ACUS01 KWNS 121952
SWODY1
SPC AC 121950

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0250 PM CDT Sun May 12 2024

Valid 122000Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
FROM SOUTHEAST TX TO SOUTHWEST MS...AND THIS EVENING ACROSS THE
EDWARDS PLATEAU OF TX...AS WELL AS NORTHEAST WI/SOUTHERN U.P. OF
MI...

...SUMMARY...
Large hail, locally damaging winds, and a couple tornadoes are
possible from southeast Texas into Louisiana and southwest
Mississippi through tonight.  Isolated very large hail will be
possible this evening across the Edwards Plateau of Texas.  Damaging
winds and large hail will be possible this evening across northeast
Wisconsin and the southern Upper Peninsula of Michigan.

...20z Update...

No changes were needed at 20z to the existing outlook.

...East TX/LA/MS...
Scattered severe thunderstorm activity is ongoing along and south of
the warm front into eastern Texas and Louisiana, with hail reports
up to 2 inches. Additional thunderstorm activity is expected to
develop through the late afternoon/evening with further severe
potential continuing late into the period. See MCD#759 for more
information.

...Edwards Plateau in TX this afternoon/evening...
Air mass recovery has been slow across the region near the Edwards
Plateau in Texas with persistent mid-level cloud cover limiting
daytime heating. CAM solutions are spread on potential for a
supercell or two to develop through the evening. RAP forecast
soundings indicate a conditional threat for very large hail and a
tornado, given strong deep layer shear and elongated hodographs with
increasing mid-level flow. Given the conditional potential for large
hail, the Slight Risk was maintained with this outlook.

A Slight Risk continues across WI/MI this afternoon through the
evening. High-based storms with damaging wind and hail will be
possible.

..Thornton/Jewell.. 05/12/2024

.PREV DISCUSSION... /ISSUED 1127 AM CDT Sun May 12 2024/

...East TX/LA/MS through early Monday morning...
A midlevel trough will move slowly eastward from CO/NM to
KS/OK/northwest TX through tonight, with only a weak surface
reflection of the midlevel trough across OK/KS. Farther south, a
warm front will make slow progress northward into southeast TX and
southern LA, though the position of the surface front will be
modulated by the effects of ongoing/slightly elevated convection
moving toward east TX.  This early convection will pose a continued
threat for occasional large hail and damaging outflow gusts into
early afternoon.

By mid afternoon and through late evening, the potential for
near-surface-based storms will increase along the warm front in
southeast TX/southwest LA where low-level shear/hodograph curvature
will be sufficient for supercells with a few tornadoes.  There is
some potential for a larger storm cluster to evolve from the warm
frontal storms by this evening, and storms could persist through the
overnight/early morning hours as far east as MS.

...Edwards Plateau in TX this afternoon/evening...
A couple of supercells will be possible later this afternoon/evening
near the front/dryline triple point roughly in the vicinity of San
Angelo.  MLCAPE > 2500 J/kg, steep midlevel lapse rates and long
hodographs will favor isolated very large hail (up to 2.5 inches in
diameter) as the main threat for a few hours into this evening.

...WI/MI this afternoon through early tonight...
The southeast fringe of the midlevel height falls and a surface cold
front will help focus thunderstorm development after about 21z, and
storms will spread southeastward through late evening/early
overnight.  Afternoon surface temperatures of 75-80 F and dewpoints
of 45-52 F in WI will drive steep low-level lapse rates and SBCAPE
of 500-1000 J/kg, which combined with modest deep-layer shear will
support the potential for high-based storms capable of producing
damaging winds of 60-70 mph and large hail of 1-1.5 inches in
diameter.  The convection will likely become elevated over Lower MI
by late evening/early tonight with some continued potential for
isolated large hail.

...Extreme southwest KS/southeast CO/OK Panhandle this afternoon...
Cloud breaks will allow surface heating and steepening low-level
lapse rates in the vicinity of a weak surface cyclone across extreme
southeast CO.  Deep-layer shear will be weak close to the midlevel
trough, but sufficient buoyancy/minimal inhibition and a vertical
vorticity source will support the potential for a few landspouts
mid-late afternoon.

$$
--- SBBSecho 3.20-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)