CSU predicts highly active hurricane season; Cyclone Phet approaching Oman

By: Dr. Jeff Masters , 2:00 PM GMT on June 03, 2010

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A very active Atlantic hurricane season is on tap for 2010, according to the seasonal hurricane forecast issued June 2 by Dr. Phil Klotzbach and Dr. Bill Gray of Colorado State University (CSU). The CSU team is calling for 18 named storms, 10 hurricanes, and 5 intense hurricanes, and an Accumulated Cyclone Energy (ACE) 185% of average. Between 1950 - 2000, the average season had 10 named storms, 6 hurricanes, and 2 intense hurricanes. But since 1995, the beginning of an active hurricane period in the Atlantic, we've averaged 14 named storms, 8 hurricanes, and 4 intense hurricanes per year. The new forecast is a step up from their April forecast, which called for 15 named storms, 8 hurricanes, and 4 intense hurricanes. The new forecast calls for a much above-average chance of a major hurricane hitting the U.S., both along the East Coast (51% chance, 31% chance is average) and the Gulf Coast (50% chance, 30% chance is average). The risk of a major hurricane in the Caribbean is also high, at 65% (42% is average.) This is the most aggressive early June forecast ever issued by the CSU group; the previous most aggressive such forecasts were for the 2006 and 2007 seasons, when the CSU team predicted 17 named storms, 9 hurricanes, and 5 intense hurricanes. Both of these forecasts did poorly, particularly the 2006 forecast, as only 10 named storms, 5 hurricanes, and 2 intense hurricanes were observed.

The forecasters cited four main reasons for an active season:

1) Weak La Niña conditions should develop by the most active portion of this year's hurricane season (August-October). The expected trend towards weak La Niña conditions should lead to reduced levels of vertical wind shear compared with what was witnessed in 2009.

2) Current SST anomalies are running at near-record warm levels. These very warm waters are associated with dynamic and thermodynamic factors that are very conducive for an active Atlantic hurricane season.

3) A weaker-than-normal Azores High prevailed during April-May. Weaker high pressure typically results in weaker trade winds that are commonly associated with more active hurricane seasons.

4) We are in the midst of a multi-decadal era of major hurricane activity, which began in 1995. Major hurricanes cause 80-85 percent of normalized hurricane damage.

Analogue years
The CSU team picked four previous years when atmospheric and oceanic conditions were similar to what we are seeing this year: weak El Niño to neutral conditions, well above-average tropical Atlantic SSTs, and above-average far North Atlantic SSTs during April - May. Those four years were 2005, the worst hurricane season of all time; 1969, the 3rd worst hurricane season of all time, featuring Category 5 Hurricane Camille which hit Mississippi; 1966, a relatively average year that featured Category 4 Inez that killed 1,000 people in Haiti; and 1958, a severe season with 5 major hurricanes. The mean activity for these five years was 17 named storms, 10 hurricanes, and 5 intense hurricanes, almost the same as the 2009 CSU forecast.

How accurate are the June forecasts?
The June forecasts by the CSU team over the past 12 years have had a skill 19% - 30% higher than a "no-skill" climatology forecast for number of named storms, number of hurricanes, and the ACE index (Figure 1). This is a decent amount of skill for a seasonal forecast, and these June forecasts can be useful to businesses such as the insurance industry and oil and gas industry that need to make bets on how active the coming hurricane season will be. Unfortunately, the CSU June 1 forecasts do poorly at forecasting the number of major hurricanes (only 3% skill), and major hurricanes are what do 80 - 85% of all hurricane damage (normalized to current population and wealth levels.) This year's June forecast uses the same formula as the past two years, which did quite well predicting the 2008 hurricane season (prediction: 15 named storms, 8 hurricanes, 4 intense hurricanes; observed: 16 named storms, 8 hurricanes, 5 intense hurricanes) and 2009 hurricane season (prediction: 11 named storms, 5 hurricanes, 2 intense hurricanes; observed: 9 named storms, 3 hurricanes, 2 intense hurricanes.) An Excel spreadsheet of their forecast skill (expressed as a mathematical correlation coefficient) show values from 0.44 to 0.58 for their June forecasts, which is respectable.


Figure 1. Comparison of the percent improvement over climatology for May and August seasonal hurricane forecasts for the Atlantic from NOAA, CSU and TSR from 1999-2009 (May) and 1998-2009 (August), using the Mean Squared Error. The British firm Tropical Storm Risk (TSR) will issue their outlook for the 2010 Atlantic hurricane season on June 4. Image credit: Verification of 12 years of NOAA seasonal hurricane forecasts, National Hurricane Center.

