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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so far belizeit the nam model is holding true with our caribean system
Member Since: June 13, 2009 Posts: 2 Comments: 12719
Quoting CarnageCaster:


That factor becomes non-existent during the peak of the season.


It doesn't become non-existent, it just becomes less of a factor.
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Quoting redwagon:
And for those who don't think it's possible for TD5 to do what the CMC and GFS suggest, remember prairiecane Erin a couple years back who completely flooded the upper midwest on a 1000 mile run before she finally fell apart.


And intensified way over land - was amazing to watch.
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Quoting wunderkidcayman:
TropicalAnalystwx13 I got a strong feeling that earl will be further south like near 10N 25W instead of 16/17N 25W


I reckon that our next named storm will be from the system you referred to as Earl. While the possibility of ex TD5 recurving is there, it's more of a slim chance and i think it's unlikely that we would see Danielle from it.
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Quoting CarnageCaster:


That factor becomes non-existent during the peak of the season.


That's false.
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12z GFS weakens "Earl" a tad bit and starts recurving it (slightly) near 40W.

216 hours:

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Quoting NHCstevehayward:
Good afternoon !!


Hi!
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Strengthened just a tad, or held intensity:



Holding Intensity:



Weakening:



Holding Intensity, or weakening slightly:



Holding or strengthening slightly:



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Quoting TropicalAnalystwx13:


Ughhh....Are you real or an imposter?


A JFV wanna be. what a joke.
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And for those who don't think it's possible for TD5 to do what the CMC and GFS suggest, remember prairiecane Erin a couple years back who completely flooded the upper midwest on a 1000 mile run before she finally fell apart.
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TropicalAnalystwx13 I got a strong feeling that earl will be further south like near 10N 25W instead of 16/17N 25W
Member Since: June 13, 2009 Posts: 2 Comments: 12719
Quoting calder:


Oh dear, seems we're back into the swing of naming storms a week before they are even invests...


Well.. its TD5 the models are showing. Its too early to call a certain storm 'Danielle' or 'Earl' though, looses a ounce of credibility if they don't.
Member Since: July 8, 2005 Posts: 259 Comments: 24579
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Holding Intensity:

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Looks like the CFS really backed off the upward motion phase for later this month.

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Quoting Stormchaser2007:
12z

About the 8th run that the GFS develops the tropical wave currently over central Africa.
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Quoting MiamiHurricanes09:
It's a global model...998mb probably means minimal hurricane.


Mb predictions aside, the density of closed isobars would indicate a rather healthy system.
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Quoting CybrTeddy:


Post 122.


Oh dear, seems we're back into the swing of naming storms a week before they are even invests...
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12z

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Although the thought of a low moving inland and then doing a 180 and popping right back out again is kind of unusual, even to the point of not being believable, who says it can't happen?

If you like at this "system low" now and over the past few days you will notice, or at least I do, that it pushed in in the lower MS region and is now moving in a direction over north Mobile which means that it has to have turned in a direction that is close enough to 180 to at least make the scenario believable.

As for discounting people for getting forecasts wrong I would say the following:-

1. Most here get em wrong, that's the nature of the beast.

2. Blog = opinion, you're supposed to be invited to give an opinion, not villified for doing so.

3. Don't care if you agree or not quite frankly, the blogger is not being rewarded based on your assessment of their abilities.

4. For God's sake live and let live. Who gives a flying fig, just participate and enjoy!
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Quoting TropicalAnalystwx13:
Landfall:

What factors is this scenario based on? Trying to get caught up and just realized it was over Texas. :)
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Quoting calder:


Where's Danielle?!


Post 122.
Member Since: July 8, 2005 Posts: 259 Comments: 24579
Not even noon yet and it's 97 degrees! Calling for a high of 107 today here in Oklahoma! This is utterly ridiculous. Hopefully the relief is coming soon.
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Quoting CybrTeddy:


Probably a TS, but a pretty darn healthy one. Lets see if models begin to strengthen this too.
It's a global model...998mb probably means minimal hurricane.
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Quoting TropicalAnalystwx13:
Here's Earl:



Where's Danielle?!
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Quoting DestinJeff:
TD5 demanding some respect.


All it needed was a little bit of land?


lol, crazy tropics.
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Quoting TropicalAnalystwx13:
Second Hurricane of the season...I think. 999 mb...Strong TS or Weak Hurricane?



Probably a TS, but a pretty darn healthy one. Lets see if models begin to strengthen this too.
Member Since: July 8, 2005 Posts: 259 Comments: 24579
Quoting DestinJeff:
TD5 demanding some respect.


lol
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Second Hurricane of the season...I think. 999 mb...Strong TS or Weak Hurricane?

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Quoting TropicalAnalystwx13:
Landfall:

That would be the worst case scenario as Bastardi said.
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131. IKE
Quoting CarnageCaster:
Hi, Ike. What's new?


Staying dry inside.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
130. IKE
TD5 may be a problem all week if the GFS verifies.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Here's Earl:

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Quoting extreme236:
Ex-TD5 seems to cling very near the coast, but does strengthen fairly impressively on the GFS. Probably thinks to very warm coastal waters and friction with land.


Agreed.
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Quoting extreme236:
Ex-TD5 seems to cling very near the coast, but does strengthen fairly impressively on the GFS. Probably thinks to very warm coastal waters and friction with land.


Same reason why see storms always ramp up when they reach the coast under favorable conditions. A system clinging to the coast line for days under 31C waters and with low shear like the GFS is indicating is bound to cause trouble.
Member Since: July 8, 2005 Posts: 259 Comments: 24579
Landfall:

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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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