andyhb

Holy smokes. Debris to at least 15k feet.

Friday could have significant potential just looking at the progged wind fields overlapping a wide warm sector (pending Thursday's convection). Pretty classic WNW flow hodographs showing up in forecast soundings. Shortwaves with 70-80 kt 500 mb maxes this time of year don't tend to go quietly.

ND/MT/S SK target looks pretty ripe this afternoon with mid-upper 60s dewpoints near the triple point, an arcing dryline, strong ESE surface flow and SE flow at 850 mb pushing 50 kts. Upscale growth would be the main concern, but I'd imagine there will be at least a couple tornadoes in that area later. Further south, moisture is overperforming the HRRR (no surprise) and there's certainly an opportunity for initiation in WY/NE later as a subtle shortwave ejects from the Rockies, although 700 mb temps are quite warm. Certainly a lower probability threat than further north, but could yield something pretty spectacular if it works out.

Here we go again.

You live in Addison TX. Have you not been paying attention to the past week in N TX?

Here's my chase account from yesterday on Stormtrack from what will be a top 5 chase personally for a long time to come. https://stormtrack.org/community/threads/2021-04-23-reports-ar-la-ms-ok-tx.31822/post-371406

Day has some similarities to 4/22 (Springer/Madill) last year being right at the base of the trough with cold air aloft promoting a lot of 0-3 km CAPE and strong updraft accelerations. Ingredients that I'd look for more of are low level flow/moisture depth and also the eastward extent of the warm sector. I'm wondering if some warmer temps closer to I-35 could promote a threat closer to the main LLJ axis, which would raise the tornado threat for DFW north to OKC.

That 12z EPS mean for 4/27 is nasty as hell.

Quality posts. Only the best.

What in the crap are these soundings I'm pulling on Sunday off the NAM/NAM 3 km... 3000 J/kg CAPE in the Mid Atlantic in March (not to mention with a shear profile favorable for sig severe)?

The veering of the surface winds in behind the confluence axis in E MS does give me some pause about the early phase of the event. May take some time to respond to pressure falls associated with the deepening low.

Yeah that's a pretty decided shift on the NAM towards a more organized surface low and slower progression, and that has been taking place since last night.

There is definitely an EML here. Capping and the EML are two different things.

The other 12z CAMs (WRF variants) aren’t quite as high end as the HRRR, but they are certainly more active than the 3 km NAM. ARW and NSSL are probably outbreak scenarios taken verbatim.

Well, safe to say this could be a pretty big event. Convective evolution/mode concerns notwithstanding, there seems to be a consensus across all of guidance for hodographs supportive of long-lived supercells with long tracked tornadoes as early as 15-18z in LA/MS. The degree of low-level moisture is on the high side for this time of year, and I wonder if there may be some subsidence in the late morning following the passage of a potential lead shortwave that could help to suppress junk convection. Any discrete storm in the warm sector that manages to root in that boundary layer by early afternoon is likely going to be a problem. Now it's a question of what wrinkles the mesoscale throws in (and whether the NAM comes around more to the potent solutions suggested by the globals, particularly the UK and Euro).

And probably a strong/violent one.

See you in a few days.

@wizard021 You don't need 1000 m2/s2 SRH to get a threat of significant tornadoes. Please stop with all of this nonsense.

Based on my experience being out there in SW OK as storms tried to develop, this was the case. Every attempt became a turkey tower, and part of it was likely due to all of the smoke in the warm sector limiting insolation (and the capping being stronger than the models had).

I was referring to the 12z runs here. The 18z was definitely less favorable, although there still seems to be some attempts at warm sector initiation.

A hodograph very similar in shape to this (but larger obviously) was in place near the storm that produced the Bassfield MS EF4 last year.

No one said you did. I'm just saying that I don't think the 12z CAMs were really a trend one way or another towards a really muted event ala 5/20/2019. If anything, the HRRR being a little more bearish than some of the WRFs might increase my confidence in a cleaner evolution, lol.

Main question in the SE usually is storm mode given lack of more obvious boundaries, but I'm not so sure that 12z CAM suite was as "grungey" as it would appear, especially a couple of the WRFs. The aggregate/average of them as depicted by the 12z HREF would likely be a significant severe event, with both supercells and bowing line segments. The big question is what does the storm mode look like post-21z when the low-level shear increases significantly. If there are still supercells ongoing by 00z and into the nocturnal period, watch out. The pseudo-cold core regime nearer to the upper low in AR/MO is also worth watching should it be able to destabilize sufficiently.

*Sees the discussion in this thread* *Rethinks life choices to visit it*

Wednesday has the potential to be a widespread severe weather outbreak across the Lower MS Valley/Mid South/ TN Valley/even Lower OH Valley. An expansive EML and high BL moisture content yielding a wide region of destabilization, large area of favorable shear, and moderate forcing for ascent could yield multiple corridors of enhanced potential. Still some uncertainty surrounding the low level wind fields and northward extent, but the signals are rather troubling.