Heavy snowfall in a warming world
A major new winter storm is headed east over the U.S. today, and threatens to dump a foot or more of snow on Philadelphia, New York City, and surrounding regions Tuesday and Wednesday. Philadelphia is still digging out from its second top-ten snowstorm of recorded history to hit the city this winter, and the streets are going to begin looking like canyons if this week's snowstorm adds a significant amount of snow to the incredible 28.5" that fell during "Snowmageddon" last Friday and Saturday. Philadelphia has had two snowstorms exceeding 23" this winter. According to the National Climatic Data Center, the return period for a 22+ inch snow storm is once every 100 years--and we've had two 100-year snow storms in Philadelphia this winter. It is true that if the winter pattern of jet stream location, sea surface temperatures, etc, are suitable for a 100-year storm to form, that will increase the chances for a second such storm to occur that same year, and thus the odds have having two 100-year storms the same year are not 1 in 10,000. Still, the two huge snowstorms this winter in the Mid-Atlantic are definitely a very rare event one should see only once every few hundred years, and is something that has not occurred since modern records began in 1870. The situation is similar for Baltimore and Washington D.C. According to the National Climatic Data Center, the expected return period in the Washington D.C./Baltimore region for snowstorms with more than 16 inches of snow is about once every 25 years. This one-two punch of two major Nor'easters in one winter with 16+ inches of snow is unprecedented in the historical record for the region, which goes back to the late 1800s.
Figure 1. Car buried in Virginia by "Snowmageddon" on February 8, 2010. Image credit: wunderphotographer Brabus Cave.
Top 9 snowstorms on record for Philadelphia:
1. 30.7", Jan 7-8, 1996
2. 28.5", Feb 5-6, 2010 (Snowmageddon)
3. 23.2", Dec 19-20, 2009 (Snowpocalypse)
4. 21.3", Feb 11-12, 1983
5. 21.0", Dec 25-26, 1909
6. 19.4", Apr 3-4, 1915
7. 18.9", Feb 12-14, 1899
8. 16.7", Jan 22-24, 1935
9. 15.1", Feb 28-Mar 1, 1941
The top 10 snowstorms on record for Baltimore:
1. 28.2", Feb 15-18, 2003
2. 26.5", Jan 27-29, 1922
3. 24.8", Feb 5-6, 2010 (Snowmageddon)
4. 22.8", Feb 11-12, 1983
5. 22.5", Jan 7-8, 1996
6. 22.0", Mar 29-30, 1942
7. 21.4", Feb 11-14, 1899
8. 21.0", Dec 19-20, 2009 (Snowpocalypse)
9. 20.0", Feb 18-19, 1979
10. 16.0", Mar 15-18, 1892
The top 10 snowstorms on record for Washington, D.C.:
1. 28.0", Jan 27-28, 1922
2. 20.5", Feb 11-13, 1899
3. 18.7", Feb 18-19, 1979
4. 17.8" Feb 5-6, 2010 (Snowmageddon)
5. 17.1", Jan 6-8, 1996
6. 16.7", Feb 15-18, 2003
7. 16.6", Feb 11-12, 1983
8. 16.4", Dec 19-20, 2009 (Snowpocalypse)
9. 14.4", Feb 15-16, 1958
10. 14.4", Feb 7, 1936
Heavy snow events--a contradiction to global warming theory?
Global warming skeptics regularly have a field day whenever a record snow storm pounds the U.S., claiming that such events are inconsistent with a globe that is warming. If the globe is warming, there should, on average, be fewer days when it snows, and thus fewer snow storms. However, it is possible that if climate change is simultaneously causing an increase in ratio of snowstorms with very heavy snow to storms with ordinary amounts of snow, we could actually see an increase in very heavy snowstorms in some portions of the world. There is evidence that this is happening for winter storms in the Northeast U.S.--the mighty Nor'easters like the "Snowmageddon" storm of February 5-6 and "Snowpocalypse" of December 19, 2009. Let's take a look at the evidence. There are two requirements for a record snow storm:
1) A near-record amount of moisture in the air (or a very slow moving storm).
2) Temperatures cold enough for snow.
