April 24-30th Severe Potential

[OUGrad05]

This, if the VBV doesn't verify it could be possible, but I have my doubts that that would happen. Even if it did SRH would be meager at best.

Interaction with boundaries could add some juice...but as a general forecast?  Agree with you sir.  SRH is mediocre and would put you toward the very bottom percentile(s) of sig tors.

[wildwestpb]

Interaction with boundaries could add some juice...but as a general forecast?  Agree with you sir.  SRH is mediocre and would put you toward the very bottom percentile(s) of sig tors.

An earlier AFD from OUN said shear will remain marginal until 23z, then will increase substantially (their words). They adjusted tornado chance graphics in SW OK, and Western North Texas to account for their thinking at the time. Also thinking there may be an earlier initiation time across western OK and W. North Texas portions of the OUN watch area, which they believe would delay time for storms into central OK.

[David Reimer]

Wouldn't be surprised to see a small 15% tornado introduced in W OK. Things are looking much more interesting with the meso-low developing around Childress to Vernon. That should help back low-level flow and reduce VBV issues. Definitely looking more potent today. Also - check out the 12Z NAM for Friday.

[hlcater]

As others have said, these elevated storms in C OK should produce some weak outflow boundaries and locally enhance tornado probabilities especially when thy cross/intersect with the gravity waves if they are still in a favorable area later this afternoon. Correct? or Incorrect?

[wildwestpb]

Also - check out the 12Z NAM for Friday.

12z GFS looks similar at that time.

[brettjrob]

As others have said, these elevated storms in C OK should produce some weak outflow boundaries and locally enhance tornado probabilities especially when thy cross/intersect with the gravity waves if they are still in a favorable area later this afternoon. Correct? or Incorrect?

 

It's certainly possible. We'll have to see whether these boundaries remain intact or mix out during the next 6-8 hours. One thing working against this scenario just a bit is that convective initiation increasingly looks to occur pretty far west, close to the OK/TX border, so storms may not reach the I-35 corridor until 6-8pm.

[ClicheVortex2014]

Very obvious outflow boundary in NE KS, just as HRRR suspected. Should be some interesting storms up there before they turn linear

[Calderon]

Significant southern extension of the MDT risk putting much of north and part of central TX into play.

[Smokey_mountain_vols]

I swear this morning I was watching channel 6 and literally everything went north or south of Tulsa and almost went around the city. It left me questioning reality. Lol

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[ClicheVortex2014]

5000+ SBCAPE in TX and, locally, it's not even Noon yet.

[RCNYILWX]

Here's a mesoscale update that was posted onto NWSChat by OUN:

NWSOUN Vivek Mahale

Mesoscale update: HRRR wind fields indicate that the forecast dryline bulge is in response of an 850 to 700 mb jet. Current observations upstream at Guadalupe Pass have wind gusts over 40 mph, which suggests this solution may have some merit. The HRRR consistently develops a mesolow on the north side of the dryline bulge. We will continue to monitor observations for the development of the mesolow in SW OK/western north TX.

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[Jim Marusak]

Significant southern extension of the MDT risk putting much of north and part of central TX into play.

just looked at the particulars. they didn't necessarily extend beyond the last update for the tornado risk. what they extended is now a 45% risk area for high wind gusts from Whichita Falls to the Metroplex and Waco. Also Fort Hood might get interesting as well. they must be going on the idea that TX starts just going bow-echo and squall-line crazy.

[boo radley]

I may be wrong, but that hatched TOR area is huge compared to recent enh or mdt days.

[Superstorm93]

I may be wrong, but that hatched TOR area is huge compared to recent enh or mdt days.

That's what happens on days where you have a modest jet streak nosing in aloft over an extremely unstable warm sector.

I think today will definitely come down to important small scale meso features (like OUN pointed out). Those gravity waves have been very interesting this morning/afternoon. Definitely going to be monitoring them as things continue to destabilize.

FYI: GOES is in SRSO for today, which means there a roughly 1-min updates

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[brettjrob]

I may be wrong, but that hatched TOR area is huge compared to recent enh or mdt days.

 

It's really large for a uniform 10% hatched. Oftentimes on high-end days the 10% hatched area will be this large, but with 15%/30% contours inside, so it doesn't look as weird. It's completely appropriate for today, though: an extremely large N-S expanse that has potential for significant tornadoes, but there will probably only be a few storms that actually produce them, with many areas seeing nontornadic storms.

[mfgmfg]

Quite a number of schools have cancelled or let out early in the OKC area today.

[Superstorm93]

WRF-NMM is coming in with more of a focus near the buldge of the dryline in W OK. Looks like things stay relatively discrete for a few hours, then congeal into a large MCS/MCV.

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[boo radley]

Thanks guys! Terrific stuff as always.

[jojo762]

16Z HRRR shows several discrete supercells over S KS/OK at 23Z

[nwohweather]

As others have mentioned Lawton looks like a terrific spot for development. If I was chasing today however I would start at Wichita area and follow any developing storm. Best combination of EHI and CAPE while having discreet cells early on

[wildwestpb]

What do you have going on here in Tulsa tonight? Is it still gonna be bad or am I just going to catch a little bit?

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Hail and winds are a given. According to model consensus as of now, likely it will be some sort of squall line/linear mode as it makes its way into eastern Oklahoma, so, tornadoes within the squall line as still possible, but the hail and wind threat will be readily there.

With as much instability that is in the atmo right now, I would not be surprised to see significant (2+") hail reports and high wind reports well into the overnight hours.

[LocoAko]

Preliminary 18Z sounding out of OUN looks to suffer from much less VBV issues than I would have expected based on NAM, GFS, etc. Though of course surface winds would ideally back more, but that should improve via the isallobaric wind later this afternoon.

[jojo762]

Surface winds and low-level winds will almost certainly back later on... Many models--even though it looks like they are off to a certain degree showed SW/SSW low-level until the later in the afternoon when it began to back more--possibly significantly backed.

[Stebo]

Preliminary 18Z sounding out of OUN looks to suffer from much less VBV issues than I would have expected based on NAM, GFS, etc. Though of course surface winds would ideally back more, but that should improve via the isallobaric wind later this afternoon.

That wind profile off of the 18z sounding is much much better than I expected.

[Chicago Storm]

Preliminary 18Z sounding out of OUN looks to suffer from much less VBV issues than I would have expected based on NAM, GFS, etc. Though of course surface winds would ideally back more, but that should improve via the isallobaric wind later this afternoon.

VBV shows up on the same sounding on COD though. Hmm.

[thewxmann]

^That makes a lot more sense. The lack of inversion on the other sounding was suspicious.

[LocoAko]

VBV shows up on the same sounding on COD though. Hmm.

Hm.... weird. It does also show up in the VAD profile below, though definitely to me seems to be weakening in the 7-10 kft range over the duration of the plot (though we are missing data above 15 kft). I wonder why a discrepancy like that would exist.

From: https://twitter.com/TornadoTitans/status/725027929667698688

[jojo762]

For those who are curious. SPC is answering questions from people on twitter, and still said they are assessing the tornado risk for an upgrade... Also said that a PDS watch was possible too.

[Chicago Storm]

FWD sounding with sig VBV and capping still as well.

[jojo762]

The VBV sig from the most recent scan on that VWP is almost non existent. Doesn't mean that it couldn't come back later on when the shortwave ejects into OK--something to watch, because it could make a huge difference in the tornado threat.