STORM2K

CAPE is over 2000 in Western Oklahoma, but CINH is showing that it's weakening there too . . .

Friday 4/9 looks interesting. Probably another cap issue but it's still a few days out things could change. Would probably be a pretty big event otherwise... Certainly will be watching for sure.

Upgraded to Enchanced in the Western Half of Dixie Alley . . .

Very broad Slight risk Friday from Texas to Western Alabama


HATCHED area in Northern Texas

Enhanced risk has been expanded. Should be a very messy storm mode today, so any tornadoes are likely going to be QLCS spin ups, which can also be very dangerous

6z GFS Sounding Near Tecumseh, OK on Friday, April 9th



CAPE is between 1500 & 2500 J/kg at that sounding

Do want to mention that the CAPE in Eastern Texas is over 4000 J/kg

Weather Dude wrote:Enhanced risk has been expanded. Should be a very messy storm mode today, so any tornadoes are likely going to be QLCS spin ups, which can also be very dangerous

That seems to be the case, but any supercell that blows up in front of the Squall may produce stronger, long-tracked tornadoes . . .

The net effect should be for
strengthening deep shear (e.g., effective-shear magnitudes reaching
35-50 kt), but also, a more front-parallel component to winds aloft,
encouraging quasi-linear storm mode with embedded supercells and
bow/LEWP features.

Mesoscale Discussion 0322
NWS Storm Prediction Center Norman OK
1110 AM CDT Wed Apr 07 2021

Areas affected...Parts of eastern/northeastern Texas through western
Arkansas

Concerning...Severe potential...Watch likely

Valid 071610Z - 071815Z

Probability of Watch Issuance...80 percent

SUMMARY...The initiation of strong to severe thunderstorms appears
possible as early 1-2 PM CDT. This may, at least initially, include
discrete supercells, before a squall line tends to evolve, and a
risk for tornadoes, one or two of which could be strong.

DISCUSSION...Cloud cover is slowing moist, warm sector
boundary-layer destabilization, but it appears the air mass is
already potentially moderately unstable as the significant upstream
short wave trough begins to take on a neutral to negative tilt
across the central Great Plains. Downstream of the base of this
troughing, beneath increasingly difluent mid/upper flow,
considerable model output suggests that erosion of inhibition
associated with capping elevated mixed-layer air, coupled with at
least some further boundary-layer warming, will allow for the
initiation of thunderstorm development as early as 18-19Z.
Initially this may be largely discrete, and scattered, but focused
within a zone of enhanced low-level convergence along an eastward
advancing cold front.

With the environment becoming characterized by wind profiles with
strong deep-layer shear and sizable, clockwise-curved low-level
hodographs, in the presence of a deep moist boundary-layer, it
appears conducive to supercells capable of producing tornadoes.
This includes potential for a strong tornado or two, though the
overall tornado potential could be mitigated somewhat by relatively
modest high-level flow and the tendency for upscale convective
growth along the cold front through the afternoon.

..Kerr/Hart.. 04/07/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LZK...SHV...TSA...HGX...FWD...EWX...

Severe Thunderstorm Watch #74 for most of Missouri

Iceresistance wrote:Very broad Slight risk Friday from Texas to Western Alabama
https://s4.gifyu.com/images/day3otlk_0730126c7e7de63af04f.gif

HATCHED area in Northern Texas
https://s4.gifyu.com/images/day3prob_0730.gif

I can see why the hatched area was included, 12z gfs shows 4500j/kg in front of that dry line. Given the cap, I would guess this could be a low coverage high intensity event where very isolated supercells could occur in unlucky areas where the cap breaks

cheezyWXguy wrote:

Iceresistance wrote:Very broad Slight risk Friday from Texas to Western Alabama
https://s4.gifyu.com/images/day3otlk_0730126c7e7de63af04f.gif

HATCHED area in Northern Texas
https://s4.gifyu.com/images/day3prob_0730.gif

I can see why the hatched area was included, 12z gfs shows 4500j/kg in front of that dry line. Given the cap, I would guess this could be a low coverage high intensity event where very isolated supercells could occur in unlucky areas where the cap breaks

The Cap only allows the strongest Supercells to form, this may warrant a Enhanced or Moderate risk later on . . .

Tornado Watch #75

Special SPC day 3 outlook adding an enhanced risk has been issued. That does not happen very often

Weather Dude wrote:Special SPC day 3 outlook adding an enhanced risk has been issued. That does not happen very often

This is the first time I've seen that happen . . .

Iceresistance wrote:

Weather Dude wrote:Special SPC day 3 outlook adding an enhanced risk has been issued. That does not happen very often

This is the first time I've seen that happen . . .

I've seen it a couple times before but it's extremely rare

Friday has potential to be big. Especially if the cap breaks further west of the enhanced risk in TX/AR/maybe SE OK. The cap is still the wild card at this point but if it breaks it could be a huge event. I still think it could be an issue, but I think there is a better chance of it breaking than I thought a few days ago. Dixie alley shouldn't have to worry about a cap as usual over there. Either way, a widespread major event looks likely, and Saturday could get interesting also.

Weather Dude wrote:Friday has potential to be big. Especially if the cap breaks further west of the enhanced risk in TX/AR/maybe SE OK. The cap is still the wild card at this point but if it breaks it could be a huge event. I still think it could be an issue, but I think there is a better chance of it breaking than I thought a few days ago. Dixie alley shouldn't have to worry about a cap as usual over there. Either way, a widespread major event looks likely, and Saturday could get interesting also.

What about Central Oklahoma? Is it not likely because it's north of the Low Pressure? But I'm having a feeling that the System desides to trend more north since it's 60 hours out & is currently located over Washington State . . .

Also, the Cap only allows the strongest Supercells to form, this really looks big for sure . . .

Iceresistance wrote:

Weather Dude wrote:Friday has potential to be big. Especially if the cap breaks further west of the enhanced risk in TX/AR/maybe SE OK. The cap is still the wild card at this point but if it breaks it could be a huge event. I still think it could be an issue, but I think there is a better chance of it breaking than I thought a few days ago. Dixie alley shouldn't have to worry about a cap as usual over there. Either way, a widespread major event looks likely, and Saturday could get interesting also.

What about Central Oklahoma? Is it not likely because it's north of the Low Pressure? But I'm having a feeling that the System desides to trend more north since it's 60 hours out & is currently located over Washington State . . .

Also, the Cap only allows the strongest Supercells to form, this really looks big for sure . . .

Central OK could end up with something but right now the models are showing the biggest parameters east of here... For now. Still needs to be watched for sure. Have to watch for a possible triple point set up. As far as the cap, if it's strong enough, nothing will be able to get going, kind of like yesterday in OK. I don't think the cap is going to be anything like yesterday, but it could be enough to prevent a major outbreak. We'll see. It's still a few days out, and we all know that things can change completely between now and then.

Weather Dude wrote:Friday has potential to be big. Especially if the cap breaks further west of the enhanced risk in TX/AR/maybe SE OK. The cap is still the wild card at this point but if it breaks it could be a huge event. I still think it could be an issue, but I think there is a better chance of it breaking than I thought a few days ago. Dixie alley shouldn't have to worry about a cap as usual over there. Either way, a widespread major event looks likely, and Saturday could get interesting also.

Agreed, even yesterday the cap projected further west by the gfs looked insurmountable, but seems to have trended down to a level that can be broken in isolated spots

Today looks like an Enhanced Bust.