Chicago Storm

A mixed convective rain/snow/graupel shower fest today, and possibly tomorrow as well. .

Had a view of a wall cloud here at ORD between 5:40-6:10PM, associated with a severe t'storm warned supercell structure that tracked across Kane and Northern Cook Counties.

some of ya'll need a touch with reality. outside of 2018, april tends to be what april should be. ...April 60+/70+/80+ Days & Monthly Average By Year For Chicago... April 2023 (Thru 4/19) 60+: 13 70+: 7 80+: 4 Month Average: +6.8 April 2022 60+: 9 70+: 3 80+: 1 Month Average: -2.7 April 2021 60+: 15 70+: 8 80+: 3 Month Average: +2.2 April 2020 60+: 14 70+: 4 80+: 1 Month Average: -1.3 April 2019 60+: 14 70+: 5 80+: 1 Month Average: 0.0 April 2018 60+: 8 70+: 1 80+: 1 Month Average: -8.5 April 2017 60+: 19 70+: 11 80+: 1 Month Average: +4.0 April 2016 60+: 12 70+: 8 80+: 2 Month Average: -1.9 April 2015 60+: 16 70+: 3 80+: 0 Month Average: -0.3 April 2014 60+: 14 70+: 5 80+: 1 Month Average: -1.1 April 2013 60+: 11 70+: 3 80+: 1 Month Average: -2.8 April 2012 60+: 16 70+: 3 80+: 0 Month Average: +1.0

The difference actually isn’t the lake in this case, with a 5-10MPH westerly wind at ORD. I’d guess it’s more of a case where IND being on the edge of the metro/rural land, with a W-erly wind/less UHI, is making the difference. .

We saw a similar period during the 1st half of March. During that period we saw a mix of mild (AA) and cool (BA) temps, with an average to above average active pattern. So all in all, this could be similar, just a solid month+ later in the year.

The EPO isn't going negative in any significant or consistent way, and the PNA won't be going positive in any significant or consistent fashion either. As you mentioned though, we will be seeing a -NAO/-AO pattern for this 2nd half of April. Pair that with a EPO/PNA that are going to be in flux throughout, and an MJO steadily sliding through phases 7-8-1-2. This will lead to more a classic spring/April rollercoaster pattern for this 2nd half of April, and into the start of May as well. Bouts of mild and cool temperatures are to be expected, with an average to above average pattern in terms of activity.

or not. still will end up with more 70+ days (and 80+ days) than tenths of an inch of total snow, so there's that.

cancel that. jinxed those.

The tornado count from the March 31st outbreak in Illinois now stands at 37, making it the 2nd largest tornado outbreak on record for Illinois. DVN is still combing through things, so that number could still change. March 31st, 2023: LOT: 17 DVN: 6 ILX: 12 LSX: 2 EF-U: 4 EF-0: 9 EF-1: 16 EF-2: 7 EF-3: 1 Biggest Illinois Tornado Outbreaks: 1. 39 - 4/19/1996 2. 37 - 3/31/2023 3. 35 - 4/2/2006 4. 29 - 12/1/2018 5. 25 - 11/17/2013

The only other two 'triple dip' La Niña occurrences (1974-76 & 1999-2001) were followed by neutral ENSO summer conditions. So this will be new and unknown territory we are entering.

As posted in the Chicago records thread... ORD had a high temperature of 83° today, which broke the record high temperature for the date of 82°, which was set in 1887 and 1941.

ORD had a high temperature of 83° today, which broke the record high temperature for the date of 82°, which was set in 1887 and 1941.

It's not often that you see a full week with temps in the 70's and 80's in mid-April, without any sort of lake breeze...Whether it be in April, May or June. Managed to do it earlier this week with light winds, but good gradient alignment. Now as we have transitioned into mid week, and continuing into late week, stronger winds are preventing development.

MDW hit 80 for about 2 minutes.

Final event (April 4th & 5th) tornado count of 9 in IL.

It’s currently 93° in Pierre, SD and 50° in Aberdeen, SD…With a difference of 150 miles between both locations. That’s probably one of the sharper non-frontal boundary gradients you’ll ever see. Check out the significant inversion on the HRRR simulated sounding, from along the SD/ND border this afternoon.

And we're back with some new ones to watch... Earliest Last Measurable Snowfall Of A Season: 1. 1994 - 2/28 2. 1985 - 3/3 3. 2012 - 3/4 4. 1945 - 3/6 5. 1953 - 3/8 6. 1946 - 3/9 6. 1919 - 3/9 8. 1999 - 3/10 9. 1963 - 3/12 10. 2023 - 3/13 Least Seasonal Total Snowfall: 1. 9.8" - 1920/21 2. 11.5" - 1921/22 3. 12.0" - 1936/37 4. 14.3" - 1948/49 5. 18.0" - 1898/99 6. 18.2" - 1901/02 7. 18.9" - 1924/25 8. 19.0" - 1914/15 8. 19.0" - 1912/13 10. 19.7" - 2022/23 (11. 19.8" - 2011/12)

welcome to the 0 meter club.

Haven't had a chance to put out any April thoughts with the active severe weather pattern ongoing, but... Spring is here for April, let's just put it that way. We are losing a lot of the ridging that has been in place up north, which was shunting the remaining cold air down into our region. I feel highly confident in saying Chicago has seen it's last accumulating snow for the season, which was back on 3/13. There's a better chance of racking up numerous 70+ days this month than seeing more accumulating snowfall.

Forgot to mention... This past Friday (3/31) was not only the first 60+ day of the year at ORD, but it was also the first 70+ day as well.

I'll be unable to chase this afternoon/evening due to work, as I had a decision between chasing today or Friday, and chose Friday. If I were able to, I would most definitely head out towards the IL/IA border, in anticipation of the afternoon/evening round of potential development in the vicinity of the warm front. Might still attempt to make a play on this morning/midday round if it moves in quick enough, and looks to be producing quality damaging winds/hail still.

They do. Risk level is coverage based and hatching is for significance. Their system is still quite flawed, though.

3/31 and 4/1 were two separate events, and wouldn't really consider either day to have had a derecho. 3/31 featured mixed mode, which produced corridors of damaging winds. 4/1 had two separate complexes, neither of which had the distance/longevity.

For now. Could readjust as I get closer. .

I’m about 30 minutes ahead of you. .