SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1138 AM CST Mon Jan 23 2023
Valid 241200Z - 251200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER THE MIDDLE
AND UPPER TEXAS COAST...AND FROM SOUTHERN LOUISIANA EASTWARD INTO
THE FLORIDA PANHANDLE...
...SUMMARY...
Severe thunderstorms are expected from the middle to upper Texas
Coast Tuesday afternoon, spreading into parts of southeastern
Louisiana and across coastal Mississippi, Alabama and the western
Florida Panhandle by Wednesday morning. Damaging winds and several
tornadoes are anticipated, with a conditional threat of a strong
tornado.
...Synopsis...
A deep upper low will move eastward from northern TX during the day
into the middle MS Valley by 12Z Wed. Leading this trough will be a
80-100 midlevel jet streak, with extreme 70+ kt 850 mb wind fields
translating east across the Gulf Coast states. At the surface, low
pressure will develop across southeast TX during the day, pivoting
northeast across LA and AR overnight. Meanwhile, a warm front will
extend east from the low, with mid 60s F dewpoints south of the
Houston area. This front will lift north of I-10 in LA after 00Z,
with mid to upper 60s F dewpoints eventually overspreading southeast
LA, and the coastal counties of MS, AL, and the western FL
Panhandle. A cold front will surge east across the northern Gulf
coast states immediately behind the warm front, resulting in a
limited warm sector.
...Middle and upper TX Coast - Daytime...
Rain and elevated storms will rapidly expand across central TX
during the day, with intensification occurring over south-central
into southeast TX as the warm sector develops northward. Storms are
forecast to become severe after 18Z along the cold front, and warm
front intersection where a surface low will develop. Here, dewpoints
are expected to be sufficient for surface-based storm inflow, with
MLCAPE to around 1000 J/kg. Shear profiles will be extreme, with
effective SRH over 500 m2/s2 and near 800 m2/s2 along the warm front
south of the Houston area. Supercells will be likely along the
developing line of storms near the cold front, and a favored area
for strong tornadoes will be as this lift intersects the warm front.
Heating is unlikely given the early moisture return and saturated
boundary layer, but the extreme shear warrants an outlook for
isolated strong tornadoes.
...Southern LA...MS...AL...FL Panhandle - Evening and Overnight...
A squall line is forecast to move across the Sabine River around
00Z, progressing across LA and into MS through 06Z. The degree of
severe risk will be closely tied to boundary-layer destabilization,
and southern parts of the line across southern LA may weaken with
time. Damaging winds appear most likely with much of the line, but
southern parts of the line will have better access to more unstable
air, with conditional tornado risk. SBCAPE will eventually exceed
500 J/kg, with extreme SRH of 400-800 m2/s2 coincident with positive
SBCAPE.
Additional supercells with tornado threat may develop after 09Z near
the warm front/ahead of the cold front from southern AL into the FL
Panhandle, with damaging winds and a few tornadoes possible with
MLCAPE > 500 J/kg moving onshore.
..Jewell.. 01/23/2023
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