It's not hard at all to get temperatures cold enough for snow in a world experiencing global warming. According to the 2007 Intergovernmental Panel on Climate Change (IPCC) report, the globe warmed 0.74°C (1.3°F) over the past 100 years. There will still be colder than average winters in a world that is experiencing warming, with plenty of opportunities for snow. The more difficult ingredient for producing a record snowstorm is the requirement of near-record levels of moisture. Global warming theory predicts that global precipitation will increase, and that heavy precipitation events--the ones most likely to cause flash flooding--will also increase. This occurs because as the climate warms, evaporation of moisture from the oceans increases, resulting in more water vapor in the air. According to the 2007 Intergovernmental Panel on Climate Change (IPCC) report, water vapor in the global atmosphere has increased by about 5% over the 20th century, and 4% since 1970. This extra moisture in the air will tend to produce heavier snowstorms, assuming it is cold enough to snow. Groisman et al. (2004) found a 14% increase in heavy (top 5%) and 20% increase in very heavy (top 1%) precipitation events in the U.S. over the past 100 years, though mainly in spring and summer. However, the authors did find a significant increase in winter heavy precipitation events have occurred in the Northeast U.S. This was echoed by Changnon et al. (2006), who found, "The temporal distribution of snowstorms exhibited wide fluctuations during 1901-2000, with downward 100-yr trends in the lower Midwest, South, and West Coast. Upward trends occurred in the upper Midwest, East, and Northeast, and the national trend for 1901-2000 was upward, corresponding to trends in strong cyclonic activity."
The strongest cold-season storms are likely to become stronger and more frequent for the U.S.
The U.S. Global Change Research Program (USGCRP) began as a presidential initiative in 1989 and was mandated by Congress in the Global Change Research Act of 1990 (P.L. 101-606), which called for "a comprehensive and integrated United States research program which will assist the Nation and the world to understand, assess, predict, and respond to human-induced and natural processes of global change." This program has put out some excellent peer-reviewed science on climate change that, in my view, is as authoritative as the U.N.-sponsored Intergovernmental Panel on Climate Change (IPCC) reports. In 2009, the USGCRP put out its excellent U.S. Climate Impacts Report, summarizing the observed and forecast impacts of climate change on the U.S. The report's main conclusion about cold season storms was " Cold-season storm tracks are shifting northward and the strongest storms are likely to become stronger and more frequent".
The report's more detailed analysis: "Large-scale storm systems are the dominant weather phenomenon during the cold season in the United States. Although the analysis of these storms is complicated by a relatively short length of most observational records and by the highly variable nature of strong storms, some clear patterns have emerged (Kunkel et al., 2008).
Storm tracks have shifted northward over the last 50 years as evidenced by a decrease in the frequency of storms in mid-latitude areas of the Northern Hemisphere, while high-latitude activity has increased. There is also evidence of an increase in the intensity of storms in both the mid- and high-latitude areas of the Northern Hemisphere, with greater confidence in the increases occurring in high latitudes (Kunkel et al., 2008). The northward shift is projected to continue, and strong cold season storms are likely to become stronger and more frequent, with greater wind speeds and more extreme wave heights". The study also noted that we should expect an increase in lake-effect snowstorms over the next few decades. Lake-effect snow is produced by the strong flow of cold air across large areas of relatively warmer ice-free water. The report says, "As the climate has warmed, ice coverage on the Great Lakes has fallen. The maximum seasonal coverage of Great Lakes ice decreased at a rate of 8.4 percent per decade from 1973 through 2008, amounting to a roughly 30 percent decrease in ice coverage. This has created conditions conducive to greater evaporation of moisture and thus heavier snowstorms. Among recent extreme lake-effect snow events was a February 2007 10-day storm total of over 10 feet of snow in western New York state. Climate models suggest that lake-effect snowfalls are likely to increase over the next few decades. In the longer term, lake-effect snows are likely to decrease as temperatures continue to rise, with the precipitation then falling as rain".
Figure 2. The annual average number of snowstorms with a 6 inch (15.2 cm) or greater accumulation, from the years 1901 - 2001. A value of 0.1 means an average of one 6+ inch snowstorm every ten years. Image credit: Changnon, S.A., D. Changnon, and T.R. Karl, 2006, Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States, J. Applied Meteorology and Climatology, 45, 8, pp. 1141-1155, DOI: 10.1175/JAM2395.1.
