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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Doesn't this whole setup over the NATL look weird to u guys?

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I read central florida hurricane sit a lot; it is quiet there unless something real is going on. Here people pull you in to arguments a lot. Next thing I know I start spewing nonsense too. This is better tonite, but erry just the same.
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Yeah, like the calm before the storm... with a vengeance...
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This is kinda erry in here tonight, think I'll go, just starting to feel like all hell might break loose in the tropics soon. Hummmmmmm
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Also, seb, I think we all got a little pie-eyed because we had a full-fledged hurricane before the end of June, and a pretty strong one at that, PLUS a second TD that nearly got to storm status a few days later. With that start, I think we all forgot that June storminess is no indicator of activity later in the season. I guess we set ourselves up in a way...
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I will read that and check your blog out, thank you.
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Quoting sebastianflorida:
I Think The Train Derailed!

Like many here, I have waited week after week for the season of doom to begin; only to be told wait one or two more weeks, well this waiting has gone on long enough, and that is good news to me.

However, I must lower my prediction, which was obviously a bit too high. Yes the factors for a busy season are there for the most, but a few factors for a season that is less terrible are also there, and those variables have one thus far.

I guess we will see 17 named storms, leaving 14 more to come; with 8 becomming hurricanes, and 3 becomming majors. This leaves us with a season total of 17/9/3. I do think we will have a very busy period from August 21 to Nov 10th, which will be the main part of the season.

I remember finding in a reputable article a couple of months ago (can't remember the source) that La Nina years like current can start late. That might explain a lot about the 2010 season to date.

This entry is just me sorting out the season in my mind, so please don't get on my case about downcasting etc, I am just sharing some thoughts and opinions here today.

Thanks
Hey, seb. Did u read Klotzbach's commentary on the alleged slow start to the season? He makes some salient points about the correlations between La Nina conditions similar to those we have right now and the time of the second hurricane of the season.

I appended some information to the dataset he used and came up with some interesting conclusions about the season's potential based on climatology, including a 67% likelihood that there would be at least one storm after Nov 1. I have posted my thinking in my blog if u are interested in reading that.
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I think everyone poofed everyone else, and no one is left but me and a few others.
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2413. xcool





Member Since: September 26, 2009 Posts: 2 Comments: 15603
Many a pretty storm crossing Africa comes off the coast into the Atlantic, to almost immediately fall apart from the shock of hitting the ocean environment.
So why should exTD5 reorganize itself upon reentering the Gulf?

The above is an actual question from a weather naif seeking an explanation...
...and not a rhetorical argument that a TropicalCyclone won't reform outta exTD5.
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2409. xcool
AL, 05, 2010081500, , BEST, 0, 329N, 854W, 20, 1012, LO
Member Since: September 26, 2009 Posts: 2 Comments: 15603
"Photobucket"

Seem like the 18z ensembles have a wide rage of solutions for us.
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Quoting jasoncoolman2010xx:
we will never know if the storm will hit east coast its little to far out..


We will know in a couple of weeks....
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Just checked in again and am digging that (0) activity in the Atlantic !!! Oh Yes, I LIKE IT !!!!
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I Think The Train Derailed!

Like many here, I have waited week after week for the season of doom to begin; only to be told wait one or two more weeks, well this waiting has gone on long enough, and that is good news to me.

However, I must lower my prediction, which was obviously a bit too high. Yes the factors for a busy season are there for the most, but a few factors for a season that is less terrible are also there, and those variables have one thus far.

I guess we will see 17 named storms, leaving 14 more to come; with 8 becomming hurricanes, and 3 becomming majors. This leaves us with a season total of 17/9/3. I do think we will have a very busy period from August 21 to Nov 10th, which will be the main part of the season.

I remember finding in a reputable article a couple of months ago (can't remember the source) that La Nina years like current can start late. That might explain a lot about the 2010 season to date.

This entry is just me sorting out the season in my mind, so please don't get on my case about downcasting etc, I am just sharing some thoughts and opinions here today.

Thanks
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Just studied the steering currents that are forecast out to 72 hours. By the looks of things, ex-TD5 should begin emerging out over the Gulf by 00z Monday (this time tomorrow) and should be south of Pensacola by Monday evening. By Tuesday afternoon, steering currents should become weaker and slow the pace of the system. Late Tuesday night into early Wednesday, the system should be making landfall around the mouth of the Mississippi River in Louisiana. Looking at the shear forecast, upper level conditions should be favorable to very favorable for tropical development. Going by the current steering forecast, I have to believe it will emerge over water. Just how far it emerges over water will determine the strength. If the center is able to move 50 miles or more off the coast, I like the chances of it becoming a minimal to moderate strength tropical storm. All of this is subject to change if the steering currents change between now and then.
Member Since: July 15, 2006 Posts: 17 Comments: 10156
Link Im learning.
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2395. KEEPEROFTHEGATE (Mod)
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2391. KEEPEROFTHEGATE (Mod)
and there is nothing wrong with that
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Quoting katrinakat5:
lol it's the tropics the middle part of august and nothing to talk about except a rain maker...this season still has a shot if the ulls dont keep popping up everytime something tries to form...not good..

actually it is very good.. that means no hits towards US.. JMO
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2388. palmpt
Quoting xcool:



moveing south ...


Right on schedule.
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Anyone have any input on Septembers possible storm tracks?? more recurving storms? or perhaps landfalling? Thanks
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2384. KEEPEROFTHEGATE (Mod)
2378. tkeith
This comment has been removed for violating the Community Standards.
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2383. KEEPEROFTHEGATE (Mod)
Quoting HurricaneDanielle:


those ridges need to go westward, significantly so, or else we're gonna have a lot of fish storms, ---____----
well fish storms it will be then as you say so it will be
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2375. KEEPEROFTHEGATE (Mod)
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About JeffMasters

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