CheeselandSkies

The forecast surface pattern for Tuesday afternoon/evening looks pretty darn near ideal for a significant mid-to-upper MS Valley severe weather outbreak (much as it was on 3/31 last year) and I'm seeing many NAM forecast soundings with large 3CAPE values and strong low-level shear; however there are some caveats. - Most of those NAM soundings also have very wonky wind profiles above 700mb, with sharp backing to due southerly at 500mb followed by veering again but weakening at 300mb. - 18Z GFS wipes out instability across IA/IL with a huge amount of ongoing convection throughout the day. This is likely overdone; but still a legitimate potential fly in the ointment.

IMO, the hype for 4/2 was the stupidest thing I've ever seen in the era of social media weather "forecasting." There was nowhere near the model consistency or agreement on a high-end tornado outbreak; and the trough geometry was totally different than either of the two Super Outbreaks and most of the other known top-tier violent outbreaks. SPC may have inadvertently fueled it by outlining the 15% hatched -driven moderate risk. There are some forecasters there who seem to tailor their outlooks to the "worst-case scenario" rather than the most likely. I disagree with this, but if they feel that's the best way to fulfill their mission to protect lives and property, that's fine.

From the 13Z outlook. Doesn't sound like the kind of wording that should accompany an Enhanced/10% contour.

Decent rain here going to work on those snow piles; should see an explosion of greenery within a few days.

Eclipse forecast seems to have improved for my area. Now looking at "mostly sunny" according to MKX.

I mean, it only goes 24 hours out so you wouldn't have the 10 days of hype. I will say, the simulated reflectivity for the late evening Alabama supercells (that produced Guin, Tanner 1+2, Jasper and Redstone Arsenal) looks somewhat less impressive than I would have expected. Around 02Z-03Z when those storms would have been peaking, it just looks like strung out line segments in the northwest corner of the state, not monster supercells producing some of the most violent tornadoes of what stood as the most prolific tornado outbreak on record for 37 years.

Shows how the 500mb setup for this outbreak was completely different than the one for Tuesday of this week and why the Super Outbreak comparisons to that were silly. To really get those high-end outbreaks you need to see those very wide E-W, neutral to moderately negatively tilted troughs with a broad area of SW-WSW (not SSW) 500mb flow in the exit region spreading out into the warm sector.

Was bored so threw this together using my storm footage across the years over the music video to Van Halen's "Humans Being" from the Twister soundtrack.

God that April sucked. And coming just 4 years after 2014 which similarly had a much BA pattern locked in for the first 6-8 weeks or so of "spring," I was really afraid that was the new normal.

Neither of our major national news partners at work (NBC News, and CNN) have ANY affiliate content available for the 50th anniversary of the Super Outbreak. Zilch. Nada. Another sad reminder that there are severe weather geeks, and then there's everybody else.

Happy to do it, just need something to talk about that doesn't mostly go belly-up on the day (fortunately for the OH/IN/KY area, though). In the meantime, feel free to rewatch my Keota video. 3:08 - 3:38 - 30 seconds is what it took to go from a little tendril of condensation curling around the top of the funnel, to that massive collar cloud that would crown the wedge stage.

Yeah, some of that hype was just stupid. I'm glad I'm not on Twattle-X or the Reeking Muskverse or whatever it is. To be fair to SPC, they have a pretty unenviable task conveying the type of threat that exists on a day like today. Today certainly could have produced a lot more than it did if a few ingredients had lined up better; but the chances of them lining up were pretty slim, if non-zero. Contrast that to a day like March 31 of last year, which had some of the best model agreement I've ever seen in all the years I've been following weather (I wasn't looking at models much in advance of April 27, 2011, and anyway would have known a lot less about what I was looking at). Globals, mesoscale, CAMs all screamed a significant event, differing only in relatively small details of placement and ceiling.

Probably a little of both. The comparisons to 1974 and other ultra high-end outbreaks were ridiculous. This had nothing in common with those other than the general area at risk. Vastly different mid-upper level setup than that which has historically produced the top-tier outbreaks.

Yeah, even on another weather forum I suggested that some people throttle back the hype train a couple days ago, mainly due to the consistently progged steep positive tilt of the main trough and had them jump down my throat because "p0siTivELy tilteD TROughS can STIlL pr0duCe MajoR TOrNaDO events." Well, yeah...BUT it is a lot less likely than with neutral to negatively tilted troughs. I can't confidently say that the mitigating factors we saw with today (and yesterday's) events were direct results of the positively tilted trough, but some (such as boundary-parallel flow promoting junk convection, and the best forcing and cold air aloft lagging behind the warm sector), seem to be common to them.

At least there should be an explosion of green when the weekend/early next week warmup finally hits.

Broyles on today's 4-8: SO WHY DID YOU INTRODUCE AN AREA????!

Well that was a change-up.

I'm just gonna enjoy the nice rain we're having right now.

Video is now live:

Here's hoping Monday is as much of a washout for IA/NW IL as it looks to be on the GFS.

Fair enough.

I have a premiere set up for my 1-year anniversary re-edit/upload of my Keota chase video. Sunday 3/31 at 8:30 AM CDT.

The probabilities on the Day 4 and beyond outlooks don't have a direct correlation to the Day 3 and closer. The 30% zone is for all hazards. For an Enhanced risk, the wind OR hail probability has to be 30% OR the tornado probability of 10%. So it all depends on how things trend and how confident they are. They treat the longer range outlooks a little differently than they used to. Nowadays, they'll introduce a 15% at Day 6 if they're reasonably confident in an at least 15% probability of wind or hail (slight risk) maintaining itself by Day 1. Twenty years ago, if you saw a 25% (then used for a "high-end" slight risk, what would be an Enhanced risk today, the minimum threshold for a slight risk was 15% just like now) contour on the Day 3 outlook, it implied above-average confidence in a widespread/high-ceiling threat and a good chance of a high risk popping up at some point on Day 1.

Ahead of the 1-year anniversary of the 3/31/23 outbreak, NWS Quad Cities has put out a video breaking down the setup for the outbreak in their CWA, including the Keota etc tornado family. One of the frame grabs I sent them is in the graphic at 4 minutes (and on the thumbnail). I was diving a little bit into the archived SPC data earlier this week, and DVN's summary here jives with my impression that this event was surprisingly thermodynamically driven for an early-season Midwest setup. While certainly more than adequate for significant tornadoes given the other conditions in place, the low-level shear (at least in terms of raw SRH values) in this area wasn't jaw-dropping by high-risk, violent tornado outbreak standards. What really put this over the top IMO was the 3CAPE and lapse rates, as well as nearly optimal streamwise vorticity ingestion per the hodograph allowed for maximal use of what spin there was in the atmosphere.