NOAA's 2010 hurricane season forecast
NOAA issued their forecast for the upcoming Atlantic hurricane season last week. As I discussed in my post on their forecast, NOAA is calling for very active and possibly hyperactive season. They give an 85% chance of an above-normal season, a 10% chance of a near-normal season, and just a 5% chance of a below-normal season. NOAA predicts a 70% chance that there will be 14 - 23 named storms, 8 - 14 hurricanes, and 3 - 7 major hurricanes, with an Accumulated Cyclone Energy (ACE) in the 155% - 270% of normal range. If we take the midpoint of these numbers, NOAA is calling for 18.5 named storms, 11 hurricanes, 5 major hurricanes, and an ACE index 210% of normal. A season with an ACE index over 175% is considered "hyperactive."


Figure 2. Visible satellite image of Tropical Cyclone Phet on Thursday, June 3, 2010.

Tropical Cyclone Phet the 2nd strongest Arabian Sea storm on record
Record heat over southern Asia in May has helped heat up the Arabian Sea to 2°C above normal, and the exceptionally warm SSTs helped fuel Tropical Cyclone Phet into the second strongest tropical cyclone ever recorded in the Arabian Sea. Phet peaked at Category 4 strength with 145 mph winds yesterday, and has weakened slightly to 135 mph winds this morning. Only Category 5 Cyclone Gonu of 2007, which devastated Oman, was a stronger Arabian Sea cyclone.

Phet is over very warm waters of 30 - 31°C, and is under moderate wind shear of 10 - 20 knots. However, the storm is wrapping in dry air from the Arabian Peninsula, which has caused weakening. Visible satellite imagery from this morning (Figure 2) shows that the heavy thunderstorms on the north side of Phet have been eroded away by dry air. Phet is a small storm, and could fall apart fairly quickly if dry air can penetrate into its core. This should happen later today, since wind shear is on the increase, and the shearing winds should be able to disrupt the circulation enough that dry air can force its way into Phet's eyewall. Phet is fairly small, will miss the most heavily populated areas of Oman, and will likely undergo significant weakening before landfall, so the storm is unlikely to cause the kind of catastrophic flooding that Category 5 Cyclone Gonu of 2007 brought to Oman. Gonu killed 50 people and did $4.2 billion in damage. Phet's heaviest rains will be confined to a relatively sparsely populated region of Oman's coast. Rainfall amounts in excess of 6 inches in 18 hours (Figure 3) can be expected along Oman's coast today, which will likely cause extreme flooding.

After Phet's encounter with Oman, the storm will probably be at tropical storm strength when it makes its second landfall in Pakistan. Heavy rains from Phet will be the major danger for Pakistan, and serious flooding can be expected over southern Pakistan.


Figure 3. Forecast rain amounts for the 18-hour period ending at 2am EDT June 3, 2010. Image credit: NOAA/NESDIS.

Oil spill update
Onshore winds out of the south, southwest, or west are expected to blow over the northern Gulf of Mexico over most of the next week, resulting increased threats of oil to Alabama, Mississippi, and the Florida Panhandle, according to the latest trajectory forecasts from the State of Louisiana. The latest ocean current forecasts from the NOAA HYCOM model show that these winds will generate a 0.5 - 1 mph current flowing from west to east along the Florida Panhandle coast Sunday and Monday. If this current develops as predicted, it will be capable of bringing light amounts of oil as far east as Fort Walton Beach, Florida, by Monday. If you spot oil, send in your report to http://www.gulfcoastspill.com/, whose mission is to help the Gulf Coast recovery by creating a daily record of the oil spill.

Oil spill resources
My post, What a hurricane would do the Deepwater Horizon oil spill
My post Wednesday with answers to some of the common questions I get about the spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

I'll be back Friday with an analysis of the new TSR hurricane forecast and a new forecast by a promising Florida State University model.

Jeff Masters

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1131. xcool
"I Remember" Tropical Storm Beryl 1988
Member Since: September 26, 2009 Posts: 2 Comments: 15620
Quoting extreme236:


Maybe in this case people just want to see the oil spill mess cleaned up and stopped without all the politics in it. At this point its all on BP to fix it.