More heavy snowstorms occur in warmer-than-average years
Another interesting result from the Changnon et al. (2006) paper (Figure 2) is the relationship between heavy snowstorms and the average winter temperature. For the contiguous U.S. between 1900 - 2001, the authors found that 61% - 80% of all heavy snowstorms of 6+ inches occurred during winters with above normal temperatures. In other words, the old adage, "it's too cold to snow", has some truth to it. The authors also found that 61% - 85% of all heavy snowstorms of 6+ inches occurred during winters that were wetter than average. The authors conclude, "a future with wetter and warmer winters, which is one outcome expected (National Assessment Synthesis Team 2001), will bring more heavy snowstorms of 6+ inches than in 1901 - 2000. The authors found that over the U.S. as a whole, there had been a slight but significant increase in heavy snowstorms of 6+ inches between 1901 - 2000. However, a separate paper by Houston and Changnon (2009), "Characteristics of the top ten snowstorms at First-Order Stations in the U.S.", found that there was no upward or downward trend in the very heaviest snowstorms for the contiguous U.S. between 1948 - 2001, as evaluated by looking at the top ten snowstorms for 121 major cities.
Commentary
One can "load the dice" in favor of events that used to be rare--or unheard of--if the climate is changing to a new state. It is quite possible that nature's weather dice have been loaded in favor of more intense Nor'easters for the U.S. Mid-Atlantic and Northeast, thanks to the higher levels of moisture present in the air due to warmer global temperatures. It's worth mentioning that heavy snow storms should be getting increasingly rare for the extreme southern portion of the U.S. in coming decades. There's almost always high amounts of moisture available for a potential heavy snow in the South--just not enough cold air. With freezing temperatures expected to decrease and the jet stream and associated storm track expected to move northward, the extreme southern portion of the U.S. should see a reduction in both heavy and ordinary snow storms in the coming decades.
The CapitalClimate blog has a nice perspective on "Snowmageddon", and Joe Romm of climateprogress.org has some interesting things to say about snowstorms in a warming climate.
References
Changnon, S.A., D. Changnon, and T.R. Karl, 2006, , "Temporal and Spatial Characteristics of Snowstorms in the Contiguous United States", J. Appl. Meteor. Climatol., 45, 1141.1155.
Groisman, P.Y., R.W. Knight, T.R. Karl, D.R. Easterling, B. Sun, and J.H. Lawrimore, 2004, "Contemporary Changes of the Hydrological Cycle over the Contiguous United States: Trends Derived from In Situ Observations," J. Hydrometeor., 5, 64-85.
Kunkel, K.E., P.D. Bromirski, H.E. Brooks, T. Cavazos, A.V. Douglas, D.R. Easterling, K.A. Emanuel, P.Ya. Groisman, G.J. Holland, T.R. Knutson, J.P. Kossin, P.D. Komar, D.H. Levinson, and R.L. Smith, 2008: Observed changes in weather and climate extremes. In: Weather and Climate Extremes in a Changing Climate: Regions of Focus: North America, Hawaii, Caribbean, and U.S. Pacific Islands [Karl, T.R., G.A. Meehl, C.D. Miller, S.J. Hassol, A.M. Waple, and W.L. Murray (eds.)]. Synthesis and Assessment Product 3.3. U.S. Climate Change Science Program, Washington, DC, pp. 35-80.
Congratulations, New Orleans!
Congratulations to everyone in New Orleans, for the Saints' Super Bowl victory! It's great to the see the city celebrating after enduring so many years of hardship in the wake of Hurricane Katrina.
Jeff Masters
Reader Comments
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 — Blog Index
New errors in IPCC climate change report
The United Nations panel on climate change is facing fresh criticism today as The Sunday Telegraph reveals new factual errors and poor sources of evidence in its influential report to government leaders.... (more)
Would you like more examples..there are hundreds of them. Mellow out a little..and listen to both sides. Its a report..not a bible or Holy Grail.
MEXICO CITY – At least 28 people have died as a result of torrential rains that have affected various parts of central Mexico, especially the capital and the states of Michoacan and Mexico, officials said.
Most of the fatalities have occurred in the central-western state of Michoacan, where 18 people had died as of Friday and the total number of people affected could reach 20,000, authorities said.
