SPC Dec 24, 2024 1300 UTC Day 1 Convective Outlook

SPC 1300Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0651 AM CST Tue Dec 24 2024

Valid 241300Z - 251200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
CENTRAL...EAST...AND SOUTHEAST TEXAS...

...SUMMARY...
Isolated to widely scattered strong to severe thunderstorms capable
of large hail and damaging gusts are possible late this afternoon
into the overnight.

...Central and eastern TX...
Water-vapor imagery early this morning shows an upper trough digging
southeastward over the southern High Plains.  This upper feature is
expected to reach eastern TX and the western Gulf of Mexico by early
Wednesday morning.  In the low levels, morning analysis indicates an
inverted trough extending from central TX northeastward into the
Arklatex.  A cold front over north TX extending southwestward into
west-central TX will gradually move southeastward during the period
and become a focus for showers/storms.  Southeasterly low-level flow
ahead of the front will maintain an adequately moist fetch from the
western Gulf (upper 50s to lower 60s dewpoints).  Some heating
during the day and mid-level cold-air advection will likely yield
moderate destabilization (750-1500 J/kg MLCAPE) from near I-20 in
northeast TX southwestward into the TX Triangle.  The relatively
cold mid levels will promote hail growth with the stronger updrafts
that maintain a cellular mode, but a transition to linear is
expected given the frontal forcing and modest high-level flow
promoting updraft seeding from adjacent storm activity by early
evening.  A locally higher risk for large hail may ultimately focus
near the I-35 corridor from San Antonio northward through Waco.  A
gradual emphasis towards damaging wind potential is expected during
the evening/overnight as storm coverage increases coincident with a
more pervasive linear mode.

Elsewhere, a progressive and powerful upper trough will move from
the eastern Pacific and into the UT/AZ vicinity by late tonight. 
Isolated low-topped thunderstorms may occur in association with cold
mid-level temperatures overspreading CA into the southern Great
Basin.  Scant instability will tend to limit storm vigor and overall
coverage of thunderstorm activity.

..Smith/Grams.. 12/24/2024

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