It's on BP to fix it, but what about being proactive and making sure we limit the amount of damage done to our coastlines? It doesn't seem like he's too concerned with that to me. Florida politicians of all parties are complaining about it. He's had no real concern until recently. I say this as someone who donated a heck of a lot of time and money to his campaign in 2008.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
If u go by my outlook for this year,,(which has a grain of salt added) Im goin with 20, 10, 5 ... heres my break down...June 1 named,,,July 3 named,,,August 4 named Sept. 7 named october 4 named and Nov. 1...Just a guess mind you,,,but with tropical meterology sometimes it boild down to best guesses right??
Member Since: Posts: Comments:
Quoting KoritheMan:


It can happen, it's just rare.

http://en.wikipedia.org/wiki/1988_Atlantic_hurricane_season's Beryl formed over southeastern Louisiana. Granted, it no doubt had assistance from Lake Pontchartrain, and it was a small enough system so that that made a significant difference in aiding in its genesis.

But it does happen.


Wow thats one of the odder things I've seen in a while, although I guess I can understand it given how swamppy that region is.
Member Since: May 27, 2009 Posts: 0 Comments: 4436
1127. xcool
KoritheMan thanks for posting
Member Since: September 26, 2009 Posts: 2 Comments: 15620
Although the area of disturbed weather around 9˚N 51˚N looks good on visible it looks rather poor on satellite. Expect this to bring some rain to the southern Antilles and Guyana in the next 72 hours. I do not expect development.

Member Since: September 2, 2009 Posts: 130 Comments: 21091
Quoting louisianaboy444:
Hey Kori have you looked at the wave near 50W 850mb vorticity is increasing because of upper divergence exceeding lower convergence which signals a strengthening low pressure area...it appears it could break out the ITCZ if nothing else seeing waves of this magnitude this early is impressive


Yeah I have. I don't believe that any development will come of it, at least in the EATL, but you're correct; it's certainly impressive for early June, and waves like this are in fact more typical of August. A harbinger of things to come, perhaps?

To my knowledge, the only way it could break from the ITCZ is for it to develop a closed surface circulation. IIRC, breaking from the ITCZ doesn't necessarily require latitude.
Member Since: March 7, 2007 Posts: 552 Comments: 19871
1124. NRAamy
1096. TampaSpin 4:29 PM PDT on June 03, 2010
I'm still awaiting for the purple colors to start with the Aliens to come from the deep!


here I am! rock you like a hurricane!

;)
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1122. xcool



Member Since: September 26, 2009 Posts: 2 Comments: 15620
Quoting Levi32:
Good evening everyone.


Evening
Member Since: July 24, 2005 Posts: 407 Comments: 19076
rains along florida's westcoastline should get some heavy rains overnight,IMO
Member Since: Posts: Comments:
Id imagine the drought in Louisiana and Texas is subsiding with all this rain.
Member Since: May 27, 2009 Posts: 0 Comments: 4436
Here's a link to an animation of how this is supposed to work. The first 45 seconds appear to be "stuck", but then it starts giving information...

LMRP Operation
Member Since: Posts: Comments:
Quoting CaneWarning:


They were saying the same thing on the CBS News tonight. If he was GWB, the press would be all over it.


Maybe in this case people just want to see the oil spill mess cleaned up and stopped without all the politics in it. At this point its all on BP to fix it.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Anything that borders its periphery will likely head towards Florida, let's hope that pattern changes.


Why Florida? Pretty much can go anywhere in the W ATL with that set-up.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting MrstormX:
Lol TC formation over land, what a joke.


It can happen, it's just rare. 1988's Beryl formed over southeastern Louisiana. Granted, it no doubt had assistance from Lake Pontchartrain, and it was a small enough system so that that made a significant difference in aiding in its genesis.

But it does happen.
Member Since: March 7, 2007 Posts: 552 Comments: 19871
Quoting IKE:
Latest Rolling Stone magazine hammering Obama(whom they supported), in an editorial...saying....

"But faced with the oil spill unfolding in the Gulf, the president has failed to take the kind of dramatic action required of a true leader."....written by Jann S. Wenner


They were saying the same thing on the CBS News tonight. If he was GWB, the press would be all over it.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
1113. xcool

blob at 10N, 50W



Interesting
Member Since: September 26, 2009 Posts: 2 Comments: 15620
1112. Patrap


Problems encountered trying to place cap on spill
Member Since: July 3, 2005 Posts: 420 Comments: 127512
Hey Kori have you looked at the wave near 50W 850mb vorticity is increasing because of upper divergence exceeding lower convergence which signals a strengthening low pressure area...it appears it could break out the ITCZ if nothing else seeing waves of this magnitude this early is impressive
Member Since: Posts: Comments:
Quoting Weather456:
High set up for the next 2 weeks in June, which basically, much of what's left of the month.

