Subj : DAY3SVR: Nws Storm Prediction Center Norman Ok
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Tue Apr 18 2023 07:30:55

ACUS03 KWNS 180730
SWODY3
SPC AC 180729

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0229 AM CDT Tue Apr 18 2023

Valid 201200Z - 211200Z

....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF THE
MID MISSISSIPPI VALLEY SOUTHWESTWARD INTO THE ARK-LA-TEX AND
SOUTHERN PLAINS...

....SUMMARY...
Severe thunderstorms associated with wind damage and isolated large
hail will be possible across parts of mid Mississippi Valley
southwestward into the Ark-La-Tex and southern Plains Thursday
afternoon and evening.

....Mid Mississippi Valley/Ark-La-Tex/Southern Plains...
An upper-level trough, along with an associated 60 to 80 knot
mid-level jet, will move through the Great Plains on Thursday. At
the surface, a cold front will move eastward through the lower
Missouri Valley, and southeastward through southern Plains. Ahead of
the front, surface dewpoints are expected to range from near 60 F in
east-central Missouri to the upper 60s F in parts of east and
northeast Texas. As temperatures warm during the day, an axis of
instability will develop ahead of the front. Convection is expected
to first initiate in the mid Mississippi Valley, aided by
large-scale ascent ahead of the upper-level trough and an associated
70 to 80 knot mid-level jet. Several storm clusters are expected to
form and persist from late afternoon into the evening. Further to
the southwest from Arkansas into east Texas, moderate instability
will be in place by afternoon. As low-level convergence increases
along and ahead of the front, scattered thunderstorms are expected
to develop during the afternoon. Several clusters of organized
storms are likely during the late afternoon and evening.

NAM forecast soundings along the instability axis from southeast
Missouri into northeast Texas around 21Z show a favorable
environment for severe storms. MLCAPE is forecast to peak around
1500 J/kg in southeast Missouri to near 3000 J/kg in parts of the
Ark-La-Tex. 0-6 km shear is forecast to be from 35 to 45 knots,
suggesting supercells will be possible with cells that remain
discrete. Supercells will have a threat for large hail and wind
damage. However, winds are forecast to be somewhat veered ahead of
the front, which will likely tend to favor a linear convective mode.
If this occurs, then wind damage would be possible, especially along
the leading edge of the faster-moving line segments. Due the
stronger instability across east Texas and the Ark-La-Tex, the
severe threat is expected to persist longer, with an isolated severe
threat potentially continuing into the early overnight period.

...Broyles.. 04/18/2023

$$

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