Causes of the Russian heat wave and Pakistani floods
The Great Russian Heat Wave of 2010 is one of the most intense, widespread, and long-lasting heat waves in world history. Only the European heat wave of 2003, which killed 35,000 - 50,000 people, and the incredible North American heat wave of July 1936, which set all-time extreme highest temperature records in fifteen U.S. states, can compare. All of these heat waves were caused by a highly unusual kink in the jet stream that remained locked in place for over a month. The jet stream is an upper-level river of air, between the altitudes of about 30,000 - 40,000 feet (10,000 - 12,000 meters). In July over Europe and Asia, the jet stream has two branches: a strong southern "subtropical" jet that blows across southern Europe, and a weaker "polar" jet that blows across northern Europe. The polar jet stream carries along the extratropical cyclones (lows) that bring the mid-latitudes most of their precipitation. The polar jet stream also acts as the boundary between cold, Arctic air, and warm tropical air. If the polar jet stream shifts to the north of its usual location, areas just to its south will be much hotter and drier than normal. In July 2010, a remarkably strong polar jet stream developed over northern Europe. This jet curved far to the north of Moscow, then plunged southwards towards Pakistan. This allowed hot air to surge northwards over most of European Russia, and prevented rain-bearing low pressure systems from traveling over the region. These rain-bearing low pressure systems passed far to the north of European Russia, then dove unusually far to the south, into northern Pakistan. The heavy rains from these lows combined with Pakistan's usual summer monsoon rains to trigger Pakistan's most devastating floods in history.
Figure 1. Winds of the jet stream at an altitude of 300 millibars (roughly 30,000 feet high). Left: Average July winds from the period 1968 - 1996 show that a two-branch jet stream typically occurs over Europe and Asia--a northern "polar" jet stream, and a more southerly "subtropical" jet stream. Right: the jet stream pattern in July 2010 was highly unusual, with a very strong polar jet looping far to the north of Russia, then diving southwards towards Pakistan. Image credit: NOAA/ESRL.
What caused this unusual jet stream pattern?
The unusual jet stream pattern that led to the 2010 Russian heat wave and Pakistani floods began during the last week of June, and remained locked in place all of July and for the first half of August. Long-lived "blocking" episodes like this are usually caused by unusual sea surface temperature patterns, according to recent research done using climate models. For example, Feudale and Shukla (2010) found that during the summer of 2003, exceptionally high sea surface temperatures of 4°C (7°F) above average over the Mediterranean Sea, combined with unusually warm SSTs in the northern portion of the North Atlantic Ocean near the Arctic, combined to shift the jet stream to the north over Western Europe and create the heat wave of 2003. I expect that the current SST pattern over the ocean regions surrounding Europe played a key role in shifting the jet stream to create the heat wave of 2010. Note that the SST anomaly pattern is quite different this year compared to 2003, which may be why this year's heat wave hit Eastern Europe, and the 2003 heat wave hit Western Europe. Human-caused climate change also may have played a role; using climate models, Stott et al. (2004) found it very likely (>90% chance) that human-caused climate change has at least doubled the risk of severe heat waves like the great 2003 European heat wave.
Figure 2. A comparison of the departure of sea surface temperature (SST) from average just prior the the start of the great European heat waves of 2003 and 2010. Temperatures in the Mediterranean Sea were up to 4°C above average in 2003, which has been implicated as a major cause of the Western European heat wave of 2003. Image credit: NOAA/NESDIS.
References
Feudale, L., and J. Shukla (2010), "Influence of sea surface temperature on the European heat wave of 2003 summer. Part I: an observational study", Climate Dynamics DOI: 10.1007/s00382-010-0788-0
Stott, P.A., Stone, D.A., and M.R. Allen (2004), "Human contribution to the European heatwave of 2003", Nature 432, 610-614 (2 December 2004) | doi:10.1038/nature03089. (Here is a free version of the paper, presented at a conference.)
The World Meteorological Organization (WMO) has posted an analysis of the recent extreme weather events, concluding, "the sequence of current events matches IPCC projections of more frequent and more intense extreme weather events due to global warming."
See also my posts, The Great Russian Heat Wave of 2010: 102°F in Moscow and, Over 15,000 likely dead in Russian heat wave; Asian monsoon floods kill hundreds more.
