SPC Mar 12, 2025 0600 UTC Day 1 Convective Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1254 AM CDT Wed Mar 12 2025

Valid 121200Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER NORTHEAST
TEXAS...SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS...AND NORTHERN
LOUISIANA...

...SUMMARY...
A few severe thunderstorms producing large hail and localized wind
damage are possible from northern and eastern Texas into southeast
Oklahoma across southern Arkansas and northern Louisiana late this
afternoon and evening. Isolated severe activity may persist as far
east as western Mississippi by Thursday morning.

...Synopsis...
An upper-level low will eject across the southern Plains today with
a belt of strong mid-level westerly flow across Texas and Louisiana.
In response, a surface low will develop across western Texas and
Oklahoma with increasing southerly flow and moisture return across
Texas into Oklahoma and into the lower Mississippi Valley ahead of
the dryline/front.

Initially, low levels will remain strongly capped during the
day/early afternoon, thereby inhibiting convection. As the mid-level
low approaches, cooling aloft will steepen lapse rates and lead to
increasing instability. As forcing overspreads the dryline/cold
front, isolated to scattered thunderstorm development will be
possible across portions of southeastern Oklahoma, southern
Arkansas, and northern Louisiana with the potential for damaging
winds and large hail.

...Northeast TX...Southeast OK...Southern AR...Northern LA...
As the surface low tracks eastward, upper-level flow will overspread
the dryline/cold front across southeastern Oklahoma into northeast
Texas. Models are in agreement that dew points in the upper 50s to
60s will reach the Red River by around 00z. Sounding profiles
indicate that a strong capping inversion will remain in place for
most of the morning and afternoon, with potential for strong daytime
heating and mixing that may lower dew points. Regardless, it appears
that MUCAPE aloft around 1000-1500 J/kg will develop above this, and
that convective development should occur by the later
afternoon/evening. Though there is some uncertainty on coverage,
deep layer shear around 45-55 kts and steep lapse rates would
support organized supercells with potential for very large hail and
damaging winds. The large hail threat remains most likely where
supercells can develop from northeast Texas into southeastern
Oklahoma, where forcing will intersect the dryline/cold front. This
is further supported by signal for development in most CAM guidance
as well as ensemble guidance from HREF, which develops UH tracks
across this region and has signal in paint balls for >40 dbz
development.

As convection continues to develop and move eastward with time, some
upscale growth will be possible. The threat will likely transition
to primarily damaging wind into portions of southern Arkansas and
Mississippi before storms weaken in the less favorable air mass.

..Thornton/Goss/Squitieri.. 03/12/2025

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