March 2nd Moderate Risk ArkLaTex

[Ed, snow and hurricane fan]

After today's significant Oklahoma outbreak (a derecho and SigTors), March 2nd already 30%.

Thursday afternoon and evening look severe-ish.

[bdgwx]

There are some potent forecast soundings showing up on the 12Z GFS in the OK/TX/AR/LA border area where convection is breaking out. 

[weatherextreme]

There has been plenty of chatter going on about this system, but this board seems to be very quite so far.  I'm very surprised. 

 

 

[weatherextreme]

Pete Delkus

1h  · 

 

Early heads up - strong to severe storms will be possible Thursday. Areas most likely to see the strong storms will be east of I-35 during the afternoon Thursday. Timing/impacts will likely be adjusted in the days to come. Keep checking back in with us!
#wfaaweather

 

[Quincy]

Another potent, compact shortwave, this time with better quality moisture (than yesterday). Forecast soundings from GFS and the Euro pretty alarming across parts of central/east Texas. The signal has been fairly consistent. This will likely trigger another moderate risk from SPC, unless something drastic changes. 

[CheeselandSkies]

It's moving west (as per the NAM, at least). Originally looked exclusively like another lower MS Valley-Dixie event.

[weatherextreme]

15 minutes ago, CheeselandSkies said:

It's moving west (as per the NAM, at least). Originally looked exclusively like another lower MS Valley-Dixie event.

 

How far west is the NAM showing

[Quincy]

Storms developing near I-35 in Texas. 

[DanLarsen34]

Good thread here from a SPC meteorologist discussing how the office currently views high risk issuance.

.

[Ed, snow and hurricane fan]

May be a smidge early to trust NAM at midnight Shreveport time just ahead of the storms, but 2K MLCAPE, 90 knots shear, decent hodo.  Midnight is a bad time for storms.

[CheeselandSkies]

1 hour ago, DanLarsen34 said:

Good thread here from a SPC meteorologist discussing how the office currently views high risk issuance.

 

 

.

They've been very cautious with the high risk in recent years, and rightfully so, as the models and the atmosphere haven't really presented a "slam-dunk" high-end severe setup, and the one time they thought it was (5/20/19) they ended up with huge egg on their face due to a subtle inhibiting factor that none of the models picked up on.

3/25/21 was a pretty good use of the high risk (multiple long-track EF3s, although the lone EF4 came after the high risk had been removed from the updated outlook), 3/17/21 it turned out to be a little overblown IMO.

Of course 4/27/11 kind of gave a lot of people the wrong idea of what a high risk day should be like. There are plenty of more "classic" verified examples but it's been a while since we had one outside of 3/25/21.

11/10/02, 5/4/03, 5/29/04, 2/5/08, 4/24/10, 5/10/10, 5/24/11, 4/14/12, 4/28/14...

[weatherextreme]

We might want to add Wednesday March 1st to this thread as well.  Been seeing where this could possibly go enhanced. 

 

 

[CheeselandSkies]

As of this morning's 12Z runs, NAM is still a good bit further west with the dryline at 0Z Friday compared to everything else, but I think it's closer than it was.

[Ed, snow and hurricane fan]

25 minutes ago, CheeselandSkies said:

They've been very cautious with the high risk in recent years, and rightfully so, as the models and the atmosphere haven't really presented a "slam-dunk" high-end severe setup, and the one time they thought it was (5/20/19) they ended up with huge egg on their face due to a subtle inhibiting factor that none of the models picked up on.

3/25/21 was a pretty good use of the high risk (multiple long-track EF3s, although the lone EF4 came after the high risk had been removed from the updated outlook), 3/17/21 it turned out to be a little overblown IMO.

Of course 4/27/11 kind of gave a lot of people the wrong idea of what a high risk day should be like. There are plenty of more "classic" verified examples but it's been a while since we had one outside of 3/25/21.

11/10/02, 5/4/03, 5/29/04, 2/5/08, 4/24/10, 5/10/10, 5/24/11, 4/14/12, 4/28/14...

Looking at the 12Z GFS point soundings, EHI, etc., this wouldn't be a Day 1 Mod or High.  NAM is 'better'. but at 60 hours, not quite in the wheelhouse.  NAM is slower/farther West has better point soundings, higher EHI, but still not High risk, IMO.  If the NAM stays consistent as the event approaches, Moderate seems doable.

[stormdragonwx]

Indeed I'm thinking tomorrow might be a decent day before the day type setup. HRRR has been consistent on tracking a lone supercell over southern AR.

[yoda]

 

 

[weatherextreme]

9 minutes ago, yoda said:

 

 

 

Very strong wording from the local Little Rock NWS.  Don't see that very often

[cheese007]

Latest from FWD. They seem skeptical of storms forming ahead of the line and are talking about our old friend VBV limiting Tor potential. Bolding is mine

 

Concerning the severe weather threat(s): The primary threat early
in the event will be large hail due to steep lapse rates and
strong bulk shear and a more isolated convective/supercellular
mode. Once the convection congeals into a line the threat will
shift to primarily damaging winds with brief/embedded tornadoes.
It should be noted that the tornado threat appears less impressive
than prior model runs. One thing about the synoptic setup that is
not favorable for tornadoes is the flat/zonal 850mb pattern
across the southeastern US. A more favorable tornado setup would
feature ridging in this area. The implications are that this will
cause the 850mb cyclone to develop eastward very rapidly, and out
of phase with the main upper level trough and its forcing. As a
result the low level jet will shift east into the Lower
Mississippi Valley Thursday afternoon causing hodographs across
North and Central Texas to lose their cyclonic shape before the
forcing and boundary arrive. These more disorganized wind profiles
will feature veering winds, then backing winds, and then veering
winds again as height increases. While veer-back-veer profiles
still can support severe weather, and even tornadoes, they don`t
tend to support the strong or long-track tornadoes and can inhibit
low level mesocyclone intensification for very large hail
production. Still given the parameter space, we`ll need to
advertise all severe hazards with this event since a brief/weak
tornado is still a pretty big deal if it impacts your location
regardless if it`s delivered via supercell or QLCS.