Moscow sees real relief from the Great Russian Heat Wave of 2010
For the first time in more than a month, temperatures at Moscow's Domodedovo airport failed to exceed 30°C (86°F) today. Clouds and thunderstorms blew into the city this morning, keeping the high temperature down to just 29°C (84°F). This breaks a string of 35 straight days when the temperature reached 30°C. At Moscow's official observing site, the Moscow Observatory, this string was 30 days. Moscow's average high temperature for August 13 is 20°C (68°F), so today's temperatures were still well above normal. However, today's cool-down marks the beginning of the end for Russia's great heat wave. The latest forecast for Moscow calls for high temperatures below 30°C for the coming week, and Moscow may not exceed that threshold for the remainder of summer. Long range forecasts from the ECMWF and GFS models continue to suggest that a series of troughs of low pressure will attack the ridge of high pressure anchored over Russia, bringing cooler temperatures just 5°C (8°F) above average to Russia late next week. By ten days from now, the ECMWF model shows a strong trough of low pressure over Moscow, and a end to the Great Russian Heat Wave of 2010. Moscow still has to concern itself with smoke from the wildfires burning southeast of the city; winds are expected to shift early next week and bring the smoke towards the city again. However, the cooler weather should aid fire-fighting efforts, so the smoke problems should not be as bad as last week's nightmare.
Figure 2. Image from NASA's Aqua satellite of smoke from wildfires burning to the southeast of Moscow yesterday, August 12, 2010. Northerly winds were keeping the smoke from blowing over the city. Image credit: NASA.
The tropics are quiet
The remnants of Tropical Depression Five continue to bring heavy rain to portions of Southeast Louisiana today. Up to five inches of rain has fallen in regions near New Orleans. The GFS model predicts that the remains of TD 5 could move off the coast of Mississippi by the middle of next week and regenerate, but none of the other models is making this forecast. Both the GFS and ECMWF models are predicting that a tropical storm will develop off the coast of Africa by next Friday, August 20.
Donations urgently needed in Pakistan
The devastation wrought by the worst flooding in Pakistan's history requires a huge response by the international community. Wunderblogger Dr. Ricky Rood, author of our Climate Change Blog, has a friend working in Pakistan who underscored the desperate situation there:
This is the worst natural disaster in the history of Pakistan in terms of number of people and area affected. Although not as many people have been killed as in the 2005 earthquake, we have already nearly 900,000 displaced persons thus far just in Khyber Pakhtunkhwa. Crops are destroyed; shops, hotels, and other business have simply been swept away in Swat, which had just this year been cleared of Taliban and was on the way to recovery; and districts closer to Peshawar and parts of Peshawar district are still, or perhaps again after yesterday/today, under water. After the immediate emergency response, it will be years of rebuilding to replace what has been lost and to start to develop again. I know you have the power to control the weather, so if you cold give us a week or two without more rain at least we could keep the helicopters flying and give people a chance to go to their homes, recover what might still be there, set up tents if we can get enough to them, and start to clean up."
She gave the following recommendations for charities that do work in the flood-ravaged zone, and are effective at getting aid to those who need it the most:
Doctors Without Borders
The International Red Cross
MERLIN medical relief charity
The mobile giving service mGive allows one to text the word "SWAT" to 50555. The text will result in a $10 donation to the UN Refugee Agency (UNHCR) Pakistan Flood Relief Effort.
She mentioned that it is better to send money to the organizations doing the relief work than to try to organize shipments of goods.
Jeff Masters
Reader Comments
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ROFL
Nooo! Don't gooooo!
A TROUGH OF LOW PRESSURE...THE REMNANTS OF TD 5...WILL MOVE LITTLE
OVER THE WEEKEND. THE SOUTHEAST TO NORTHWEST ORIENTED TROUGH AXIS IS
FORECAST TO REMAIN EAST OF THE COASTAL WATERS...RESULTING IN A LIGHT
TO MODERATE WEST TO SOUTHWEST FLOW. WIND SPEEDS AROUND 15 KNOTS OR
LESS ARE EXPECTED OVER THE WEEKEND WITH SEAS OF UP TO 4 FEET...AS
WELL AS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
BY EARLY NEXT WEEK...AN AREA OF LOW PRESSURE WILL RE-DEVELOP NEAR
THE FLA PANHANDLE. THE LOW IS EXPECTED TO MOVE WEST ALONG THE COAST
AND COULD BRING AN INCREASE IN WINDS AND SEAS BY THE MIDDLE OF NEXT
WEEK. GFS AND ECMWF FOLLOW SIMILAR PATHS IN BRINGING THE SYSTEM
WEST...HOWEVER THE GFS APPEARS TO BE OVERDONE ON THE STRENGTH AT
THIS TIME SO LEANED TOWARD THE ECMWF SOLUTION FOR WINDS.
