SPC AC 041731
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1131 AM CST Mon Mar 04 2024
Valid 051200Z - 061200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
EAST TEXAS/OKLAHOMA INTO THE LOWER MISSISSIPPI VALLEY...
Isolated strong to severe thunderstorms appear possible Tuesday
across parts of east Texas/Oklahoma into the lower Mississippi
Valley. Occasional large hail and damaging winds should be the main
A low-amplitude, broadly cyclonic, split-flow upper pattern will be
in place across the CONUS early Tuesday. A southern-stream shortwave
trough is forecast to begin the period over the Lower MS Valley
before then continuing eastward/east-northeastward across the
Southeast States throughout the day. This shortwave is expected to
end the period extended from the southern Appalachians into the
northeast Gulf of Mexico. Several shortwave troughs will likely be
embedded within the northern stream, including one wave which is
forecast to move from the Dakotas northeastward across the Upper
Midwest and into northwestern Ontario.
The surface pattern early Tuesday morning is expected to feature a
low over southern Lower MI A cold front will extend southwestward
from this low to another low over North TX. General expectation is
for this front to progress southeastward/eastward throughout the day
while becoming increasingly diffuse. Moderate low-level moisture
will be in place ahead of this front, with mid to upper 60s surface
dewpoints from east TX across the Lower MS Valley decreasing to the
upper 50s/low 60s across the Mid MS Valley. Showers and
thunderstorms will likely be ongoing early Tuesday along much of
this frontal zone, with at least isolated coverage anticipated along
and ahead of the front as it moves eastward throughout the day. The
strongest storms are anticipated from east TX/OK into the Lower MS
...East TX/OK into the Lower Mississippi Valley...
Showers and thunderstorms are expected to ongoing ahead of the cold
front from eastern OK into central TX early Tuesday morning.
Coverage and storm mode of these storms is uncertain, given the
uncertainties regarding storm development and evolution from late
Monday night/early Tuesday morning. Current expectation is for one
or more clusters to be ongoing, with the most probable location for
a cluster from central portions of East TX into the Arklatex.
Forecast soundings across the region show modest low-level stability
beneath an EML and attendant steep mid-level lapse rates and
relatively dry mid-level air. These thermodynamic profiles appear
supportive of strong downdraft production, which is confirmed with
many of the HREF members forecasting strong storm outflow. Some
organization on storm outflows may occur, but deep-layer vertical
shear is only expected to be around 30 kt, limiting the confidence
in upscale growth. This uncertainty regarding initiation and
subsequent convective evolution limits overall forecast confidence.
As such, will maintain Marginal probabilities for this outlook, but
a corridor of higher probabilities may be needed in subsequent
outlooks if convective evolution becomes more certain.
Evolution of this early-day activity will impact the potential for
redevelopment along the front during the afternoon and evening.
Guidance has trended towards redevelopment along the front from
east-central OK across north-central/northwest AR. Steep mid-level
lapse rates will remain in place, suggesting that there is a
conditional risk for hail and/or strong downdrafts with any storms
that do development. Limited vertical shear should keep storm
organization modest, tempering overall storm severity and duration.
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