563
ACUS01 KWNS 291254
SWODY1
SPC AC 291252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Mon Apr 29 2024

Valid 291300Z - 301200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THROUGH LATE
AFTERNOON ACROSS THE LOWER MS VALLEY...SOUTH TX...AND SOUTHEAST
LOWER MI...

...SUMMARY...
Marginally severe wind gusts and hail will be possible today across
south Texas, the lower Mississippi Valley and southeast Lower
Michigan.

...Lower MS Valley/Gulf coast today...
A midlevel shortwave trough over northwest TX/western OK will
progress eastward to the lower MS Valley by early tonight.  This
wave is preceded by a large MCS now over southern LA and the
adjacent northwest Gulf of Mexico.  Outflow with this convection
will continue moving southeastward through day, with some additional
storm development possible into southeast LA/southern MS on the
eastern flank of the MCS today.  Surface heating in cloud breaks,
lingering midlevel lapse rates at or above 7 C/km, and
boundary-layer dewpoints of 68-72 F will contribute to moderate
buoyancy and the potential for strong updrafts along the leading
edge of the MCS.  Vertical shear will not be particularly strong,
but the stronger storms will be capable of producing isolated
downburst wind damage through this afternoon.

Farther north, the residual effects of prior and ongoing convection
will be reduced lapse rates and low-level moisture, which along with
lingering clouds will tend to limit buoyancy.  Thunderstorm
development will be still be possible this afternoon/evening from AR
into western TN/KY along and in advance of a weak surface front and
the midlevel trough approaching from OK.  However, severe storms are
not expected as a result of both weak buoyancy and relatively weak
vertical shear.

...South TX this afternoon...
A weak front will drift southward into south TX by this afternoon,
providing a potential focus for isolated thunderstorm development.
Rich moisture, steep midlevel lapse rates and modest deep-layer
vertical shear (straight hodographs) could support isolated large
hail/wind damage if storms do form.

...Lower MI this afternoon...
A midlevel trough will continue northeastward from the upper MS
Valley to the upper Great Lakes, while an associated/weak surface
cyclone and cold front move across WI/MI this afternoon through
tonight.  Southeast Lower MI will be located within the warm sector
and could have an opportunity for some surface heating/
destabilization just east of the weakening rain band from IN into
western Lower MI.  MLCAPE up to 500 J/kg, steepening low-level lapse
rates and 50 kt midlevel flow support a low-end threat for wind
damage this afternoon.

..Thompson/Leitman.. 04/29/2024

$$