Causes of the Russian heat wave and Pakistani floods

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

Share this Blog
4
+

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

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 2025 - 1975

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 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66Blog Index

2025. scott39
Quoting TexasHurricane:
XTD5 wants a name this time. Will see
Member Since: Posts: Comments:
2024. pottery
It has stopped raining, for the moment here.
But the sky is Heavy with more to come shortly it seems.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting palmpt:


Including bastardi!


True!
Member Since: Posts: Comments:
2019. scott39
Quoting StSimonsIslandGAGuy:



Yes, he does.
:O
Member Since: Posts: Comments:
Most if not all global models suggest that at least 2 tropical cyclones develop in the next 7 days. Guess that "lid" is about to come off.
Member Since: Posts: Comments:
2014. palmpt
Quoting StormW:


Oh. I've noticed some of these agencies have been pretty slow at updating things.


Including bastardi!
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Hey, this is 200+ hours out, likely to be wrong. We'll have to see what it does if and when it turns into a tropical cyclone, at this point it would do a Dean, a Floyd, or a Bill.


If it's a Floyd, Conway, SC is doomed again.
Member Since: Posts: Comments:
2005. scott39
Quoting HurricaneDanielle:
Strom, is this ''fish'' trend going to continue into September? Gosh, I HOPE NOT, :(.
So you hope Major Hurricanes hit land?
Member Since: Posts: Comments:
Quoting Twinkster:


Miami I saw earlier that you said that this would recurve because of it being at 20N before 60W. Normally I would agree with you, but because of the ECMWF's predictions of a negative NAO around that time period, the trough that is causing the weakness could lift out fairly quickly and give the high ample time to build back in and push the system back to the w-wnw. IMO the east coast needs to watch this
True. Still too far out to know for sure, but should be watched for trends.
Member Since: Posts: Comments:
Storm, I can't remember if I asked this before or not. If I did then I apologize. The way things are shaping up should we see storms go more north (fish storms) and then later on go more west or will it just vary from storm to storm? I was thinking they were suppose to go more west this year....
Member Since: Posts: Comments:
.
Member Since: Posts: Comments:
Quoting StormW:


That' what I said...he asked if the wave that the models are developing would be affected by the SAL...my response was, regarding which one would be affected by SAL, If it's PGl-30L, no. The one west of it, yes.
Oh, I thought he was talking about which one the global models developed. Sorry!
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Other way around, PGI30L is the one turned into a tropical cyclone by the global models. PGI28L is supposed to head out to sea, but the ECMWF turned it into a TD in the 12z run.


Miami I saw earlier that you said that this would recurve because of it being at 20N before 60W. Normally I would agree with you, but because of the ECMWF's predictions of a negative NAO around that time period, the trough that is causing the weakness could lift out fairly quickly and give the high ample time to build back in and push the system back to the w-wnw. IMO the east coast needs to watch this
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Other way around, PGI30L is the one turned into a tropical cyclone by the global models. PGI28L is supposed to head out to sea, but the ECMWF turned it into a TD in the 12z run.


No he was answering my question earlier as to whether he think PGI30L would be affected by SAL or not
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
ECMWF 12z 240 hours, PGI28L as a TD in the Caribbean with a hurricane out of PGI30L.



Well it is hard to assume if that is a TD or not, but yes looks as though 30L is a hurricane.
Member Since: Posts: Comments:
Quoting StormW:


If it's PGl-30L, no. The one west of it, yes.
Other way around, PGI30L is the one turned into a tropical cyclone by the global models. PGI28L is supposed to head out to sea, but the ECMWF turned it into a TD in the 12z run.
Member Since: Posts: Comments:
Quoting StSimonsIslandGAGuy:
I think hurricane Danielle will last a lot longer than the handle in here at the rate the comments are being yanked ;)

Agree!
Member Since: Posts: Comments:
ECMWF 12z 240 hours, PGI28L as a TD in the Caribbean with a hurricane out of PGI30L.

Member Since: Posts: Comments:
Quoting IKE:
Have a good afternoon everybody.
You too IKE!
Member Since: Posts: Comments:
Quoting StormW:
Looks like we could be getting some spin in the ITCZ nea 7N;37W:

RGB LOOP


Could that be Storm PGI27L that UW-CIMSS tracks today?
Member Since: Posts: Comments:
1976. IKE
Have a good afternoon everybody.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
just curious why so many here are so worried about something 4500 miles away? Where all the models right now point to something in the near term affecting the conus with at least flooding rains or worse.You know just because it does not show it affect the east coast of florida does not mean the rest of the world can be affected.At least let it devlop and get to 40 west before people in the us conus have a heart attck>why not unplug the computer and go out enjoy life God does not promise us a tomorrow.And i guarantee you in the next 7 days no one in east florida will have any affects from this wave. On the other hand the folks on the north gulf coast are assured of at least some more bad weather how bad is still up up in the air.I guarantee you though its not 4500 miles away .
Member Since: Posts: Comments:

Viewing: 2025 - 1975

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 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66Blog Index

Top of Page

About

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