Late June/Early July Extreme Heat Episode

[nwohweather]

Hard to know what dewpoints were like but I think part of the reason for the warmer overnight lows back then is simply due to site location. A lot of the official obs in 1936 were in/near the downtowns of cities. Nowadays a lot of the official obs come from the fringes of a city.

Even if it were on the outskirts of the city the high soil temperatures would have kept the temps up

[tornadotony]

Even if it were on the outskirts of the city the high soil temperatures would have kept the temps up

Not as drastically as you would think. Asphalt and concrete are far far superior for radiating heat than soil. Below is a chart of albedos for certain substances. Note that the less that is reflected (aka the lower the albedo), the more energy is absorbed in the substance and available for reradiation into the atmosphere. This is generally speaking, of course. There are other properties of substances that affect the rate of radiation and such. Asphalt and soil (especially dry soil) both reradiate fairly efficiently, but asphalt has more energy available to reradiate.

Chart source: http://ecosystems.wc...gumentsfor.html

[BeauDodson]

Posted a ton of maps concerning June

http://weatherobservatory.blogspot.com/2012/07/july-9th-13th-not-as-hot-some-rain.html

Historic month for many areas - hot and dry. We have picked up a little bit of rain over the last few days in our region - nothing to break the drought. We will take what we can get. Hoping the front shifts a bit further north over the coming days.

[cyclone77]

Looks like the Euro is holding off on the real heat until late in the weekend/early next week now. Looks like it gets cut off later in the week from the north again, so this may be a brief, more moderate shot of heat. If we get another major heat wave it probably won't be until late July or early August IMO.

[Chicago WX]

14 consecutive days and counting of days with 90º+ at IND. Longest such streaks for Indianapolis below...

23 days: July 17-August 8, 2012

19 days: August 8-26, 1936

18 days: July 13-30, 1901

15 days: July 3-17, 1936

14 days: June 27-July 10, 2012

14 days: July 31-August 13, 2007

14 days: July 11-24, 1983

14 days: July 7-20, 1980

14 days: June 23-July 6, 1966

13 days: August 18-30, 1983

13 days: July 19-31, 1940

Looks like the streak may meet its demise by Friday and/or the weekend...if the rainfall materializes. We'll see.

[Chicago WX]

And Fort Wayne will break their record (14 in July 1983 and the current one) of consecutive 90º+ days today, outside of something flukey happening.

http://www.crh.noaa....?n=iwxheatstats

[IWXwx]

And Fort Wayne will break their record (14 in July 1983 and the current one) of consecutive 90º+ days today, outside of something flukey happening.

http://www.crh.noaa....?n=iwxheatstats

It may be close. Their point-n-click is 90 and it's 84 at noon. Normally, all of those 90's in a row would seem like a big deal, but with those 100+'s thrown into the middle of the streak, 90 doesn't seem unbearable.

EDIT: It made it, barely. High of 90 as of 4PM.

RECORD EVENT REPORT

NATIONAL WEATHER SERVICE NORTHERN INDIANA

0311 PM EDT WED JUL 11 2012

...RECORD NUMBER OF CONSECUTIVE 90 DEGREE DAYS SET AT FORT WAYNE...

WITH A HIGH TEMPERATURE OF 90 DEGREES THUS FAR...THE RECORD NUMBER

OF DAYS WITH A MAXIMUM TEMPERATURE OF 90 DEGREES OR GREATER WAS SET

TODAY AT FORT WAYNE. TODAY WAS THE 15TH CONSECUTIVE DAY OF AT LEAST

90 DEGREE TEMPERATURES.

THE PREVIOUS RECORD WAS 14 CONSECUTIVE 90+ DEGREE DAYS DURING THE

PERIOD ENDING JULY 23...1983.

[Hoosier]

There have been 22 heat related deaths confirmed so far in Chicago/Cook County. Huge progress has been made since the 1995 disaster and even 1999 which killed about 100 I think.

http://www.suntimes.com/news/metro/13723173-418/three-more-heat-related-deaths-bring-total-to-22.html

[KokomoWX]

There have been 22 heat related deaths confirmed so far in Chicago/Cook County. Huge progress has been made since the 1995 disaster and even 1999 which killed about 100 I think.

http://www.suntimes....otal-to-22.html

I think they just use guns for killing now.

[michsnowfreak]

Not as drastically as you would think. Asphalt and concrete are far far superior for radiating heat than soil. Below is a chart of albedos for certain substances. Note that the less that is reflected (aka the lower the albedo), the more energy is absorbed in the substance and available for reradiation into the atmosphere. This is generally speaking, of course. There are other properties of substances that affect the rate of radiation and such. Asphalt and soil (especially dry soil) both reradiate fairly efficiently, but asphalt has more energy available to reradiate.

Chart source: http://ecosystems.wc...gumentsfor.html

Very good points and awesome chart. Although I just cringe in general when I hear about low temps, especially during extremes. Especially the whole "record highs outnumber record lows 2-1 since 2000". For the past year we have been in a pattern dominated by above-normal warmth with just transient cold shots (and thus record highs outpacing record lows on a much greater scale). There is no way around that. But in general, the whole low temperature thing is so tainted by UHI. Concrete jungles are huge radiators of heat, so thats no surprise, and yes during the 1936 heatwave temps here were taken right in Detroit (unlike present-day suburban DTW). For instance if the same conditions, dews, etc of that 1936 heatwave had been repeated with this 2012 heatwave at DTW, I suspect lows would look fairly similar. (Taking nothing away from this 2012 heatwave, it wasnt even on the same planet as 1936 here...its like comparing GHD blizzard to April 1886 here). I wish there was some way to notate conditions (concrete, UHI) for the official weather record. Because the radiational cooling that affected the official Detroit site from 1966 (when it moved from urban DET to then-rural DTW) to approx the mid-late 1980s was profoundly different than pre-1966 (urban DET) or post-1990 (huge increase in UHI). All you have to do is compare lows temps at area sites whose urban/rural condition has not changed overtime to note the difference. So its almost unfair how much of an advantage cold weather records had during that 20-25 year stretch from the '60s to the '80s (esp since there were many years when cold already dominated anyway). Sorry if I strayed too much OT in getting my point across lol.