. Kerry Emanuel, who developed much of the theory regarding hurricane intensification, has a new theory on the AMO--he thinks that this observed decades-long observed change in Atlantic hurricane activity is not a natural cycle. The lower levels of hurricane activity and lower SSTs observed from 1970-1995 were due to increased air pollution over the Atlantic reducing the sunlight. Since 1995, pollution control efforts, plus a significant increase in global warming, have acted to warm the oceans and drive increased hurricane activity. Except for the occasional strong El Nino year, he sees no end to the current pattern of increased hurricane activity in the Atlantic. I believe it is too early to say who's right. Dr. Emanuel hasn't published his findings yet; Nature magazine rejected his paper as being "too esoteric" for its readers.

Q. Lately a debate has sprung up among meteorologists about global warming and its relationship to hurricane formation. In your blog you have made a point of stressing the jury is still out on such a relationship, if I'm reading your blog correctly. The evidence so far seems inconclusive one way or the other. Do you have a personal opinion about such a relationship?

A. There's no doubt that there is an effect. Hurricanes are heat engines, and heating up the oceans makes stronger hurricanes. However, the amount of heating of the oceans we can blame on global warming, about 1 degree Fahrenheit, should (according to Dr. Emanuel's theory) cause at most a 2-3 mph increase in the winds of a storm like Katrina. Is the theory wrong? That's a question that is being seriously considered, and it is possible that global warming has made the strongest hurricanes much stronger than the theory would suggest. My opinion is that it its too early to tell. The database of global hurricane intensities is deeply flawed and doesn't extend over a long enough period of time to determine if there has been a significant increase in Category 4 and 5 hurricanes due to global warming.

Jeff Masters

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Interview with the NW Florida Daily News - Part 3

By: JeffMasters, 4:48 PM GMT on June 07, 2006

This is part 3 of an interview I did with the Northwest Florida Daily News of Fort Walton Beach, Florida, that was published on Sunday, May 28. The questions were posed to me by Del Stone Jr., Deputy Managing Editor and self-admitted weather nut. I'll be back to live blogging on June 14.

Q. Dr. William Gray is often quoted in the media for his pre-season storm predictions. Do you have any opinion one way or the other about the accuracy or efficacy of his reports?

A. I like his forecasts, as well as the seasonal hurricane forecasts put out by NOAA. They have some skill, and are valuable for helping determine if a hurricane season will be active or quiet.

Q. In the wake of last year's Hurricane Katrina, you were pointed in your remarks about the Bush administration's response to the storm. Taking into consideration all of the information about that response that has been released since then, has your opinion changed?

A. My criticism of the Bush Administration was primarily aimed at false comments made about the flooding of New Orleans being an unexpected disaster. This was a valid criticism, because this disaster has been expected by virtually everyone who studies hurricanes. I wasn't critical of the bungled response to the disaster, but certainly could have been. I also made a more general criticism of our political system, asking how it is that a nation as wealthy as ours was not able to evacuate the thousands of poor people who had no transportation of their own. I blamed this on the political process in our country where the wealth of one's campaign contributors is our politicians' primary concern, not the welfare of the poor in New Orleans. How is that Mexico, a much poorer country than our own, suffered only four deaths from Hurricane Wilma last year? Recall that Wilma hit the most heavily populated tourist area of Mexico as a Category 4 hurricane, and sat over Cancun for three days. And Hurricane Emily hit Mexico twice, first as a Category 4 at Cozumel, then as a Category 3 near Texas. But no one died in Emily! The difference is that the government of Mexico made a determined effort to evacuate those at risk, and provided transportation. In the U.S., a totally inadequate effort was made--in part, because the people affected were poor and of little concern to the politicians. The City of New Orleans was primarily responsible for coming up with a hurricane evacuation plan, with help from both the state and federal governments. All three branches of govenment failed this responsibility. In fact, a repeat of Katrina is entirely possible--newly re-elected Mayor Nagin has not yet come up with a workable plan to get those without transportation out of New Orleans for the next hurricane. How is it he got re-elected? According to a May 22 article on cnn.com, the bus drivers Nagin wants to use have not yet signed on, and the city has too few buses. The state and federal government are supposed to help out, but this hasn't happened yet. There are plans to get help from Amtrak and the commercial airlines, but again, there is nothing official. Is it asking too much for the federal government to step in and provide National Guard troops to transport people out? Mexico was able to get its citizens out of harm's way, why can't we? We need to take a hard look at our system of goverment in this country and answer that question. I think we need to move towards more public financing of elections and other reform measures such as Instant Runoff Voting to help reduce the influence of money on politics.

