Hoosier

850 mb temps pushing 33C in Iowa. Inversion is below this height, so this insane temp doesn't get tapped into. That would pretty much be a heat apocalypse.

Some of the models have what I call Nintendo parameters on Monday... it's almost like you're in a video game and it's not real. Extremely impressive on the NAM in particular, but again the question is how much activity can occur along the front.

Imagine the scenario of going into Tuesday with no electricity and A/C. Heh.

00z HRRR nails northern IL and surrounding areas on Monday.

Likely just a data error when it looks so dramatic like that.

LOT explicity has 80+ forecast for the low at MDW/ORD Tue night-Wed morning. That doesn't happen very often at this lead time as it usually gets raised to that on the day of (or it never gets forecasted at all). Whether or not the low is upper 70s or 80+, it will be a high start for Wed morning as alluded to in my previous post.

Wednesday looks like one of those days where the mild start leads to like 90 around 10 am at ORD and you're thinking hey, is it gonna hit 100 based off of the old school "10 degrees after 10 am rule." But then the warming slows down more than usual in the presence of an airmass aloft that doesn't really support triple digits.

Hey Tip, did you notice the ~30C 850 mb temps making a run for the IA/ IL border on Monday? I can hardly recall that happening, because it has hardly happened, and never in the middle of June. Thing is, that layer is sooo hot/dry that it seems like mixing is largely contained underneath that height on the models.

Let's play a game. Do we see a 100 degree reading at an ASOS or AWOS site in this sub east of the Mississippi River next week? Not extremely confident, but I'll say yes. The most likely place for me would be somewhere in southern/western IL. Wouldn't 100% rule it out at a notorious warm spot like MDW but my guess is that a 98 or 99 peak is more likely there.

What will this map look like in another 10 days?

Although SPC only has 5%, I think there is definitely some conditional sig severe potential. Looking at Monday, while freezing levels are on the high side, any stronger cell would have the potential of dropping some big hail in the presence of very steep mid level lapse rates and high CAPE. How much activity can occur near the warm front is unclear.

I was looking at the RAOB records and it appears that there has never been an 850 mb temp above 25C at DVN in the first half of June. DVN records only go back to 1995. However, the same thing is also true at ILX, and the records for them (and their preceding ob sites) go back to 1949. This will be put to the test coming up.

Progged airmass aloft is pretty extraordinary as it first comes in Monday into Tuesday. Model consensus has very warm/dry conditions aloft with a zone of 850 mb temps in the upper 20s C with even some 30C showing up at the end of the NAM. You'll almost never see that at the longitude of the Mississippi River and when you do, it's not this early in the season. There's some "modification" aloft as we head through Tue and Wed but still pretty anomalous.

Confirmed EF-1

Both the record high and record high minimum look to be in reach for Chicago on 6/15. The records are 95 (kind of a low number compared to surrounding days) and 78... both set in 1994. Records for 6/14 should be safe, but won't be too far off.

I don't know if anything will manage to go near the I-80 corridor on Monday but if it does, look out. Pretty volatile environment.

After a bit of a break late next week, it appears that big heat surges back a few days later.

Who me?

Went out for a stroll... absolutely gorgeous evening. Compared to this upcoming Tuesday when it will probably still be near 90 at this time.

Question for people who see the corn on a regular basis. How high is it right now? I can't imagine it's that tall yet but just curious. I sort of wonder if bringing in this airmass in mid June instead of next month w/more mature corn may allow it to outperform expectations a little bit in the max T department. That is a boiling airmass aloft by time we get to Tuesday and even somewhat pedestrian mixing to 850 mb would suggest some spots in the sub making a run at triple digits.

Quality

Tuesday night-Wednesday morning looks like a decent candidate to not drop below 80 in Chicago. It will be partially dictated by Tuesday's high temp for an elevated starting point and would like to see a high of at least 95 on that day to raise the odds of not dropping below 80 that night. 925 mb temps are progged around 27C Tuesday night-Wednesday morning. I have noticed that it is tough to get nighttime lows much below the 925 mb temp in urban areas when there's a bit of a breeze, which we look to have. 27C is 80.6F, so it gives an idea of where the low could end up. Not a perfect system but an approximation. If it does happen, the issue would be getting that temp to hold all through Wednesday, as it looks like a front will want to slip through late Wednesday or so. As mentioned, Chicago's earliest 80 degree low is in late June... June 28 to be exact. So this would be almost a full 2 weeks earlier.

Do the dew.

Speaking of how record highs in summer have become harder to come by in the last decade or so, here's a breakdown of the number of record highs (including ties) by season for Chicago since 2013. For simplicity, I did this according to meteorological seasons. While it's only one location, I suspect other areas in the sub would also have numbers favoring the seasons outside of met summer. Met winter: 11 Met spring: 7 Met summer: 2 Met fall: 13

It has indeed become harder to set record highs in summer in the Midwest. Other times of year not as hard. I think a lot of it has to do with the land use/farming practices, which has tended to prevent extreme summer max temps while resulting in higher dews (with some exceptions like 2012). Obviously Chicago itself is not a farming mecca, but it doesn't really matter when we're talking about such a large area upstream... it affects everybody.