Call this one a “Humistorm” or “Torrid Tuesday.”
The “Extreme Heat Wave of 2011” set numerous all time heat index & humidity records in Minnesota Tuesday.
3 consecutive days with 80 degree dew points at MSP Airport. (First time that has ever happened according to UM climate guru Dr. Mark Seeley)
82 degree dew point new all time record high dew point at MSP Airport. (May have been as high as 84 degrees in between hours!)
119 degree heat index (3:53pm) at MSP Airport ties all time record heat index at MSP!
88 degree dew point at Moorhead last night between 6pm and 8pm sets new all time record highest dew point reading in Minnesota! (Previous record was 86 degrees)
134 degree heat index reading at Moorhead sets new all time highest heat index reading for Minnesota! (Previous record was 124 degrees at Moorhead in 1966)
A knowledgeable correspondent tells me:
I’m seeing dew point levels I’ve never (ever) seen before. MSP set a new record yesterday (82), but in-between hours the DP jumped to 84. We had 3 days/row with dew points at or above 80, which is unprecedented in the historical record going back to the mid-1800s. Moorhead saw an unimaginable dew point of 88 Tuesday around the dinner hour, heat index of 134 F. For a few hours Moorhead, Minnesota had the highest dew point (and highest heat index) of any regular reporting station on the planet. At Penn State I was taught that dew points in the upper 80s to near 90 were only possible along the shore of the Red Sea, in the Middle East.
Some are theorizing that evapotranspiration (sweaty corn) may be injecting more water into the air. Farmers can now cram more rows of corn into an acre. Other theories include more standing water (Missouri River flooding), even fracking for natural gas (which strains credulity a bit, but I guess nothing should be ruled out). For the past few days dew points over the Upper Midwest have consistently been 10 degrees higher than along the Gulf coast – the alleged source of most of our summer moisture.
Jeff Masters (Weather Underground) has called this heatwave a 1 in 7 year event, but he is apparently at a loss to explain the incredible levels of water vapor associated with this suffocating heat. No more gradual heatwaves either, the heat seems to come on suddenly, more like a heat “storm” than a heatwave.
One of my scientific advisors writes:
Some points. In summer there is a strong relationship between heat and moisture. Drought or dry areas lack evaporative cooling and provide a setting for heat waves to develop. Heat waves in turn dry out the soil.
Given the wet spring and extensive flooding over many regions, the evapotranspiration can be large and the high temperatures enable very high dew points that make conditions extremely uncomfortable. The human body keeps cool to a large extent by evaporation of moisture from the skin: sweat, and high dew points cut down on that cooling capacity.
We are now harvesting the environment left behind by the spring.
Meanwhile, the ever vigilant Rush Limbaugh reminds us – pay no attention to the heat index –
it’s a government plot.
Rush Limbaugh: They’re playing games with us on this heat wave, again. Even Drudge, drudge getting sucked in here. Gonna be a 116 in Washington. No, it’s not. It’s going to be a 100, maybe 99. The heat index, manufactured by the government, they tell you what it feels like when you add the humidity in there. 116 – When’s the last time the heat index was reported as an actual temperature? It hasn’t been. But it looks like they’re trying to get away with doing that now.
Dew points that high make me sweat just thinking about it.