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Knightking2018

Highest heat index by state

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  What are the hottest heat indexes by each state? You won't believe that #1 is in Wisconsin. Appleton, Wisconsin July 13, 1995. The temperature was 101F, the RH was 71%, the dewpoint was 90F and the heat index was an astonishing 149F. 

  

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Since it partly depends on dewpoints, I feel like this one might be even more prone to error/uncertainty than the coldest wind chills.  I recall seeing a number of suspicious dewpoint readings (too low or too high) over the years, although getting inflated numbers near/over cornfields is a real thing. 

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On 5/31/2018 at 12:45 AM, Knightking2018 said:

  What are the hottest heat indexes by each state? You won't believe that #1 is in Wisconsin. Appleton, Wisconsin July 13, 1995. The temperature was 101F, the RH was 71%, the dewpoint was 90F and the heat index was an astonishing 149F. 

  

I cant even fathom a dewpoint of 90. The highest I ever felt was 82 and that was beyond miserable. 

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11 minutes ago, josh_4184 said:

I cant even fathom a dewpoint of 90. The highest I ever felt was 82 and that was beyond miserable. 

How much rain did Appleton receive shortly before that day to get a dew of 90F?  To me that is suspect but if true would be close to incredible, especially for its location.

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19 hours ago, wisconsinwx said:

How much rain did Appleton receive shortly before that day to get a dew of 90F?  To me that is suspect but if true would be close to incredible, especially for its location.

   I don't see anything in regards to precipitation for that date but wunderground has it as a temp of 101F with relative humidity of 71%. The day before that it was cooler and pretty muggy. Yesterday in my area I had a temp of 103F relative humidity of 45% creating a heat index around 120F. The dewpoint was around 80F. It was baking outside. 

  Here is more information on that heat index from Appleton. It is either 148F or 149F if rounded to the highest degree. https://site.extension.uga.edu/climate/2015/07/scorching-heat-in-iran-and-elsewhere/

 

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Based on the article below from the IL State Climatologist, 121F is a very conservative starting point for the Illinois heat index record (Peoria on 7/13/1995). However, I would actually go with 125F at Midway Airport on that same date...even though Midway is not an official repoting station.

I have to imagine many places in IL near corn fields have come close to or exceeded 125F on occasion...and in fact aren't too far off from that number with today's heat.

https://climateillinois.wordpress.com/2011/07/19/heat-index-extremes-for-illinois/

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3 minutes ago, beavis1729 said:

Based on this article, 121F is probably a good conservative starting point for Illinois (Peoria on 7/13/1995).

I have to imagine many places in IL near corn fields have exceeded that number a few times...and in fact are close to that number with today's heat.

https://climateillinois.wordpress.com/2011/07/19/heat-index-extremes-for-illinois/

Midway Airport had 124 or 125 on 7/13/1995

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12 hours ago, Hoosier said:

Midway Airport had 124 or 125 on 7/13/1995

  Knoxville, Iowa 131F July 18, 2011

 https://www.wunderground.com/blog/JeffMasters/midwest-heat-wave-generates-a-heat-index-of-131-in-iowa-bret-no-thr.html

Topeka, Kansas 121F July 22, 2017.

http://www.cjonline.com/local/news/2017-07-22/topeka-heat-index-reaches-121

That is probably pretty conservative for Kansas.

 

 

 

 

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8 minutes ago, Knightking2018 said:

  Knoxville, Iowa 131F July 18, 2011

 https://www.wunderground.com/blog/JeffMasters/midwest-heat-wave-generates-a-heat-index-of-131-in-iowa-bret-no-thr.html

Topeka, Kansas 121F July 22, 2017.

http://www.cjonline.com/local/news/2017-07-22/topeka-heat-index-reaches-121

That is probably pretty conservative for Kansas.

 

   Hey Beavis could you please maybe start a list of what we have so far. I like how you write your lists. Thank You!!!!

 

 

 

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**Updated several times as new info becomes available

WI: 149 (Appleton, 7/13/1995)

IA: 131 (Knoxville, 7/18/2011)

IL: 125 (Midway Airport, 7/13/1995)

OK: 125 (Calvin, 7/9/1999)

SC: 124 (Mount Pleasant, 7/13/2011)

KS: 121 (Topeka, 7/22/2017)

AR: 120 (Adams, 8/3/2011)

ME: 114 (Portland, 8/2/1975)

NY: 113 (Fairport, 7/2/2018)

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Don't have the numbers, but for Maine I'd nominate PWM, either 8/2/1975 (103/73) or 7/22/2011 (100/76), their 2 hottest days as measured by daily mean temp.  There was considerable humidity on both days, but I don't have that data.  Their record TD is 77, set in August of 1988, probably sometime on the 5th, which had temps 93/74.

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On 5/31/2018 at 9:04 AM, Knightking2018 said:

I question those dews. AWOS had many issues with dews being too high when they start creeping over 70°. I know you guys get legit dews near 80° during corn season, but while the manned and ASOS sites would be 75-80° you would see AWOS spiting out 85-90° garbage.

Accurate heat index obs will be tough to come by if we include AWOS. I’d toss any obs from them and stick to ASOS or manned.

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1 hour ago, dendrite said:

I question those dews. AWOS had many issues with dews being too high when they start creeping over 70°. I know you guys get legit dews near 80° during corn season, but while the manned and ASOS sites would be 75-80° you would see AWOS spiting out 85-90° garbage.

Accurate heat index obs will be tough to come by if we include AWOS. I’d toss any obs from them and stick to ASOS or manned.