. .
0
No Active Tropical Warnings in the Atlantic, Caribbean, or Gulf of Mexico
By Maritime.CDO@navy.mil (NMFC CDO) from Naval Maritime Forecast Center Norfolk Virginia. Published on .
As of Fri 13 Aug 2010 22:01:02Z
2010 Storms
All Active Year
Atlantic
East Pacific
Central Pacific
West Pacific
Indian Ocean
Southern Hemisphere
Really adding em up isn't it?
that's beautiful! XD
A
Seeing as there isn't a C. 'Maybe', and the very strong model support for regeneration in the Gulf I'm going to grudgingly say 'Yes'
Probably a safer bet would be no. It could happen, but...from reading area discussions I would say the odds are 1 in 3 that it will.
Outlook
There is agreement among several extended range weather models of
taking a weak low pressure system over the deep south and looping
it back to the west later in the weekend.
The low is forecast to emerge back over the water...off the
Northwest Florida Coast...later in the day Sunday. Then moving
westward...skirting the Northern Gulf Coast Monday.
The weather will remain unsettled with the potential of numerous
showers/tstms...mainly closer to the main low pressure system with
scattered coverages on its periphery. At this time...the low is not
forecast to regenerate into a tropical system...but will be closely
monitored. stay tuned for later updates.
Seas are forecast to range between 3 and 5 feet. /10
Its over land, but close enough to where it can draw moisture from the GOMEX
Yup...a lot of flooding rains are possible. Be careful on the highways.
EXTENDED...FROM TUESDAY AND BEYOND TEMPERATURES LOOK MORE LIKELY
TO REMAIN BELOW 100 DEGREES AS BOTH THE 12Z GFS AND ECMWF
RE-INTENSIFY REMNANTS OF TROPICAL DEPRESSION NUMBER 5 BEGINNING
TUESDAY AFTERNOON. THE 00Z MODEL RUNS WERE WEAKER WITH THIS
FEATURE THOUGH...SO DID NOT WANT TO MAKE BIG CHANGES TO THE
FORECAST UNTIL THIS IS BETTER RESOLVED. BOTH THE GFS AND ECMWF
BRING A LOW PRESSURE SYSTEM OVER THE TX/LA GULF COAST DURING THE
PERIOD KEEPING NORTHEASTERLY LOW LVL FLOW THRU THE CWA WHICH
SHOULD KEEP THINGS RELATIVELY COOLER. THE GFS REMAINS MUCH
STRONGER WITH THIS LOW THAN THE ECMWF IS. HEAT INDICES WILL
LIKELY STILL BE AROUND 100 OR ABOVE...SO ITS NOT LIKELY TO BE A
HUGE RELIEF BUT AT LEAST LOOKS TO END THE STREAK OF 100 DEGREE
DAYS AND THE PERSISTENT HEAT ADVISORY.
Looking nice!
Interesting, we've a large ridge building in the PNW now.
So if we get a new low off the panhandle does it get TD6? I assume so since TD5 "dissipated"
Thanks for this video. I think some people don't realize the seriousness of a hurricane. Perhaps this will remove them from the cadre of wishcasters and put them in the category of serious weather-watchers.
You're probably right.
If this system comes off as high as the GFS indicates then it's unlikely that it will strengthen into a serious disturbance immediately upon arrival in the Atlantic. 17/18N is unusually high and it will have to deal with more stable air and lower SSTs than if it came off at the more convectional 10 - 15N. Take a page out of 93L's book. I'm almost certain that if it was about 5 degrees lower that it would have become a tropical cyclone.
"Brutal heatwaves, horrendous floods, enormous icebergs. Good thing global warming is a hoax, or this sure would be troubling." -- Mark Morford
National Hurricane Operations Plan
Excerpt:
3.3. Numbering of Tropical and Subtropical Cyclones.
Within a basin, if the remnant of a tropical cyclone redevelops into a tropical cyclone, it is assigned its original number or name. If the remnants of a former tropical cyclone regenerate in a new basin, the regenerated tropical cyclone will be given a new designation.
what does that image mean Storm? If you are gone already, can someone else explain? It doesn't have to be in depth. I see that the blue line is August and is more in the center of the quadrants, but that's about all i can gather from it.
You're probably right.
I would say it's naive to think we can't.
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