Anything that borders its periphery will likely head towards Florida, let's hope that pattern changes.
Member Since: September 2, 2009 Posts: 130 Comments: 21091
I can't believe they did not think of this Hose problem......WOW!
Member Since: September 2, 2007 Posts: 178 Comments: 20439
Lol TC formation over land, what a joke.
Member Since: May 27, 2009 Posts: 0 Comments: 4436
1098. gulfcoastdweller 11:30 PM GMT on June 03, 2010
Quoting Nolehead:
1086. IKE 11:26 PM GMT on June 03, 2010
Latest Rolling Stone magazine hammering Obama(whom they supported), in an editorial...saying....

"But faced with the oil spill unfolding in the Gulf, the president has failed to take the kind of dramatic action required of a true leader."....written by Jann S. Wenner

might just be the best article of the year....



it makes you wonder what he will we do when someone gets slammed by a hurricane.......things that make you go hummmmm



probably...."nothing to see here please look the other way...it's Bush's fault"
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1105. Levi32
Good evening everyone.
Member Since: November 24, 2005 Posts: 635 Comments: 26547
1104. Patrap


Rescued turtles fighting for their lives

The Gulf of Mexico is home to 5 species of sea turtles - all of them endangered. Now search crews have stepped up efforts to rescue them from the oil and bring them to shore.
Member Since: July 3, 2005 Posts: 420 Comments: 127512
1103. Patrap
Oilzilla continues to grow...

Gulf Oil Spill 2010 Projected Trajectory

Member Since: July 3, 2005 Posts: 420 Comments: 127512
1102. xcool



ok now
Member Since: September 26, 2009 Posts: 2 Comments: 15620
Looks like here we go......OH BOY!
Member Since: September 2, 2007 Posts: 178 Comments: 20439
1099. pottery
On one of the CNN feeds they were showing a close-up of a damaged hose. Hope it's not needed to haul everything back to the surface.........
Member Since: October 24, 2005 Posts: 0 Comments: 23991
I'm still awaiting for the purple colors to start with the Aliens to come from the deep!
Member Since: September 2, 2007 Posts: 178 Comments: 20439
I'm very thankful for decent bandwidth connection... watching three video feeds, and dropping here also.
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1094. xcool
next couple of weeks.first storm
btwntx08
Member Since: September 26, 2009 Posts: 2 Comments: 15620
Quoting stormhank:
I noticed on the AVN shear charts that most of atlantic basin thru sunday has favorable wind shear,,, exceptions bahamas n northern gulf coast....must be some kinda persistant jet in those areas???


It's called the subtropical jet. It's typical for June.
Member Since: March 7, 2007 Posts: 552 Comments: 19871
1086. IKE 11:26 PM GMT on June 03, 2010
Latest Rolling Stone magazine hammering Obama(whom they supported), in an editorial...saying....

"But faced with the oil spill unfolding in the Gulf, the president has failed to take the kind of dramatic action required of a true leader."....written by Jann S. Wenner


might just be the best article of the year....
Member Since: Posts: Comments:
Quoting pottery:
I can hear the guys on the controls
"Not that line you fool the middle one the one next to the one over there OH Crap look out we are all entangled back off go forward you are in my way"


lmao
Member Since: March 7, 2007 Posts: 552 Comments: 19871
Quoting Weather456:
High set up for the next 2 weeks in June, which basically, much of what's left of the month.



That's going to cause a significant warming across the Caribbean and Gulf.
Member Since: March 7, 2007 Posts: 552 Comments: 19871
1087. pottery
I can hear the guys on the controls
"Not that line you fool the middle one the one next to the one over there OH Crap look out we are all entangled back off go forward you are in my way"
Member Since: October 24, 2005 Posts: 0 Comments: 23991
1086. IKE
Latest Rolling Stone magazine hammering Obama(whom they supported), in an editorial...saying....

"But faced with the oil spill unfolding in the Gulf, the president has failed to take the kind of dramatic action required of a true leader."....written by Jann S. Wenner
Member Since: June 9, 2005 Posts: 23 Comments: 37858
I noticed on the AVN shear charts that most of atlantic basin thru sunday has favorable wind shear,,, exceptions bahamas n northern gulf coast....must be some kinda persistant jet in those areas???
Member Since: Posts: Comments:
Quoting Ossqss:


It is interesting that the operators are using a PC in a very similar way, but have joysticks. Video game like. I guess that is a long answer for Yes :)

Thanks again for your help on with the contest stuff!


No problem, was interested to see how it was distributed.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.