Q. It was recently suggested FEMA should be dismantled, to be replaced by a new and larger government disaster-response agency. Do you think such an agency would do a better job of assisting the victims of hurricanes, and if not, what would you advise lawmakers on Capitol Hill?

A. FEMA has not done well as a branch of the Department of Homeland Security (DHS), since that agency has given priority to anti-terrorism programs. FEMA and DHS are bureaucratically incompatible. For example, FEMA was using hurricane forecasts from NHC in the days leading up to Katrina, while DHS was using forecasts provided by Accuweather! The two sets of forecasts were considerably different, so the two agencies were never on the same page, even before the disaster. It makes sense to try putting FEMA back on its own again. However, this will not magically solve the agency's problems--remember that FEMA was an independent agency during the response to Hurricane Andrew in 1992, when the emergency manager of Dade County, Florida famously pleaded, "Where the hell is the cavalry?"

What is needed is for the Bush Administration to put competent people in charge of FEMA with disaster response experience. Political appointees like Michael Brown, who was an official with the International Arabian Horse Association before he came to FEMA, are a recipe for disaster. Congress needs to establish some sort of oversight on the administration of FEMA to ensure the organization is not a dumping ground for political appointees. Since President Carter formed FEMA, only Clinton appointed a FEMA director who had professional disaster management experience. And where was the press on this matter? Where was the investigative journalism needed to call attention to Michael Brown's lack of credentials before Katrina? I think in general the press has been far too negligent investigating and reporting on the qualifications of the government officials who are responsible for ensuring the safety of Americans. Another example of this is the agency responsible for food safety in America--the Department of Agriculture. Right now you'd have a hard time finding a federal agency more completely dominated by the industry it was created to regulate. But you don't hear the press saying much about this conflict of interest, despite the fact that each year food-borne illnesses kill four times as many Americans as died in Hurricane Katrina.

Jeff Masters

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Interview with the NW Florida Daily News - Part 2

By: JeffMasters, 5:12 PM GMT on June 05, 2006

This is part 2 of an interview I did with the Nothwest Florida Daily News of Fort Walton Beach, Florida, that was published on Sunday, May 28. The questions were posed to me by Del Stone Jr., Deputy Managing Editor and self-admitted weather nut. I'll be back to live blogging on June 14.

Q. Your bio indicates you faced a life-threatening situation while flying into Hurricane Hugo. Would you care to elaborate?

A. We were the first plane to intercept Hugo out near Barbados, and we elected to fly in at 1500 feet, expecting it to be a Category 3 storm (based on satellite estimates). Hugo turned out to be a Category 5, and nearly killed us. We hit 190 mph winds and 5.6 g's of acceleration in the eyewall (the wings are supposed to tear off at 6 g's), and had an engine catch on fire. The pilot lost control of the airplane, and we plummeted to 800 feet above the water before the pilot was able to regain control and extinguish the engine fire as we popped into the eye. Of course, our troubles weren't over then. We were in the eye of a Category 5 hurricane, had only three engines working, and needed to get through the eyewall again to escape. It's quite a story, and I have a long account posted on the tropical page of our web site, complete with photos I took in the eye.