Public safety spokespersons in that state said that 10 people were confirmed dead on Friday, adding to the eight deaths registered two days earlier in the towns of Angangueo, Tuxpan and Zitacuaro.
President Felipe Calderon visited Michoacan on Friday and – joined by local authorities – examined the situation caused by the overflowing of the Tuxpan River and the San Pedro dam.
Meanwhile, seven people traveling on a road in the state of Mexico, which surrounds the capital, were killed in a mudslide, local government officials said.
Gov. Enrique Peña Nieto said the mudslide occurred along a stretch of the Toluca-Temascaltepec road and added that 7,000 homes in Mexico state have been affected by flooding.
http://www.laht.com/article.asp?ArticleId=351798&CategoryId=14091
The National Weather Service has posted Winter Storm Warnings for all of Maryland west of the Chesapeake Bay, calling for 10 to 20 inches of new snow by Wednesday evening.
http://weblogs.marylandweather.com/2010/02/storm_warnings_posted_another.html
Scroll scroll scroll scroll scroll scroll scroll thanks for NWS update, Bordo; scroll scroll scroll scroll scroll scroll scroll scroll Grothar, hope your travels were good scroll scroll scroll scroll scroll scroll Tampa Tom, hope you will start a disaster management blog scroll back scroll if you have the fortitude scroll scroll scroll scroll hi Orca, Canadians seem pretty civil scroll scroll scroll scroll scroll Ike, my dogs are having trouble circumnavigating the snow scroll scroll scroll scroll scroll see you another time, maybe...
Tell me what the world looked like when the trees grew on the northern Greenland coast. Or what the ice looked like when the bugs, flora and fauna they found in ice core mud (DNA verified) were present in south central greenland. It seems I cannot get an answer from anyone on that.....
ROFLMAO... post of the day :)
Pretty much the story for 2/8/2010 on the WU blog...
Well said.
The Knickerbocker Snowstorm of
January 27-28, 1922
Washington's largest snowstorm on record began during the evening of January 27, 1922. By the morning of January 28, the snow total had reached 18 inches. By mid-afternoon, the accumulation reached a depth of 25 inches. The snow did not stop until the morning of January 29, with an official snow depth of 28 inches, a single storm snowfall record for Washington, D.C. that still stands today. A snow depth of 33 inches was measured in Rock Creek Park, three miles to the north of Washington%u2019s official weather station. Temperatures were in the low-to-mid-20's during most of the storm. The liquid total of the snowfall was 3.02 inches.
The weight of the record-breaking snow collapsed the roof of the Knickerbocker Theater. The roof of the theater fell on scores of moviegoers, killing 98 and injuring 133. The disaster ranks as one of the worst in Washington's history.
The storm responsible for the record snowfall formed east of South Carolina on the morning of January 27 and moved slowly north to a position well east of Cape Hatteras on the morning of January 28. It then drifted slowly east-northeast out to sea. A stationary high-pressure system north of New York State ensured that temperatures remained cold throughout the event.
An account of the collapse of the Knickerbocker Theatre is as follows:
On the evening of January 28, 1922 several hundred people fought their way through a massive snowstorm to see the show at the Knickerbocker Theatre, Washington's largest and most modern moving picture theater of the time. When the show began that evening, the greatest snowstorm in Washington's history was winding down. It had already dumped over two feet of heavy, wet snow on the city and many flat-roofed buildings, like that of the Knickerbocker Theater, were tremendously burdened by the weight.
Shortly before 9:00 p.m., the Knickerbocker Theaters orchestra was playing for intermission. The lights had dimmed and the people were returning to their seats. Suddenly, a loud hissing noise filled the room. The ceiling, weighed down from the snow, had begun to split apart down the middle. The few people who had noticed the splitting ceiling dove under their seats or ran for the door. Within seconds, the entire roof started to fall towards the crowd. As the roof came down, it collapsed the theater's cement balcony and pulled down portions of the theaters brick wall. Concrete, bricks and metal crashed to the ground, burying dozens of people.
