475
ACUS11 KWNS 280649
SWOMCD
SPC MCD 280649
OKZ000-TXZ000-280815-

Mesoscale Discussion 1031
NWS Storm Prediction Center Norman OK
0149 AM CDT Tue May 28 2024

Areas affected...the Red River Valley of OK/TX

Concerning...Severe Thunderstorm Watch 339...

Valid 280649Z - 280815Z

The severe weather threat for Severe Thunderstorm Watch 339
continues.

SUMMARY...Scattered large hail from several right and left-splitting
supercells will be the primary threat through the pre-dawn hours.
Later clustering will probably be necessary for an appreciable
severe wind threat.

DISCUSSION...Several right and left-splits have been noted over the
past hour, mainly across southwest and south-central OK into far
western north TX. Recent HRRR/RRFS runs remain completely off with
the early morning initiation of this activity. The 00Z ECMWF appears
to have adequately handled the ongoing evolution, with the 00Z
NAM-NEST and NSSL-ARW too slow but with the general idea of
low-level warm-advection driven storms persisting. With increasingly
large MUCAPE to the south of this activity, regenerative cells will
probably continue for the next few hours along the east periphery of
the low-level jet centered on west TX. Hail magnitudes should
occasionally peak around 2 inches per recent MESH estimates.

Farther north and northeast, from west-central to southeast OK, a
band of ACCAS is evident in radar/satellite imagery. Forecast
soundings suggest further low-level moistening may aid in this
activity deepening during the next few hours. But with weaker
MUCAPE, the severe hail threat here should be more marginal.

..Grams.. 05/28/2024

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FWD...OUN...

LAT...LON   34169966 34509976 34809946 35149898 35159785 34969691
            34779619 34399603 33989622 33709671 33649788 33749861
            33989936 34169966