Huge metro Urban Heat Island; Rain on the way; Olympic washout?

73 degrees at MSP Airport at 6am today

57 degrees in Lakeville at 6am

16 degrees Huttner Weather Lab “UHI Index” today

Scattered showers & T-Storms creeping back into the forecast

Slight risk from SPC for isolated severe storms Friday

84 degrees warmest average metro high of the year (through July 22nd)

65 degrees warmest average metro low of the year this weekend

“Flood-O-lympics?” Wettest summer on record has Britain concerned about dismal Olympic weather

Quick look MSP Forecast:

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Source: Twin Cities NWS

Major Metro Urban Heat island effect today:

They say “all weather is local.”

That was certainly true this morning around the Twin Cities metro.

I witnessed one of the biggest Urban Heat Island effects today I have ever seen in 40+ years of watching and forecasting weather in the Twin Cities.

Check out these observed temperatures at 6am around the metro.

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Source: Twin Cities NWS

That’s a 16 degree temperature difference between Lakeville and MSP Airport this morning! The “UHI Index” of 16 is the highest I can remember seeing around the metro in a very long time. (Yes, I made the term “UHI Index” up, I’m using the difference between the warmest inner city temp and surrounding “outlying” suburban temp around the metro.)

The map below clearly shows how the urban environment holds heat in on a calm night.



The temperature difference of 16 degrees this morning was literally the difference between running your AC all night to sleep well in the city, and windows wide open “good sleeping weather” in the outer suburbs.

Many UHI studies have been done over the years. Dr. Andrew Comrie from the University of Arizona has done good work on UHI around Tucson, and I’ve interviewed him many times. Here’s an excerpt from one of his studies on UHI.

An analysis of 30-yr temporal trends in urban and nonurban minimum temperatures across the region shows the rate of urban warming to be about three-quarters of the general regional warming. Tucson’s urban heat island is ∼3°C over the last century, with >2°C of this warming in the last 30 years. The annual average urban warming trend over the last three decades is 0.071°C yr-1 with the strongest effect in March and the weakest effect in November.

Rain on the Way:

A relatively weak low pressure system is gliding slowly into Minnesota from the Dakotas today. Look for scattered showers and a few T-Storms to gradually increase in coverage from west to east.

Western Minnesota will be the focus for rain today, and rain chances will increase in eastern Minnesota tonight. Overnight and Friday looks like the best bet for picking up some much needed rainfall in the metro.

The system is not well organized, but there is a slight risk that a few borderline severe storms could pop up in western Minnesota today and shift east Friday.

SPC has a slight risk including the metro Friday.

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Source: NOAA/SPC

Peak of summer next 2 weeks!

The next two weeks are the “warmest” climatologically speaking in Minnesota.

The average high in the Twin Cities is now 84 degrees through July 22nd. That’s the warmest average high of the year at MSP. The average low this weekend is 65 degrees…also the warmest of the year!

“Water-Lympics 2012?”

Meterologist are working overtime these days trying to get a handle on the forecast for the upcoming 2012 Summer Olymics in London.

This has been the wettest summer on record for much of Great Britain, and the short term forecasts call for more of the same.

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Source: BBC

UK Warnings

Weather Warning

Thursday 12th July


Outbreaks of heavy rain are expected to reach southwest England during Thursday morning and extend east across the rest of southern England on Thursday afternoon.

Saturated ground means that there is a continuing risk of flooding.

The dismal forecast even has Brits looking for ways to make it stop raining.

Brits are used to dismal weather, but this summer has them preparing for the worst for the Games. The Spec has the story.

LONDON Less than three weeks before the start of the 2012 Olympics, British officials and athletes around the globe are bracing for a dark threat to the London Games: English weather.

In a city universally besmirched as climatically challenged — and about which Jane Austen once wrote, “in London, it is always a sickly season,” — early Olympic forecasts are cloudy with a chance of chaos. As Britain copes with what is so far the wettest summer since records began in 1910, meteorological “war rooms” are being set up at the Olympic Park in East London as well as other British host cities including Eton and Weymouth.

Suggesting scenes of mud-caked Olympians ahead, torrential downpours have already wreaked havoc at recent British sporting events, including massive disruptions that turned at least 10,000 spectators away from the Formula One race at Silverstone last week.

In June, areas across the nation saw double the average rainfall, with July also bringing flash floods that continue to turn roads into rivers and inundate homes and businesses in parts of the country. Extended forecasts suggest that while the bouts of heavy rain may abate, London weather could still be wetter than the already-moist average for much of the 2012 Games — testing years-in-the-making transit planning and potentially affecting the medal count.

Could the dreadful weather even creep into the “tone” of broadcasters covering the Games? One study from thinks so.

Using coverage of the 2008 Summer Olympics in Beijing as a basis, the researchers examined how air pollution and weather — by producing cloudy conditions as opposed to sunlight — might have impacted coverage of those Games. They examined four major U.S. newspapers and found that as air pollution increased and temperatures rose, journalists were more likely to use negative words in stories about the host country and about competitors from China and the United States when reporting.

Because London is known for its cloudiness and rain, researchers think the tone of coverage of the 2012 Olympic Games in London could be impacted if grey and misty conditions exit. If so, reporters might focus more on what is wrong with the Games. But if the weather is ideal, reporters are more likely to give the Olympics a higher grade, if the research from Beijing holds true.

The study — authored by Bu Zhong, associate professor in the College of Communications, and published in a special Olympic issue of Mass Communication and Society — suggests there is a relationship between weather and journalism coverage, and notes that negative and positive language in news reports can be further impacted by factors such as deadline pressure, living in an unknown country and personal feelings about a sporting event.

By discovering a potential link between the environment and media coverage, the researchers caution journalists to be aware of any potential subconscious bias they are including in their reports — whether they are covering the Olympics or some other event where weather can be a factor.

“This article suggests that journalists’ decision making could be influenced by a greater variety of factors than we previously thought,” said Zhong, a senior research fellow in the John Curley Center for Sports Journalism at Penn State. “To better understand journalists’ thinking process, it is necessary to explore not only known patterns of journalistic practices, but also some exogenous factors, such as weather.”

There is still hope for some improvement in the forecast by the time the games begin. But it looks like the weather may be a tough competitor in the 2012 London Summer Games.


  • Sunny Acres

    Having lived near Prescott for the last twenty years, I’ve noticed the heat island effect especially with regard to rain events. When a cold front arrives from the west, the heat of the heat island can cause the storm to dissipate as it moves across the metro area to the east. The heat island seems to flow to the southeast, passing into Wisconsin. The storms often then reinvigorate or reform halfway through Pierce county. The heat island also sometimes seems to have the effect of bifurcating a storm so that some flows southeast while the other half flows to the east, with the cutoff being around the confluence of the Mississippi and the St. Croix River.

    Of course, these are just uneducated observations, for what they’re worth.

  • bobbydole

    I often wonder how much cooler the official high would be if it was located away from the airport. Some days significant difference between the high at my house, and the high at the airport, even though I’m only 5 or so miles west.