George Brodie had entered the theater moments before the roof collapsed and gave the following account: I grabbed for my hat and coat, and the next minute found myself flat on my face with something weighty on top. I lay still for about five minutes when I noticed at the side of me a girl with an arch or pillar resting upon her. I tried to pull it off but couldn't move it. Then I started working my way slowly in some direction I think the middle and with four other fellows we saw a hole with a light shining through. The next thing I know I was on the street, but I don't know how I got there. I stayed around for a while and helped several others, who were apparently uninjured, out of the place. It was a frightful sight within, nothing but moans, cries and darkness.
The scene after the disaster was terrible. People ran through the ruins calling for missing loved ones. Shouts from rescue workers mixed with the cries of anguish from victims buried under the wreckage. Lanterns and shadows could be seen darting about through the heavily falling snow. Great masses of twisted steel, splintered timber and crumbled masonry covered the floor of the theater. One reporter wrote that no description of the scene could convey the awfulness of what he had witnessed that night. Another reporter, with recent memories of the devastation of World War I in mind, wrote, Stark and grim as any ruin in the war-swept area of France or Belgium stood the walls of the Knickerbocker theater.
The chaotic rescue effort became better organized when the police and firemen arrived at the scene. Police lines were drawn and heavy equipment was called in. By 12:00 a.m., 200 police, soldiers and firemen were working feverishly, digging through the wreckage. By 2:30 a.m., over 600 rescue workers were on the scene. Residents in the vicinity of the theater supplied hot food and coffee to the rescuers. One small boy was even sent into the wreckage, squeezing through the holes between the fallen concrete slabs, to distribute pain pills to those who were trapped under the rubble.
The rescue workers had to dig through two layers of debris to rescue the injured. First they had to remove the plaster and steel of the roof to reach the injured that had been seated in the balcony. Large saws were used to cut through the roofs heavy wire screen that had once held the ceilings plaster. After the roof had been removed, the workers had to chisel through the cement structure of the balcony to rescue those who had been seated on the first floor. The rescue effort was not completed until the following afternoon.
The toll for the disaster was 98 dead and 133 injured. Every hospital in the area was filled with the injured. Many stores and houses served as short-term first-aid stations. Hotels opened their doors to the injured as well as the rescuers. The disaster ranks as one of the worst in Washington's history. The snowstorm still ranks as Washington's largest single snowfall.
http://abclocal.go.com/kabc/story?section=weather&id=7264666
With another storm barreling eastward, Philly prepares for its snowiest winter on record
http://www.latimes.com/news/nationworld/nation/wire/sns-ap-us-winter-weather-philadelphia,0,5044254 .story
Another storm brings snow, wind to Iowa
http://www.chicagotribune.com/news/chi-ap-ia-winterstorm-iowa,0,3404656.story
Two Excedrin, please...
hopefully AGW free posts will help
There is not a SINGLE person on this whole blog (that I know of) that does not think Climate Change is happening.
Its the reason (Natural/Man made/Both) that is in question. I personally believe its a little of both... but more to the natural side of the equation You obviously believe that its entirely manmade... I disagree.
But I am not going to try and public flog you or belitte your beliefs in a friendly blog. You on the other hand believe that people either have to think exactly your way..or they are obviously moronic half wits.
I can think of a few other people in History who had the same beliefs such as yourself.
Now off the soapbox and shields up :)
I don't think anyone will take you up on that bet... since you would win.
"LONG TERM...[THURSDAY THROUGH SUNDAY]...NO CHANGES, JUST COMMENTARY
ON THE 12Z OUTPUT. GFS SHOWS SOME MODERATION OF THE POSITIONS OF THE
5400 AND 1290 M THICKNESS ISOHYETS FOR 1000-500 AND 1000-850 MB
RESPECTIVELY. 12 Z GFS SHOWS A SLIGHT NORTHWARD TRACK TREND FROM THE
06Z GFS BUT LONGER TERM TRENDS MUST BE ESTABLISHED. IT SHOULD ALSO BE
NOTED THE SNOWPACK LEFT OVER FROM THE SNOWFALL LAST WEEKEND MAY
PRESENT A SHIFT IN THE THICKNESS GRADIENT MAXIMUM SOMEWHAT SOUTHEAST.