Q. The evacuation for Hurricane Opal in 1995 was a debacle, with thousands of people stranded on highways as the hurricane struck. Afterwards, the National Hurricane Center seemed to revise its standards for evacuation, urging people to run from the water, hide from the wind. Assuming you agree with that assessment, how would you advise people in hurricane-prone areas to handle the question of evacuation?

A. If you have the flexibility, it is good to leave on your own a day before a likely evacuation order is issued. If I lived in the Keys, I would be out of there at the first hint of something serious that might move through. It takes a full 72 hours to evacuate Keys, I would be out of there at the first hint of something serious that might move through. It takes a full 72 hours to evacuate the Keys, and hurricanes like Rita and Wilma that intensify from tropical storm strength to Category 5 in about a day don't give us enough time to evacuate this highly vulnerable region.

In general, if you are still at home when the evacuation order is given, and live in a low-lying area at high risk of a storm surge, get out. Even if the highways are clogged, your chances of survival are still better than being on the coast. But as we saw during the evacuation of Houston during Hurricane Rita, and in Florida during Opal of 1995, evacuating from the wind doesn't always make sense. In fact, some estimates put the death toll from the evacuation due to Hurricane Rita at over 150 people, 23 of them when a bus carrying 45 nursing home evacuees erupted into flames and exploded on Interstate 45. Not counting Katrina, that's a higher death toll than any hurricane since Camille of 1969 (256 deaths). So, I think we need to think hard about evacuating the very sick and elderly from the wind. But, I've heard from a lot of people who've had bad experiences trying to ride out a hurricane in an evacuation zone. The mantra I've heard so many times, is, "I'll never ignore another evacuation order!" Your best bet is to always heed the evacuation order.

Q. Many people have become critical of media coverage of hurricanes. Television clips of correspondents standing in high winds as debris flies about have become commonplace. Do you feel this approach sensationalizes storm coverage? Do you believe it sets a bad example for viewers, encouraging them to do the same? What about be concentrated coverage from weather-exclusive entities like The Weather Channel? Does such coverage skew context, giving viewers an unrealistic picture of a storm's threat?

A. I don't believe a significant number of viewers will seek to go out in a hurricane in imitation of what they see TV reporters doing. However, hurricanes coverage is too sensationalized and over-hyped for my liking. Hurricane have become entertainment. One of these days, a reporter is going to get seriously injured by flying debris. I've championed on my blog the idea of having reporters doing their show from a safe place out of the wind, and sending wind-up toys out into wind to be blown away for dramatic effect. TV stations can make a creative and dramatic demonstration of the wind's power without endangering the lives of reporters.

Hurricanes are sensational enough in their own right, and do not need dramatization. My philosophy is to simply report from my own deep knowledge and understanding of these great storms, and not try to generate more hype in an effort to drive up ratings. In contrast, Accuweather's recent press release that the Northeast U.S. might be the target of a major hurricane this season was an excessively sensational."The Northeast is staring down the barrel of a gun," the article said. Language like this is effective in scaring people and driving up ratings, but is not an effective way of warning people in the Northeast of the true risks they face this year. Everyone living on the Atlantic Ocean is at risk, every year.

To be continued...

Jeff Masters

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Interview with the NW Florida Daily News

By: JeffMasters, 2:49 AM GMT on June 04, 2006

For the next week, I'll be posting excerpts from an interview I did with the Northwest Florida Daily News of Fort Walton Beach, Florida, that was published on Sunday, May 28. The questions were posed to me by Del Stone Jr., Deputy Managing Editor and self-admitted weather nut. I'll be back to live blogging on June 14.

Q. Is The Weather Underground your full-time job?

A. The Weather Underground is my full-time job, but I do a few guest lectures for the University of Michigan introductory meteorology classes.

Q. The $64,000 question, at least for people along the Emerald Coast here in Northwest Florida, is: What can we expect of the hurricane season in 2006? Specifically, do you have any feel for the number of named storms in 2006? I assume some of these storms reach the intensity of 2005's notorious Katrina, Rita and Wilma. Do you have a feel for how many?

