Severe Weather Threat 01/24/23-01/25/23

11z Update:

PC AC 241255



Day 1 Convective Outlook

NWS Storm Prediction Center Norman OK

0655 AM CST Tue Jan 24 2023



Valid 241300Z - 251200Z



...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE MIDDLE

TEXAS COAST TO THE WESTERN FLORIDA PANHANDLE...



...SUMMARY...

Severe thunderstorm winds and a threat of tornadoes are expected

today near the middle/upper Texas Coast, then eastward tonight

across coastal areas of Louisiana, Mississippi, Alabama, and the

western Florida Panhandle.



...Synopsis...

The main mid/upper-level feature for this forecast will be a

synoptic-scale trough attendant to a compact cyclone now centered

over the LRU/ELP vicinity. The 500-mb low is forecast to move

east-northeastward to near DFW by 00Z, with trough positively tilted

southwestward across central/southwest TX and northern MX. By 12Z,

the mid/upper low should reach the Mississippi River in the STL-CGI

region, with the trough across the Ozarks and central TX to

Coahuila. As this occurs, a broad belt of locally very intense

cyclonic flow aloft will extend from the Great Basin and northern MX

across the western/central Gulf Coast region, shifting eastward

along the coast as the main vorticity lobe ejects across eastern OK,

AR and southern MO tonight.



At the surface, 11Z analysis showed a low over northern Coahuila,

with cold front roughly southward across northeastern MX, and warm

front eastward over deep south TX (just north of the lower Rio

Grande Valley) and the northwestern to central Gulf. The low should

move/redevelop northeastward to a position in the CLL/IAH area by

18Z today, to west-central LA by 00Z, then outpacing the inland

advance of the warm sector and moving across the Mid-South to near

PAH by the end of the period. The trailing cold front should extend

near a LCH-BRO line by 00Z, then from eastern AL across the western

FL Panhandle to the southwestern Gulf by 12Z tomorrow. The warm

front should move to very near, or just inland from, the immediate

upper TX and LA coastlines through this evening, then diffusely

somewhat further inland across MS/AL/FL Panhandle tonight.



...Gulf Coast...

A few supercells may develop over the Gulf throughout the period and

move ashore in the prefrontal/warm sector, on either side of the

surface warm front. Any such cells interacting with the front over

land, or in the warm sector, will be in a favorable buoyancy/shear

parameter space for a tornado threat, and large hail will be

possible from relatively discrete cells over the western Gulf

Coastal plain where deep-layer lapse rates will be greatest.



The bulk of convection, however, is expected to occur as part of a

quasi-linear convective system (QLCS) organizing from midday into

afternoon, perhaps evolving from previously elevated, midmorning to

midday convection over south-central TX. As this activity shifts

eastward over the middle/upper TX Coastal Plain, and begins to

interact with the destabilizing warm-frontal zone and warm sector,

it should intensify to severe levels, offering mainly damaging wind

and a few tornadoes with embedded bow/LEWP features and

mesovortices.



Increasingly buoyant air is expected in the boundary layer the QLCS

will encounter near the coast this afternoon and evening, with upper

60s to low 70s F surface dewpoints common along and south of the

front. This air mass will underlie seasonally steep midlevel lapse

rates over the western parts of the outlook area, thanks largely to

a modest EML (apparent in the 12Z BRO RAOB, but with only a weak

basal stable layer) originating over the Mexican plateau. MLCAPE of

1000-1500 J/kg is expected near the mid/upper TX Coast and is

possible a short distance from the Gulf into southern LA. Mass

response to the cyclone/trough aloft will foster strong deep-layer

winds, with favorable deep shear and low-level hodographs. The

latter will become large area-wide, shifting eastward ahead of the

QLCS, with effective SRH of 250-400 J/kg being common near the warm

front. An intense (50-70-kt) LLJ near the coast will expand the

hodograph near the warm front enough to support locally higher

effective SRH as well.



The direct influence of the EML will wane gradually with eastward

extent as the QLCS crosses LA/MS/AL to the western FL Panhandle;

however, boundary-layer theta-e near the coast should be enough to

maintain a deep CAPE profile. In fact, low-level warm advection and

moisture transport should enable the QLCS to expand inland in the

low-level warm-frontal zone, which will be characterized by

gradually stabilizing near-surface air poleward. That stabilization

will render severe-wind and tornado potential more conditional with

inland extent, though isolated events are possible as far inland as

central parts of MS/AL.



..Edwards/Goss.. 01/24/2023

Sounding from Corpus Christi this morning 

Just pointing out the strong low level jet already in place this morning along the lower TX coast with change in direction with height along with a 130 knot upper level jet streak over it.

Are there any limiting factors at all for along the coastal areas?

Was surprised to hear a clap of thunder already this morning