Causes of the Russian heat wave and Pakistani floods

By: Dr. Jeff Masters , 2:56 PM GMT on August 13, 2010

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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

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1723. Patrap
Member Since: July 3, 2005 Posts: 420 Comments: 127543
1722. tkeith
Quoting CybrTeddy:


True, but most major hurricanes develop off Africa, average season sees two major hurricanes.
It does have climatology on it's side.
Member Since: November 1, 2004 Posts: 25 Comments: 8923
#1714 reported.
Member Since: Posts: Comments:
1720. Drakoen
Satellite images and surface observations support a broad area of low pressure over Alabama. Looks like the mid level circulation is pushing to the southeast getting ready to make that loop that is the consensus among the computer forecast models.

Member Since: October 28, 2006 Posts: 57 Comments: 29886
Quoting msphar:
Not every wave from Africa is productive. In fact some knowledgeable wave trackers say that only 10% to 15% are able to develop into tropical cyclones. Getting that percentage correct is important in determining the total impact of any CV season.


True, but most major hurricanes develop off Africa, average season sees two major hurricanes.
Member Since: July 8, 2005 Posts: 259 Comments: 23565
1717. tkeith
Quoting CybrTeddy:


heh. NAO? MJO? GFS? CFS? CMC?
you're gettin warmer...
Member Since: November 1, 2004 Posts: 25 Comments: 8923
PGI30L will be emerging at a latitude south enough that SAL will only be having a minimal affect on it, even as it works its vigorous mid-level circulation down to the suface. And to add on top of that, PGI28L will be aiding to clear the SAL out along with all the moisture currently in front of PGI30L. Don't you think that the global models incorporate SAL into their forecasts? I mean, the ECMWF, GFS, CMC, and NOGAPS all develop this into a tropical cyclone. PGI30L should be emerging at about 12N in 72 hours.

Look at all the moisture in front of PGI30L, that will help undoubtedly to clear the SAL.

Member Since: Posts: Comments:
Quoting Patrap:
can you spell out the word, '' irrelevancy''?

Easily..

in 3 Letters.

..and it aint "SAL".



heh. NAO? MJO? GFS? CFS? CMC?
Member Since: July 8, 2005 Posts: 259 Comments: 23565
1712. IKE
1707....yeah...if I don't post it, no one will see it and it won't happen.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
1711. msphar
Not every wave from Africa is productive. In fact some knowledgeable wave trackers say that only 10% to 15% are able to develop into tropical cyclones. Getting that percentage correct is important in determining the total impact of any CV season.
Member Since: Posts: Comments:
1710. Drakoen
Quoting JRRP:
jump to north



Back and forth
Member Since: October 28, 2006 Posts: 57 Comments: 29886
1709. tkeith
Quoting IKE:


You're correct.
right on cue...
Member Since: November 1, 2004 Posts: 25 Comments: 8923
1708. IKE
Quoting JRRP:
jump to north



You're correct.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting LoneStarWeather:

Whatever. I'll believe it when I see it. You keep believing in your models.


Well, sorry to break it to you but the last two systems I have seen with such tight model support coming off Africa was Bertha and Dean. Just sayin. The models are usually pretty spot on when multiple models pick up and keep up on the same system. Besides, we're in that time of season where things develop. Shall I bring out the chart again?
Member Since: July 8, 2005 Posts: 259 Comments: 23565
Seriously thwarting our plans to finish organizing the relief TrailerLink
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1704. JRRP
jump to north

Member Since: Posts: Comments:
Quoting HurricaneSwirl:


Change the address in the address bar. For example

"http://www.aoml.noaa.gov/phod/dataphod1/work/HHP/NEW/2010220at.jpg"

That is for August, 8, 2010. Change the 2010 to 2005 and it is now addressed to August, 8, 2005. To go to a different date change the number after 2010. "220" is August 8. "221" is August 9.
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1702. JRRP
Member Since: Posts: Comments:
1698. tkeith
Quoting Patrap:
can you spell out the word, '' irrelevancy''?

Easily..

in 3 Letters.and it aint SAL.

LMAO...
Member Since: November 1, 2004 Posts: 25 Comments: 8923
1696. JRRP

SAL forecast
Member Since: Posts: Comments:
1694. Patrap
3 days ago..



Current

Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting CybrTeddy:


They have not, this is the first time all season that the models are so tight and constant on developing a system.

Whatever. I'll believe it when I see it. You keep believing in your models.
Member Since: Posts: Comments:
Quoting IKE:
SAL has made a comeback...



Coming to a "theater" near you.. LOL.
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1691. Patrap
SAL is a on the increase and IS affecting any development now.

Atlantic SAL 5-Day loop


Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting SeniorPoppy:


That SAL will kill whatever is trying to form if it continues to build. Not to mention the tropical Atlantic is pretty darn dry even without new SAL outbreaks. This will probably break down pretty soon, but I do not this will be the case next week. :) JMO


The system's beginning latitude in the models is below most of the SAL. And as Teddy said, the first wave will help somewhat.
Member Since: Posts: Comments:
Quoting CybrTeddy:


They have not, this is the first time all season that the models are so tight and constant on developing a system.


This is true.
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1688. IKE
SAL has made a comeback...

Member Since: June 9, 2005 Posts: 23 Comments: 37858
1687. Patrap
Member Since: July 3, 2005 Posts: 420 Comments: 127543
Quoting LoneStarWeather:

Seems like they've been developing something "next week" for a few weeks now...


Um, no they haven't, not like this at any point in time this season.
Member Since: Posts: Comments:
Quoting LoneStarWeather:

Seems like they've been developing something "next week" for a few weeks now...


They have not, this is the first time all season that the models are so tight and constant on developing a system.
Member Since: July 8, 2005 Posts: 259 Comments: 23565
1684. unf97
Quoting charlestonscnanny:

I see someone did post about it, thanks


Yeah, I mentioned the Mesoscale Convective Complex a short time ago. I expect this to fade later today, but the MCC is sliding S-SW parallel the SC coastline.
Member Since: September 25, 2007 Posts: 0 Comments: 1193
Quoting CybrTeddy:


Almost all models develop a CV system next week, and a potent one too. They also all regenerate TD5.

Seems like they've been developing something "next week" for a few weeks now...
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1682. tkeith
Quoting stormwatcherCI:
I did not see him reply so just FYI he is on Grand Cayman.
I thought so, thanks.
Member Since: November 1, 2004 Posts: 25 Comments: 8923
Quoting CybrTeddy:


Almost all models develop a CV system next week, and a potent one too. They also all regenerate TD5.


That SAL will kill whatever is trying to form if it continues to build. Not to mention the tropical Atlantic is pretty darn dry even without new SAL outbreaks. This will probably break down pretty soon, but I do not this will be the case next week. :) JMO
Member Since: Posts: Comments:
1678. Patrap
1673.

Its called east coast wish-itis,

LOL
Member Since: July 3, 2005 Posts: 420 Comments: 127543
1676. DDR
Tropical wave/ITCZ moving in again
Link
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PGI28L will sacrifice itself to the dust storm to allow PGI30L to develop.
Member Since: July 8, 2005 Posts: 259 Comments: 23565

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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.

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