SPC Feb 18, 2025 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook

Day 1 Convective Outlook RESENT 2
NWS Storm Prediction Center Norman OK
0341 PM CST Tue Feb 18 2025

Valid 182000Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
SOUTHEAST TEXAS INTO SOUTHERN LOUISIANA...

...SUMMARY...
Isolated severe thunderstorms remain possible this evening across
parts of southeast Texas, shifting across southern Louisiana
tonight. Hail should be the primary hazard, but a brief tornado and
occasional severe gusts may occur along the immediate Louisiana
Coast.

...20Z Update...
The previous forecast remains on track. Low-level warm-air and
moisture advection are already underway across coastal portions of
TX and LA, as indicated by 19Z mesoanalysis. Current thinking is
that the low-level warm-air/moisture advection will continue to
increase and boost elevated CAPE to 1000 J/kg along the coast with
the approach of a mid-level impulse currently situated over NM.
Elevated thunderstorms should develop later this evening. Mainly
hail is expected given elongated hodographs. However, if any
supercellular structure can materialize along the southeast LA coast
and become rooted in the boundary layer tonight, a damaging gust or
tornado cannot be ruled out.

..Squitieri.. 02/18/2025

.PREV DISCUSSION... /ISSUED 1029 AM CST Tue Feb 18 2025/

...Southeast Texas into Southern Louisiana...
Water-vapor imagery this morning shows a shortwave trough moving
into northern AZ from the Great Basin.  This upper feature will move
east-southeast during the period reaching northern LA/southern AR by
daybreak Wednesday.  Surface analysis this morning delineates an
arctic cold front from the Concho Valley northeastward into north
TX.  This boundary will continue to surge south-southeastward to the
TX coast tonight.  A modifying airmass over the northwest Gulf Basin
will aid in destabilization this afternoon/evening over southeast
TX.  Thunderstorms should eventually form by this evening across
parts of southeast TX as large-scale ascent increases.  Forecast
soundings continue to indicate this thunderstorm activity will
likely remain elevated with around 1000 J/kg MUCAPE.  This activity
will spread eastward across portions of southern LA late this
evening and overnight while posing mainly an isolated hail threat. 
The surface-based thunderstorm probabilities are greatest near the
south-central and southeast LA coast.  However, low-level lapse
rates in a deep/saturated environment will be modest, likely
limiting tornado potential.  Nonetheless, if a couple of storms can
become near-surface based in the coastal parishes, a risk for severe
gusts may accompany the stronger storms.

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