THAT WOULD ALSO AFFECT THE PROSPECT OF A WINTRY MIX OR ALL SNOW EVENT
IN THIS REGION. COUNTERING FACTORS ARE INCREASING SUN ANGLE AND
ADIABATIC COMPRESSION AND WARMING IN THE LAGRANGIAN FRAME OF
REFERENCE. STAY TUNED."
well there was definitely more snow with this most recent storm, with some places having 40 inches
drg had stated that it was a pollutant in that sense. With a medical pic and all. I simply called him on it.
How sure are you that they're wrong? How did you come by this information? Did you check the math?
That was a very slow moving storm with enormous totals. It moved from the South all the way up the coast rather than this last one coming from the south and west. Covered a much larger area. The reason totals were so high, was the slowness of the storm.
Hmm be nice flood... BTW... it rained the other day.. we might have some mushrooms you will remember from your youth :)
Wait it out and pray for better weather - beside all the brightest mind urge us to act now and reduce those greenhouse gases.
dont misinterpret me please. I wasnt agreeing with one side or the other, just stating that if we have blogs that are strictly weather based, then there would be less fighting and bickering
8-14 day temperature outlook...
LOL. GREAT post!
I didn't get you wrong; I was making a point...I like you and respect your opinions because you are typically an evenly balanced person. The issue is that the Doc posted climate change info today, so naturally that sparked some debate...as I said before, the extremistys on either side of this are what makes it ugly...that does not include you, by the way LOL
The link to my blog is a graph animation that I created. Sources provided at the bottom. The graphs represents that.
Anyone is free to double-check it, but it is just a data representation and can be fully recreated from the raw data by anyone who so chooses.
Completely objective. No opinion on that blog at all. I'll usually state "imo" if I am opining, but I generally shy away from that when it comes to this topic lately.
Actually why I created the animations blog, actually. Purely objective and folks take it fwiw to them.
That is why I found your accusation strange. I generally don't post opinion, and am pretty sure I haven't much lately, with maybe a few exceptions.
I will call someone out if they are posting false information, such as CO2 is a pollutant outside the AGW debate. ;)
ah ok, gotcha!
I like you too :P haha
I'm going to go out on a limb, and say its going to be cold next week in the SE.
That's exactly what they want to do to us
Washington DC is starting to dig itself out from under yesterday's record snowfall but 100,000 homes in the region are still without power.
The US capital is still crippled by the massive snowfall, which dumped 60 to 100 centimetres of snow across America's mid-Atlantic.
Icy conditions and freezing winds are not helping efforts to clear roads and repair broken power lines.
Major cities are effectively shut down, public transport services have been suspended and authorities are appealing to people to stay off the roads.
Forecasters say the wind chill and icy conditions mean the snow is not going anywhere in a hurry.
Another 30 centimetres of snow is expected to fall by Wednesday.
Officials are considering opening shelters for thousands of families who have no means of keeping warm.
- ABC
I'm not sure who is more alarmist... you, or the people you oppose.
The Sydney Catchment Management Authority says the city's dam levels have risen by five per-cent as a result of the rainfall over recent days.
The Authority says Warragamba Dam has risen 1.7 metres and overall dam levels are at 55 per-cent.
General manager of water supply Ian Tanner says for a change the catchment received as much rain as the Sydney CBD.
"Particularly in the Blue Mountains they received an incredible amount of water, he said"
"And our dam as of this morning has risen almost 5 per cent, in terms of how much water that is, that's an extra 3 months supply just in the last few days."
The State Opposition says the recent heavy rainfall shows the State Government jumped the gun by building Sydney's desalination plant.
The Acting Opposition Leader Andrew Stoner says the Coalition always favoured recycling and stormwater harvesting and the recent rainfall vindicates this stance.
"The question many Sydney families will be asking though is why have we got to pay the price of a two billion dollar desalination plant when there is water, water everywhere, that's free water from the sky."
- ABC
Yep..
Tropical Disturbance Advisory #5
TROPICAL CYCLONE PAT (09F)
6:00 AM FST February 9 2010
======================================
A TROPICAL CYCLONE ALERT IS NOW IN FORCE FOR SOUTHERN COOKS.
At 18:00 PM UTC, Tropical Cyclone Pat (985 hPa) located at 14.0S 159.6W has 10 minute sustained winds of 50 knots. The cyclone is reported as moving southeast at 11 knots. Position FAIR based on GOES visible/enhanced infrared radar imagery with animation.
