397
AWUS01 KWNH 252017
FFGMPD
TXZ000-OKZ000-260215-

Mesoscale Precipitation Discussion 0323
NWS Weather Prediction Center College Park MD
416 PM EDT Sat May 25 2024

Areas affected...Portions of West-Central to Northern TX and
Southwest OK

Concerning...Heavy rainfall...Flash flooding possible

Valid 252015Z - 260215Z

SUMMARY...Slow-moving supercell thunderstorms will be capable of
producing locally very heavy rainfall totals and may pose a threat
for flash flooding going into the evening hours.

DISCUSSION...The latest GOES-E satellite imagery in conjunction
with regional dual-pol radar shows multiple supercell
thunderstorms developing over parts of west-central to northern TX
to the east of a well-defined dryline. The convection is
initiating in an uncapped and highly unstable airmass with strong
shear parameters in place that are conducive for supercell
thunderstorm development.

MLCAPE values of 3000 to 4000 J/kg are in place along with high
effective bulk shear values of locally over 60 kts. Meanwhile,
there is plenty of boundary layer moisture in  place across much
of central and northern TX with surface dewpoints as high as the
low to mid 70s.

This highly unstable and sheared environment will be in place
through the evening hours which coupled with the arrival of
stronger deeper layer ascent associated with an ejecting mid-level
trough from the central Rockies should favor some additional
development and expansion of supercell thunderstorm activity
across areas of central and northern TX and gradually into
southwest OK.

The last couple of runs of the experimental NSSL-WoFS and the 12Z
NSSL-MPAS guidance suggests pockets of slow-moving supercell
thunderstorm activity with some potential for cell-mergers and
localized repeating cell-activity. However, some of the potential
cell-merger activity will tend to also support some MCS
development/evolution with tendencies to perhaps be a bit more
progressive over time.

Aside from well-defined severe weather hazards, the rainfall rates
with these supercells will be quite high and capable of reaching
2.0 to 2.5 inches/hour, and with the aforementioned cell-motion
character, some spotty storm totals may reach 4 to 6 inches which
is suggested by the latest WoFS guidance.

While the overall coverage of convection may not necessarily be
that high, some isolated instances of flash flooding will be
possible where these supercell thunderstorms occur going into the
evening hours.

Orrison

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...AMA...FWD...LUB...OUN...SJT...

ATTN...RFC...ABRFC...WGRFC...NWC...

LAT...LON   35549931 35539788 34469672 32619696 31459810
            31469954 32180047 33260039 34230036 35059996