A. The active hurricane period that began in 1995 should continue this year, since there is no strong El Nino event present, sea surface temperatures (SSTs) are .5 - 1.5 degrees C above normal across the tropical Atlantic, and the other four indicators we look at to predict seasonal hurricane activity are all positive. However, SSTs are nearly 1 degree cooler than last year's record levels, so I am not expecting another 2005. That was a once-in-a-lifetime year. My worst-case scenario calls for another year like 2004, with 15 to 20 named storms, and two to four major hurricanes hitting the U.S. My best-case scenario is still for an active year with 15 or so named storms, but with most of the storms recurving harmlessly out to sea. This happened in 1995, when the Bermuda High set up shop further east than usual, allowing the storms to recurve before hitting the coast. There will probably be at least three Category 4 or 5 hurricanes this year, and I expect one of these will make it into the top ten list for most intense Atlantic hurricanes on record. I don't look for anything like 2005, when three of the six most intense hurricanes on record occurred.

Q. At least one weather forecasting service has suggested the East Coast of the United States will face the brunt of this year's hurricane season. Do you agree or disagree with that prediction? If not, which part of the United States, in your estimation, should keep a closer eye on the tropics?

A. The jet stream pattern controls where hurricanes recurve. Our ability to forecast the jet stream pattern is limited; the best we can do is about a one week forecast. At times, we can get a general idea out to two weeks. Thus, it is difficult to make a skilled forecast at this time about which parts of the U.S. are likely to face the brunt of this year's hurricane season. Dr. Gray and some other researchers have shown that one can use statistical methods to make a slightly skillful prediction several months in advance about what parts of the U.S. might get hit most. Dr. Gray is predicting that the U.S. East Coast is more likely to get hit by a major hurricane then the Gulf Coast this year, but forecasts of this nature are only a little better than chance. Note that between 1000 and 3400 years ago, sediment records along the Gulf Coast show that Category 4/5 hurricane landfalls were about three to five times more common that we've seen during the past 1000 years. It's possible, but unlikely, that the intense hurricanes we've seen in the Gulf the past few years mark a return to this hyperactive pattern. It is not yet known if the Eastern U.S. coast also experienced this same hyperactive pattern 1000 to 3400 years ago; the researchers haven't done a full study of the sediment records there yet. I speculate that the East Coast saw a drop in intense hurricane during the same 1000 to 3400 year period, since a shift in the Bermuda High position steered most of the hurricanes into the Gulf of Mexico, and relatively few into the East Coast.

Q. I was asked to ask you: Is the Bermuda High, the system that sometimes steers hurricanes toward Northwest Florida, in a position to do the same again this year?

A. The position of the Bermuda High is controlled by the jet stream, and we won't know until about 1-2 weeks in advance what the Bermuda High might do.

To be continued...

Jeff Masters

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Hurricane season is here!

By: JeffMasters, 2:18 PM GMT on June 01, 2006

The hurricane season of 2006 is here! The date June 1 has taken on a notoriety second only to 9/11 in the consciousness of many of us, and the arrival of summer now has an ominous flavor--thanks to the unbelievable Hurricane Season of 2005. As I sat at my desk back on New Year's Day this year writing a blog on Zeta, the 28th named storm of that season, I wondered if the Hurricane Season of 2005 would ever end. Would an endless series of tropical storms develop through the winter, making the traditional June 1 start of hurricane season seem meaningless? Well, I am happy to report that the atmosphere sometimes does behave in a logical and predictable way. We've had a normal five straight months of no tropical storm activity in the Atlantic, leading up to today's official start to the season. And if you're not ready for hurricane season yet, then the Atlantic Hurricane Gods have benevolently granted you an extension to your preparation period--this year's season will have a slow start.


Figure 1.Graph of hurricane frequency for the Atlantic Ocean hurricane season. Image credit: NOAA.

