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ACUS01 KWNS 091648

SWODY1

SPC AC 091646



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

1146 AM CDT Thu May 09 2024



Valid 091630Z - 101200Z



...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM CENTRAL

TEXAS EAST ACROSS THE CENTRAL GULF COAST STATES AND INTO SOUTHERN

GEORGIA AND SOUTHERN SOUTH CAROLINA...



...SUMMARY...

Very large hail with multiple supercells appears probable across

parts of north and central Texas into the ArkLaTex vicinity this

afternoon and evening.  A broader corridor of severe hail and

damaging-wind potential will extend from east Texas into the lower

Mississippi Valley and Southeast.



...Synopsis...

Water-vapor imagery late this morning shows a mid-level trough over

the western Great Lakes/Upper MS Valley and a mid- to upper-level

low situated over eastern UT.  A broad belt of strong westerly

500-mb flow will extend from the Desert Southwest eastward across

the southern Great Plains and to the Mid-Atlantic and Southeast U.S.

coast.  Satellite imagery also depicts an embedded disturbance

quickly moving east across AL into western GA late this morning. 

Another upstream disturbance is currently moving east-northeast

across northern Mexico into the Rio Grande Valley/Edwards Plateau

late this morning.  In the low levels, a surface low over the OH

Valley is largely displaced from the area of greatest severe

thunderstorm concern today, which is located from TX east to the

GA/SC vicinity.  A myriad of ongoing thunderstorm bands and

convective outflow over the Southeast will serve as corridors for

additional and continued thunderstorm activity through at least the

early to mid afternoon.  Farther west, a dryline and west-east

oriented frontal zone over north TX east to the ArkLaMiss will also

act to focus severe thunderstorm development later today and

tonight.



...North, central and east TX...

Scattered thunderstorms are forecast to develop this afternoon and

evening ahead of the aforementioned mid-level disturbance across

central and eventually into eastern portions of TX.  Storm

development will likely initially favor near and north of a frontal

zone draped across north TX with dryline storms later this

afternoon.  The Fort Worth and Del Rio, TX raobs sampled 8-9 deg

C/km 700-500 mb lapse rates.  Very large CAPE via a very moist

boundary layer will likely favor explosive updraft growth as storms

quickly become supercellular.  Low-level shear will likely be

subdued due to lack of a strong low-level mass response, thereby

acting to limit overall tornado potential.  Nonetheless, a few

supercells within an environment characterized by very large

buoyancy and moist low levels will potentially yield some tornado

risk via local storm-scale processes such as mergers and boundary

interactions.  Large to giant hail --potentially 3+ inches in

diameter -- as well as locally severe gusts and perhaps a tornado or

two will be the primary threats.  The wind threat could evolve

upscale and start forward-propagating eastward into LA wherever

early cells can aggregate into clusters.  QLCS tornadoes are also

possible with any MCS.



...Southeast...

Bands of strong to severe thunderstorms ongoing during the midday

will likely continue to propagate east-southeast across eastern AL

into GA and SC.  A very moist/unstable airmass evident in the 12z

Birmingham and Atlanta raobs (1800 and 1300 J/kg MLCAPE) will

continue to gradually destabilize, despite considerable cloud

coverage across AL/GA.  Fewer clouds across south-central GA into

the coastal plain of SC will continue to heat more rapidly

downstream of the ongoing storms and yield an environment favorable

for a continued damaging-wind risk through the mid to late

afternoon.  For short-term convective details and environmental

analysis, please refer to MCD #728 and forthcoming MCDs over the

region.



Farther west, from western AL westward into LA this afternoon, weak

large-scale subsidence in wake of the AL/GA impulse will probably

act to limit storm coverage during the day.  Isolated severe storms

are possible as the airmass continues to destabilize and potentially

yield an isolated hail/wind threat.  Later this evening into the

overnight, a cluster of thunderstorms is forecast to evolve over the

Arklatex and move east across LA into MS and eventually MS/AL/FL

Panhandle.  Severe gusts (60-85 mph) and the risk for a few

tornadoes will probably accompany this activity as it moves east

during the evening and overnight.



...Mid/upper Ohio Valley to Tidewater...

Isolated to widely scattered thunderstorms are possible this

afternoon across portions of the OH Valley, with damaging gusts and

marginally severe hail possible.  Some heating coupled with lower

60s surface dewpoints will contribute to MLCAPE ranging from

500-1500 J/kg.  Though upper flow will be strong, nearly

unidirectional profiles and lack of greater midlevel winds should

keep effective-shear magnitudes in the 30-40 kt range over much of

the area.



Farther east/southeast, cool/stable air north of a damming/preceding

frontal zone across VA and the Delmarva should limit the northern

end of severe potential.  Destabilization and available moisture

will be substantially limited today in the nominal warm sector,

between the damming front and a great deal of MCS/outflow activity

to the south over the Carolinas/GA.  Therefore, while thunderstorms

are possible this afternoon and deep shear may be adequate for a few

organized cells, severe potential appears isolated.



..Smith/Jewell.. 05/09/2024



$$