Severe Weather Threat 5/25-5/26, 2024

[UncleJuJu98]

That's some beefy chonkers

 

[Maxis_s]

Yeah I was very much confused by the lack of convection on CAMs, and then I remembered; it's a dryline.

 

[slenker]

Trey from Convective Chronicles doesn’t seem to think that the cap will be an issue, at least in yesterday’s video.

 

[Maxis_s]

Trey from Convective Chronicles doesn’t seem to think that the cap will be an issue, at least in yesterday’s video.

He may have a different opinion if he looks at current model runs, but we'll see.
I think the cap will be an issue for the warm sector, but not so much the dryline.

 

[Maxis_s]

Can you not, HRRR?

 

[Maxis_s]

12z HRRR shows a few discrete cells in the warm sector in OK and KS, but none on the dryline except for a cluster in north KS. Weird, and also very worrying.

 

[tennessee storm chaser]

I'm very very surprised that they made the tornado risk tomorrow so small.

Layer dry air just above playing part that

 

[Maxis_s]

Holy.

 

[cg9450]

View attachment 27661
Holy.

Oh, you've got to be kidding me; this isn't contaminated, is it? ( I don't know how to tell that)

 

[Maxis_s]

Oh, you've got to be kidding me; this isn't contaminated, is it? ( I don't know how to tell that)

Nope, not contaminated. If it is, then just a tiny bit in the upper levels which wouldn't change much.

 

[Maxis_s]

NAM moment

 

[jiharris0220]

Oh, you've got to be kidding me; this isn't contaminated, is it? ( I don't know how to tell that)

It’s contaminated, you can tell by seeing those omega field barbs on the left hand side.

They indicate vertical velocity with height, if they’re present, that means the sounding is either near or in convection.

Also despite the scary looking numbers here, this isn’t actually all that favorable for tornadoes.

Look at the LFC, it’s all the way sky high close to 700mb, well above the effective inflow layer, and far removed from the LCL which means any storm relative helicity that would otherwise feed a tornado is all wasted.

Not to mention the stout cap, which is what’s seen restricting the EIL, and the levels above 700mb are really dry, which can make updrafts thin.

 

[Maxis_s]

I can't tell if models are overmixing and getting things wrong or if there's seriously that much dry air and that much of a capping inversion.

 

[CheeselandSkies]

It’s contaminated, you can tell by seeing those omega field barbs on the left hand side.

They indicate vertical velocity with height, if they’re present, that means the sounding is either near or in convection.

Also despite the scary looking numbers here, this isn’t actually all that favorable for tornadoes.

Look at the LFC, it’s all the way sky high close to 700mb, well above the effective inflow layer, and far removed from the LCL which means any storm relative helicity that would otherwise feed a tornado is all wasted.

Not to mention the stout cap, which is what’s seen restricting the EIL, and the levels above 700mb are really dry, which can make updrafts thin.
View attachment 27663

Very informative notes about the EIL/LFC, thanks for that! I wonder if the SHARPpy hazard algorithm could be modified to account for this and not pop a "PDS TOR" in cases like this, then?

 

[Maxis_s]

Very informative notes about the EIL/LFC, thanks for that! I wonder if the SHARPpy hazard algorithm could be modified to account for this and not pop a "PDS TOR" in cases like this, then?

PDS TOR hazard types have a specific algorithm. I don't quite remember it but I think SHARPpy slightly modifies it, since 4-6km mean wind has to be at least 15kt in the usual PDS TOR requirement/algorithm, but I've seen PDS TOR soundings with 4-6km mean wind under 15kt.
Regardless, I don't focus on the possible hazard type. I don't find it that useful.

 

[Clancy]

12Z CAMs seem most confident in severe potential amongst cells that quickly grow upscale into an MCS across KS/MO tomorrow night, though HRRR pops some very spooky-looking cells across OK. Regardless, wouldn't really wanna be in the path of any storms that form tomorrow afternoon into the night.

 

[Tanner]

Don’t trust anything the CAMS say. With an environment like that, shear vectors perpendicular to the dryline, there will be storms tomorrow.

 

[Maxis_s]

Don’t trust anything the CAMS say. With an environment like that, shear vectors perpendicular to the dryline, there will be storms tomorrow.

The only question is storm coverage and if they might grow upscale, although my guess is that they're not gonna grow upscale.
Is it more likely that we get a very large outbreak of supercells in OK, or just one or two?

 

[cg9450]

It’s contaminated, you can tell by seeing those omega field barbs on the left hand side.

They indicate vertical velocity with height, if they’re present, that means the sounding is either near or in convection.

Also despite the scary looking numbers here, this isn’t actually all that favorable for tornadoes.

Look at the LFC, it’s all the way sky high close to 700mb, well above the effective inflow layer, and far removed from the LCL which means any storm relative helicity that would otherwise feed a tornado is all wasted.

Not to mention the stout cap, which is what’s seen restricting the EIL, and the levels above 700mb are really dry, which can make updrafts thin.
View attachment 27663

Thank you so much for giving me more insight on how to spot that.

 

[Casuarina Head]

Don’t trust anything the CAMS say. With an environment like that, shear vectors perpendicular to the dryline, there will be storms tomorrow.

That’s quite a bold statement. There is a very high likelihood, though not absolute, that nothing will form across most of the warm sector in OK tomorrow. At most I could see one isolated supercell that yields a significant tornado, perhaps two, similar to 6 May. There is simply too little forcing and too much capping for an outbreak of multiple long-lived supercells.

The only question is storm coverage and if they might grow upscale, although my guess is that they're not gonna grow upscale.
Is it more likely that we get a very large outbreak of supercells in OK, or just one or two?

One or two at most, but more likely none. Chances of an outbreak, much less a “very large” one, are close to 0%. Having that said that, I agree with @andyhb that something like 31 May 2013 could still be in play, but only as a “ceiling.” I think SPC’s current D2 outlook is likely to be accurate.