Very good point.  I could see valid Td's near 85, such as what has occurred over the past few days in or near Pontiac, IL (which appears to be taken as valid data by NWS Chicago).  However, 90 may be a stretch, unless the instrument is literally located in the corn field. :) And if this is really true, I guess it would be valid although not very "representative"...kind of like the DCA ob site being in an extreme urban environment. 

Either way, it may be useful to look up some other WI stations on 7/13/1995 to see how high the HI's were...or potentially use the Appleton temp of 101 with a Td of 85 instead of 90??

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1 hour ago, tamarack said:

Don't have the numbers, but for Maine I'd nominate PWM, either 8/2/1975 (103/73) or 7/22/2011 (100/76), their 2 hottest days as measured by daily mean temp.  There was considerable humidity on both days, but I don't have that data.  Their record TD is 77, set in August of 1988, probably sometime on the 5th, which had temps 93/74.

Thank you sir.  

On 8/2/1975, peak HI appears to be 114 at 3PM local (temp 103, Td 72).  This far exceeds 7/22/2011.  I'll go with this for the ME record for now.

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Thanks.  I'm pretty confident that will stand.  A couple stations touched 104/105 in the July 1911 heat wave, but were generally dropping into the 60s at night, so even if there were records of TD (which I highly doubt), the PWM mark looks good.  (Best prospect for 1911 would be Bridgton, Maine, on the 4th, 10th, 11th.) 

As hot as PWM was on that hot Saturday, more amazing to me is the 101 in Bar harbor that day.  It's the one time a swam in Maine's salt water when it actually felt warm.

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6 hours ago, dendrite said:

I question those dews. AWOS had many issues with dews being too high when they start creeping over 70°. I know you guys get legit dews near 80° during corn season, but while the manned and ASOS sites would be 75-80° you would see AWOS spiting out 85-90° garbage.

Accurate heat index obs will be tough to come by if we include AWOS. I’d toss any obs from them and stick to ASOS or manned.

There was a dewpoint of 84 a few days ago if I'm not mistaken in the midwest?

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20 hours ago, beavis1729 said:

**Updated several times as new info becomes available

WI: 149 (Appleton, 7/13/1995)

IA: 131 (Knoxville, 7/18/2011)

IL: 125 (Midway Airport, 7/13/1995)

OK: 125 (Calvin, 7/9/1999)

SC: 124 (Mount Pleasant, 7/13/2011)

KS: 121 (Topeka, 7/22/2017)

ME: 114 (Portland, 8/2/1975)

NY: 113 (Fairport, 7/2/2018)
AK: 100 (Fort Yukon, 6/27/1915)

  Nice!!! Thank You very much!!!

 Here are a few more.

Furnace Creek, California 134F July 10, 1913

Lake Havasu City, Arizona 128F June 29, 1994

Adams, Arkansas  Temp 111F humidity 26% heat index 120F August 3, 2011

https://www.wunderground.com/history/daily/us/ar/little-rock/KLIT/date/2011-8-3

   I need to look more into the heat waves in July and August of 2011 and 2012. I lived back in Emporia, Kansas temporarily and on August 3, 2011 the high was like 112F or 113F. It was baking. 

 

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3 hours ago, Knightking2018 said:

  Nice!!! Thank You very much!!!

 Here are a few more.

Furnace Creek, California 134F July 10, 1913

Lake Havasu City, Arizona 128F June 29, 1994

Adams, Arkansas  Temp 111F humidity 26% heat index 120F August 3, 2011

https://www.wunderground.com/history/daily/us/ar/little-rock/KLIT/date/2011-8-3

   I need to look more into the heat waves in July and August of 2011 and 2012. I lived back in Emporia, Kansas temporarily and on August 3, 2011 the high was like 112F or 113F. It was baking. 

 

These CA and AZ numbers are air temps.  Because it's so dry there, the heat index is typically much lower than the air temp.  I also removed the 100F for Fort Yukon AK, for the same reason.

I'll add AR to the list.  I'm sure they have had a heat index > 120, but we'll use that for now.

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15 hours ago, BuffaloWeather said:

There was a dewpoint of 84 a few days ago if I'm not mistaken in the midwest?

Yes (Olney IL, I believe)...and I even saw an 83 yesterday over the corn fields south of Chicago.

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How often is it that those amazing corn-fed dews occur at night, when the plants are really cranking?  If it's most of the time, a midnight at 85/83 might be trumped by the previous afternoon's 105/75.

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33 minutes ago, tamarack said:

How often is it that those amazing corn-fed dews occur at night, when the plants are really cranking?  If it's most of the time, a midnight at 85/83 might be trumped by the previous afternoon's 105/75.

80 degree dews can occur during the daytime, especially on days with relatively limited mixing.  Sometimes days with pretty good mixing can still pull it off if the low level moisture quality is exceptional.  

It's not uncommon to see a bit of an uptick with the dews in the evening as daytime heating/mixing wanes.  But get too far removed after sunset and it's tougher to maintain the 80+ dews as nocturnal cooling continues.  In my experience it seems fairly unusual to still be seeing obs with 80 degree dews at 3 am, for instance.  

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On 7/5/2018 at 8:23 AM, beavis1729 said:

**Updated several times as new info becomes available

WI: 149 (Appleton, 7/13/1995)

IA: 131 (Knoxville, 7/18/2011)

IL: 125 (Midway Airport, 7/13/1995)

OK: 125 (Calvin, 7/9/1999)

SC: 124 (Mount Pleasant, 7/13/2011)

KS: 121 (Topeka, 7/22/2017)

AR: 120 (Adams, 8/3/2011)

ME: 114 (Portland, 8/2/1975)

NY: 113 (Fairport, 7/2/2018)

   Moorhead Minnesota had a 134F on July 19, 2011.

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