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Hoosier

September 2017 Record Breaking Heat Wave

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1 hour ago, Hoosier said:

 

Heat index map

sfctapp.us_mw.thumb.png.d904640d435ebcd03e792f916b7c45f6.png

Looking pretty toasty.  Point looks a bit conservative with 88 being forecast.  Think 90 is doable but 93 looks bullish considering southerly surface flow and dews pushing 70.  Pretty impressive for late Sep though.

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3 minutes ago, cyclone77 said:

Looking pretty toasty.  Point looks a bit conservative with 88 being forecast.  Think 90 is doable but 93 looks bullish considering southerly surface flow and dews pushing 70.  Pretty impressive for late Sep though.

Will be curious to see if dews mix out more than NAM.  GFS does, and the result is temps even a couple degrees warmer with the raw output of 95 for MLI.

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1 hour ago, cyclone77 said:

Given how dry it is it really wouldn't surprise me.

NAM and GFS both have 850 mb temps around 21C out there.  If that verifies then mid 90s would certainly be in play.  Some caution is warranted as MLI has hit 95 or higher only 4 times on/after September 20, but that is one heck of a thermal ridge being progged for this time of year and with dry ground, who knows. 

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KCMI tagged 90 again yesterday, second day in a row, have to wonder if the extremely dry conditions are aiding the temperatures. 

 

I now have 90-92 degrees in my forecast Wednesday-Saturday. With little to no rain. 

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Here are the 10 warmest days in Chicago, September 20th and later.  Strangely enough, the two warmest days are later in the season than most of the other eight days.  Just goes to show how "jumpy" outlier/extreme events can be.

99 on 9/29/1953 :o

94 on 10/6/1963 :o

92 on 9/30/1971, 9/28/1953, 9/22/1956, 9/21/1970

91 on 9/27/1971, 9/24/1891, 9/23/1937, 9/20/1931

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3 minutes ago, beavis1729 said:

Here are the 10 warmest days in Chicago, September 20th and later.  Strangely enough, the two warmest days are later in the season than most of the other eight days.  Just goes to show how "jumpy" outlier/extreme events can be.

99 on 9/29/1953 :o

94 on 10/6/1963 :o

92 on 9/30/1971, 9/28/1953, 9/22/1956, 9/21/1970

91 on 9/27/1971, 9/24/1891, 9/23/1937, 9/20/1931

What in the world was happening on 9/29/53?  Crazy stuff.

I was going to roll out some stats, if and when ORD hits 90, but might as well do it now.  I researched this a couple days ago and don't have it in front of me but I believe Chicago has hit 90+ a total of 34 times from September 20 onward, which makes it about 1 day per 4.3 years for the long term average... though lately it has been more like 1 in 10 years. 

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55 minutes ago, beavis1729 said:

Here are the 10 warmest days in Chicago, September 20th and later.  Strangely enough, the two warmest days are later in the season than most of the other eight days.  Just goes to show how "jumpy" outlier/extreme events can be.

99 on 9/29/1953 :o

94 on 10/6/1963 :o

92 on 9/30/1971, 9/28/1953, 9/22/1956, 9/21/1970

91 on 9/27/1971, 9/24/1891, 9/23/1937, 9/20/1931

Didn't even think the atmosphere had it in itself to get that warm on Sept 29.

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5 hours ago, beavis1729 said:

Here are the 10 warmest days in Chicago, September 20th and later.  Strangely enough, the two warmest days are later in the season than most of the other eight days.  Just goes to show how "jumpy" outlier/extreme events can be.

99 on 9/29/1953 :o

94 on 10/6/1963 :o

92 on 9/30/1971, 9/28/1953, 9/22/1956, 9/21/1970

91 on 9/27/1971, 9/24/1891, 9/23/1937, 9/20/1931

Here's a list of all of Chicago's 90 degree days from September 20 on, according to day.  As you can see, 17 of the 34 occurrences happened between Sep 20-22. 

