CheeselandSkies

Interestingly, HRRR soundings show some SBCINH ahead of the line of convection as it crosses the Mississippi this evening...but it doesn't kill it off. A case of frontal forcing/dynamics strong enough? Still, may be a limiting factor on gust intensity and tornado production.

Ah. I was focused on the moderate/enhanced.

Doesn't appear SPC made any substantial changes to probability outlines at 1630.

Socked in with fog/low stratus here in Madison. Vis sat appears to show some thinning/clearing over much of Iowa. Not that insolation is a major factor this time of year but any that does happen will only help the thermos overperform more. Might also allow the synoptic winds to mix down more.

Updraft helicity greater than 75 m2/s2, the same product I was referencing in my previous post.

Been a while since I saw a setup where the 3KM NAM sim ref/UH product was more bullish than the HRRR with implied supercell/tornado potential. 12Z HRRR has a solid, narrow line of convection tied to the front with little UH >75. 12Z 3KM NAM for western IA at 12 hrs OTOH...

You're probably thinking of January 2008, same event that had the famous train vs. tornado video from near Harvard, IL.

Tomorrow's system is of the type that could create a substantial regional tornado outbreak if it were April with a wide open Gulf (thinking here of a certain date in 1965). Of course, these days that's always when a winter pattern decides to finally set in.

We'll see...keeping my eye on it.

MKX mentions 55 MPH gusts possible Wed. night in my point forecast. We're not even close to the expected corridor of highest winds, either. @madwx @DanLarsen34 @notsoencrypted I'm actually considering a drive to Iowa Wednesday afternoon to chase synoptic wind, lol. Although that would make the drive home...interesting.

"NO! I WON'T SETTLE DOWN! NOT THIS TIME! I FEEL LIKE...IT'S NEVER GONNA SNOW!"

I have to wonder if the sharp snowpack gradient will help sharpen the warm front in some way. Broyles not impressed by Wednesday due to lack of instability, and he's historically been SPC's most bullish forecaster. That said it seems like SPC loses their nerve in recent years when it comes to hitting cool season events hard, which is unfortunate because in the same timeframe those seem to have been the ones producing high-impact outcomes more often than the high-hype, long lead time spring setups.

I went ahead and uploaded a Google Drive folder with all my GR Level 3 screenshots from this event. When I have time I'll hook up my phone and add all my RadarScope screenshots, mostly from KHPX after it stopped updating on GR Level 3 for some stupid reason (after KPAH was already down for everybody). https://drive.google.com/drive/folders/1XnEHjfxXwljZ-OHkXwkTt0j7wWPfIXwh?usp=sharing First grab of the eventual quad-state supercell is from LZK at 2354 UTC. At 0029/0031 from NQA is when it showed that dramatic BWER which I remarked reminded me of the early stages of the Cullman tornado from 4/27. At 0259 from PAH is when the debris signature explodes again just before Cayce, KY and starting at 0317 is when it starts to approach Mayfield. Unfortunately I went to bed before the Bowling Green tornado.

If I'm not mistaken, that makes it the deadliest single tornado since Udall if not for Joplin, correct? *Although it remains to be seen if the single-tornado toll will exceed Hackleburg or Tuscaloosa.

Guessing all the 12/1/18 had to be in the Lincoln/St. Louis CWAs, then? Still, not terribly far off.

There's also Joplin... but yeah. These are death counts you never want to see in the NEXRAD area (only happened three times before, all within 26 days in 2011); that mean either something went horribly wrong with the warning system/public response, the tornado was extremely, extremely strong, or both.

Ironically though it was '11-'12 that was the dry, snowless winter as I recall. '12-'13 ended up decent at least where I was living at the time (Milwaukee area) but the vast majority of that came after mid-January. Not unlike 2020-'21.

MKX: SPC didn't sound impressed by anything when they put out their 4-8 this morning, but then again they didn't introduce a slight risk for last night's horror show until Wednesday (Day 3 outlook).

Here I assume you're referring to the famous in-cab video from the January 2008 IL outbreak?

I am surprised how much quality video has been coming out of this event given darkness, time of year, storm speeds and HP storm modes apart from the long-track classic monster. I guess I thought more people would have the good sense to not chase due to those factors.

At midnight, in December. Even 12/23 and 12/26/15 weren't this crazy.

Couplet doesn't look as extreme as earlier (Mayfield etc), but still a pronounced TDS at 4,000' from KLVX.

You hate to see that to a beautiful, historic old courthouse.

It cycled at least once south of the TN/KY line.

No updates from HPX or VWX on GR Level 3 since 10:14 CST...but they're working on RadarScope. Very very strange.