What is typical for June?
June is normally the least active month of hurricane season (Figure 1). There have been 32 named storms in June since reliable records began in the Atlantic in 1944--an average of one every two years. There have been 10 June hurricanes (one every six years), and only two June major hurricanes. One of these major hurricanes was the notorious Hurricane Audrey, a Category 4 monster that killed 550 when it slammed into the Texas/Louisiana border on June 27, 1957. The only other June major hurricane was Hurricane Alma, which struck Cuba on June 8, 1966. Alma moved just offshore Florida's west coast as a Category 3 hurricane before weakening to a Category 2 hurricane and striking the Big Bend region of Florida's Panhandle. Alma killed 90.

Last year, June was four times more active than normal. Two June storms formed--Tropical Storm Arlene, which formed on June 8 and hit Alabama on June 11 as a 70 mph tropical storm, and Tropical Storm Bret, which formed June 28 and hit Mexico the next day as a minimal 40 mph tropical storm. The record for most named storms in June occurred in 1936 and 1968, when three storms formed.

What areas are at risk in June?
As we can see from examining the plots for 1936 and 1968, the Gulf of Mexico and the western Caribbean are the primary regions of formation for June tropical storms. The Gulf Coast, Cuba, and Mexico's Yucatan are the primary targets for these systems. June systems typically form from the remains of a cold front or trough of low pressure that moves out over the Gulf of Mexico or western Caribbean. These systems typically are slow to form, and require two to four days of "festering" before they acquire enough thunderstorm activity and spin to make it to depression stage. The tropical waves coming off of Africa this time of year are too far south to make it into the Caribbean sea, so we shouldn't expect any tropical storms to form in the central or eastern Caribbean.

What about SSTs?
Sea surface temperatures (SSTs) last year at this time were about 2 - 3.5 degrees C above normal, and were the highest ever measured in late May. This year, SSTs are about 1 - 1.5 degrees cooler, but are still above the 80 F threshold needed to get a tropical storm going. All we need is an initial disturbance to start with, and plenty of low wind shear to allow the convection to grow around it. SSTs will not be a limiting factor this June for hurricane development.


Figure 2. The GFS model forecast for June 11, 2006, shows a strong subtropical jet stream continuing to blow over the Gulf of Mexico. The strong winds of this jet will likely create too much shear for any tropical storms to form in the Gulf.

What about wind shear?
High wind shear is going to be a severe impediment to tropical storm formation for at least the first two weeks of June. The jet stream has split into two branches--the polar jet, located over the northern U.S., and the subtropical jet, which is blowing over the Gulf of Mexico. As long as the subtropical jet is blowing over the Gulf of Mexico with 30 - 50 knots of wind like it is now, no tropical storm formation is likely in the Gulf. If we do get Tropical Storm Alberto in the next two weeks, it will have to form in the western Caribbean south of Cuba. Steering currents would then likely take the storm north across Cuba and then northeastward across the Bahamas and out to sea. The Gulf Coast from Texas to the Florida Panhandle will be protected from any tropical storms by the strong subtropical jet steam. I'm predicting only a 10% chance of a tropical storm in the Atlantic by June 15 this year.

The GFS model predicts that the subtropical jet will continue to generate high levels of wind shear over the prime June breeding grounds for hurricanes for at least the next 12 days. After that, I suspect the subtropical jet will weaken, and we will get one tropical storm forming in late June over the western Caribbean or Gulf of Mexico.

Vacation
Given that the next two weeks are likely to be the quietest time in what promises otherwise to be another long and busy hurricane season, I'm outta here. This will be my final "live" blog until June 13, as I'm taking my main summer vacation early. I plan to spend some time at Cape Hatteras before any hurricanes threaten! I've prepared a series of "canned" blogs, mainly Q and A from a newspaper interview I did last Sunday for a Florida newspaper. If Alberto does surprise us while I'm gone, the other meteorologists at wunderground will post the latest analysis here for you.

So long!
Jeff Masters

Updated: 8:40 PM GMT on June 27, 2006

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About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.