9/20:  7

9/21:  5

9/22:  5

9/23:  1

9/24:  3

9/25:  1

9/26:  1

9/27:  1

9/28:  2

9/29:  1

9/30:  1

10/1:  1

10/2:  1

10/3:  2

10/4:  1

10/6:  1

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LOT forecast has 88-90 for ORD for the next 4 days.  The record streak of 90 degree days from 9/20 onward is 3 days, from 9/30/1971 through 10/2/1971 and 9/20/1895 through 9/22/1895 (though that one started on the 19th).  Even if a 3 or 4 day streak of 90s fails to materialize, the current forecast (getting the 4th consecutive day of at least upper 80s) would basically be an unprecedented occurrence in Chicago weather records.  The max temps are noteworthy, but it's really the duration of this high end warm stretch that is more unusual.  

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On 9/19/2017 at 6:18 PM, Hoosier said:

LOT forecast has 88-90 for ORD for the next 4 days.  The record streak of 90 degree days from 9/20 onward is 3 days, from 9/30/1971 through 10/2/1971 and 9/20/1895 through 9/22/1895 (though that one started on the 19th).  Even if a 3 or 4 day streak of 90s fails to materialize, the current forecast (getting the 4th consecutive day of at least upper 80s) would basically be an unprecedented occurrence in Chicago weather records.  The max temps are noteworthy, but it's really the duration of this high end warm stretch that is more unusual.  

 

Wonder how high ORD reached back in Oct, 2007 - 5-7th   That was a  great stretch of sept in to oct wx. Heck - we've had a great run of early falls for awhile now and this fall fits the bill for another.  Let this fall behave like Nina's tend to and then let's let the parade of cutters begin.

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23 minutes ago, UMB WX said:

 

Wonder how high ORD reached back in Oct, 2007 - 5-7th   That was a  great stretch of sept in to oct wx. Heck - we've had a great run of early falls for awhile now and this fall fits the bill for another.  Let this fall behave like Nina's tend to and then let's let the parade of cutters begin.

4th to 8th was 82, 84, 87, 87, 87

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Thanks.  That must be pushing +20 - impressive. To go on to one of the best winters in history. Sweet stretch of wx we've been in outside the local meh winters of late.  That's fixing to change though.

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6 minutes ago, cyclone77 said:

HRRR pretty bullish with temps tomorrow for this area.  Showing 91-93 for the QCA.  The record at MLI for tomorrow is 92 from 1931.  May give it a run if the HRRR is correct.

Record mins are probably going to be threatened in the next several days as well. A wildcard would be in areas with very dry ground and whether that allows bigger overnight cooldowns than progged.

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9 minutes ago, Hoosier said:

Record mins are probably going to be threatened in the next several days as well. A wildcard would be in areas with very dry ground and whether that allows bigger overnight cooldowns than progged.

Yeah the relatively high dews for this late in the year should help keep those temps up.  It's amazing to think that we're not too far from the earliest trace snowfall for this area, and we could conceivably see heat index temps pushing 100 tomorrow.

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HRRR dews at 21z.  I'd have to check but I wonder how this compares to what happened in Oct 2007.  Then again, that was a couple weeks later in the calendar year.

sfctd.us_mw.thumb.png.ec58607dad2241ad63fe742d391ca5b2.png

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Was wondering if the rains overnight yesterday would have any effect in holding back temps around here, but it doesn't look like it.  Checking a couple of the nearby sites, they are running very close to the Chicago sites which got very little rain, and the Chicago sites had a warmer start this morning.

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87 at ORD.  Should be able to reach 90 today.  

Warmer start tomorrow with a very similar airmass overhead may put something like 92 or 93 in play.

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Wow 94 now, which should break the record from 2010. Stepdads personal weather station just south of champaign in a rural area is recording 95. Insane. 

 

Edit: I was wrong. We have tied the record from 1891. C’mon baby let’s break it 

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27 minutes ago, Chambana said:

Wow 94 now, which should break the record from 2010. Stepdads personal weather station just south of champaign in a rural area is recording 95. Insane. 

 

Edit: I was wrong. We have tied the record from 1891. C’mon baby let’s break it 

I'd lean more toward the highest model 2m temps in the coming days, especially with the generally dry ground.  MAV/MET MOS output is still tending to undershoot, even on the day of (like today).  Old school forecasting "10 after 10" rule (add 10 degrees to the 10 a.m. temp to get the high, on days without strong advection and drastic change in sky cover) undersold the warming potential today as well, with many areas rising more like 12-15 degrees.

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