 

[Quincy]

The potentially alarming thing about Thursday in Arkansas is the placement of a warm front/boundary along the Arkansas Valley. This is a locally specific setup that results in geographically enhanced channeling of backed low level flow near I-40 from Fort Smith to Little Rock. Such setups have produced some significant, long track tornadoes.

Think 75-100 knot, SW 500mb flow backing to SE near-surface winds, along with a southerly LLJ increasing to over 50 knots with sufficient instability. Yikes. 

[nwohweather]

11 hours ago, DanLarsen34 said:

Good thread here from a SPC meteorologist discussing how the office currently views high risk issuance.

 

 

.

 

 

Great read. Also interesting to see violent tornadoes being mentioned a couple days out

[Ed, snow and hurricane fan]

Thursday 6 pm, Veer-Back-Veer mentioned above on 3 and 12km NAM soundings in DFW.  80 knots 12km/90 knot 3km deep shear and ~1600 J/Kg MLCAPE on both.  I think (I need to watch a You Tube to make sure I'm doing it right) WBZ is around 3 km, a tad high for hail per internet, but who knows.  90 knots shear

[yoda]

MOD RISK for morning Day 2

[yoda]

Large area of hatched tor probs and wind probs

 

[yoda]

Dallas/Fort Worth is right on the border of ENH/MOD... SHV is inside MOD risk... Little Rock is in the ENH but MOD is just off to their SW

[yoda]

Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1259 AM CST Wed Mar 01 2023

   Valid 021200Z - 031200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR NORTHEAST
   TEXAS...FAR SOUTHEAST OKLAHOMA...SOUTHERN ARKANSAS...NORTHERN
   LOUISIANA...

   ...SUMMARY...
   A regional severe-thunderstorm outbreak appears possible across
   parts of the southern Plains into the ArkLaTex and ArkLaMiss regions
   Thursday into Thursday night, with a few strong tornadoes,
   widespread damaging wind, and hail all possible.

   ...Synopsis...
   A deep mid/upper-level trough is forecast to become negatively
   tilted as it traverses the southern Plains on Thursday. A surface
   low is expected to steadily deepen somewhere near the Red River
   during the day, with more rapid deepening expected Thursday night as
   the cyclone moves northeastward toward the Ozarks. 

   ...Southern Plains into the ArkLaMiss region and Southeast...
   A regional severe-thunderstorm outbreak still appears possible from
   parts of the southern Plains into ArkLaMiss vicinity, mainly
   Thursday afternoon into Thursday night. A Moderate Risk has been
   introduced where confidence is currently highest in the potential
   for widespread damaging wind and a few strong tornadoes. 

   Early-day convection appears possible across north Texas into the
   ArkLaTex region and parts of the ArkLaMiss, which may persist
   through much of the day and limit the northward progression of the
   effective warm sector. Meanwhile, moderate instability will develop
   along/ahead of the cold front across parts of north/central TX,
   which will begin to surge eastward by late afternoon into the
   evening. Renewed thunderstorm development along the front will be
   possible as soon as mid afternoon, with coverage increasing markedly
   by early evening. A QLCS will likely develop and surge eastward
   toward the ArkLaTex region, and eventually toward the ArkLaMiss
   overnight.

   Strong deep-layer shear will be present across the entire region
   through the period, with low-level shear/SRH expected to increase
   near the ArkLaTex region by early evening, in conjunction with an
   intensifying low-level jet. Any early-day convection that can become
   rooted in the boundary layer could evolve into organized
   cells/clusters, with an attendant threat of all severe hazards.
   Uncertainty remains regarding the coverage and location of discrete
   warm-sector supercell development during the afternoon/evening,
   though that remains possible. Embedded supercells will also be
   possible within the QLCS that develops along the surging cold front.

   A few strong tornadoes (and also large hail) appear possible with
   any sustained discrete or embedded supercells that move into an
   increasingly favorable environment near the ArkLaTex region.
   Widespread damaging winds may also evolve with the anticipated QLCS
   Thursday night, along a with a threat of line-embedded tornadoes.
   Storms may tend to weaken late in the period, as they encounter
   weaker instability and the primary shortwave begins to eject away
   from the warm sector, but some threat for damaging wind and at least
   brief tornadoes will likely persist until the end of the period into
   parts of central/northern MS.

   ..Dean.. 03/01/2023

[CryHavoc]

Ominous wording from the SPC.  I would guess the Day 1 issuance will stay MDT at this juncture.  Seems to be enough questions around the timing and shear to make a high risk somewhat unlikely.

[canderson]

Parents in ET are in for a rough one. They've been targeted several times over the past three years with tornadoes, just can't catch a break. 

[Powerball]

Definitely think the Severe Thunderstorm Watch for all of DFW was a bit presumptuous. The activity this morning has been centered along a narrow corridor and has shown no signs of expanding northward or southward. In other words, it's isolated enough that short fuse warnings would have been sufficient.

[bdgwx]

SREF says tornado ingredients are higher today than tomorrow.

[Quincy]

Have to wonder if this early convection lays down an outflow boundary for renewed storm development this afternoon in northeast Texas. At the very least, it will reinforce the frontal boundary and probably keep afternoon storms a bit further SE than some earlier progs were showing.

Tomorrow, the models looks increasingly like an I-35 mega QLCS as the main show, although isolated warm sector activity cannot be completely ruled out.