Storm Force Winds
=================
30 NM of the center
Gale Force Winds
===============
120 NM of the center in sectors from northeast through southeast to southwest and within 60 NM elsewhere
The low level circulation center located under persistent deep convection within central dense overcast. Overall organization remains good. Primary band re-organizing while wrapping around low level circulation center. Outflow improving to north and south. TC PAT lies in a diffluent region aloft in a low shear environment.
Dvorak analysis based on 0.8 wrap on LOG 10 spiral, yielding DT=3.5
Dvorak Intensity: T3.5/3.5/D1.5/24HRS.
System is currently steered southeast by northwest deep layer mean. A turn to the west in the next 12-18 hours will bring the cyclone into arae of strengthening shear. Global models generally agree on a southeast and then southwest movement with brief intensification before weakening.
Forecast and Intensity
======================
12 HRS: 15.1S 159.2W - 50 knots (CAT 2)
24 HRS: 15.8S 159.3W - 50 knots (CAT 2)
48 HRS: 17.1S 161.5W - 35 knots (CAT 1)
The next Tropical Disturbance Advisory on TC PAT will be issued at around 2:30 AM UTC (Tuesday)..
There will be a saturated dendritic growth zone with good thermal profile and omega forcing.
Scientists have discovered a link between drought in the south-west of Western Australia and increased snowfall in Antarctica.
Doctor Tas van Ommen from the Australian Antarctic Division says there is a pattern of atmospheric circulation that moves moist warm air from the Tasman Sea, near New Zealand, to East Antarctica.
Dr van Ommen says the same pattern is part of a larger flow recirculating dry, cool air from Antarctica to the south of Western Australia.
"So, what's happened is we're getting more air being driven southwards from the Tasman Sea region onto coastal Antarctica and at the same time that same pattern is driving cold, dry air north to Western Australia."
"It's that cold, dry air that's actually interfering with the normal winter rainfall and we believe responsible for at least part of the drought."
Dr van Ommen says modelling shows the dry spell over WA is set to continue.
"My colleagues at CSIRO and the Bureau of Meteoroloy have been commenting on our work and the opinion I've heard them put is that they are predicting sustained drought. We want to help make sure that they are getting those projections right."
- ABC
______________________________________________________________________________________________
Antarctic snow linked to WA dry
Scientists have discovered a link between the ongoing drought in the south western corner of Australia and increased snowfall in parts of Antarctica.
Dr Tas van Ommen of the Australian Antarctic Division (AAD) says ice core samples taken from Law Dome in East Antarctica show an unusual and consistent increase in snowfall since the late 1960s.
Reporting in Nature Geoscience van Ommen says, "after examining 750 years worth of samples, the increase is well above the normal sort of variability one expects."
The work was part of efforts to better understand Antarctica's climate history.
van Ommen and AAD colleague Dr Vin Morgan found the cause was a pattern of atmospheric circulation that brings warm, moist air from the Tasman Sea near New Zealand to East Antarctica.
He says "further research found this same pattern was part of a larger flow recirculating dry, cool air from the Antarctic to south western Australia."
And a check of Western Australian climate records showed a very strong correlation.
"The more it snowed at Law Dome, the more intense the drought became in the south west of Western Australia."
van Ommen says "the cause appears to be what's called the 'wave three pattern' in the high latitude atmosphere which is associated with the three southern hemisphere ocean basins, the Pacific, Atlantic and Indian.
"But as to why the wave three pattern has strengthened over the last 30 years, that's still a mystery," says van Ommen.
Climate change models that factor in increases in CO2 emissions and ozone depletion appear to produce a similar result, a finding backed up by climatologist Tim Cowan of the CSIRO.
"Not only has the paper established a nice link between the snowfall and drought, but the climate models show increases in greenhouse gases and an ozone reduction can account for about half the rainfall decline in Western Australia's southwest," says Cowan.
"We have seen a real step change in rainfall levels in Western Australia's south west, which is very dramatic and concerning."
Cowan says, "based on climate models projections for future, there's a high probability that south west Western Australia will get even dryer.
- ABC
and if both sides of the AGW issue had nukes, they would both use them to kill us all ,to feed their ego.....
Viewing: 501 - 551
Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 — Blog Index