112
AWUS01 KWNH 042035
FFGMPD
TXZ000-NMZ000-050200-

Mesoscale Precipitation Discussion 0222
NWS Weather Prediction Center College Park MD
435 PM EDT Sat May 04 2024

Areas affected...western to central TX

Concerning...Heavy rainfall...Flash flooding likely

Valid 042032Z - 050200Z

Summary...Increasing thunderstorm coverage across western to
central TX will result in a likely threat of flash flooding
through the evening. Rainfall rates of 1-2 in/hr will be common
but localized rates of 2 to just over 3 inches per hour will also
be possible. Overlap of heavy rain with wet antecedent soils,
especially over sections of the Hill Country and central TX will
increase runoff potential.

Discussion...20Z radar imagery over West TX showed convective
initiation underway with cells off of the Davis Mountains and
surrounding terrain, as well as near the intersection of a dryline
and stationary front, with a developing supercell 15-20 miles
northwest of Wink, TX. Visible satellite imagery showed weaker
convection just north of a remnant outflow boundary extending east
from Wink, to 30 miles north of San Angelo. The environment near
and south of the outflow boundary contained 2000 to 3000+ J/kg
MLCAPE and 1 to 1.5 inches of precipitable water (higher to east)
via the 20Z SPC mesoanalysis, with decreasing CIN over the past
few hours.

As increasing ascent overspreads the area through 00Z, ahead of a
mid to upper-level trough over AZ/NM and associated left exit
region of a 110-120 kt jet max over northern Mexico, thunderstorm
coverage is expected to increase across the Permian Basin within
the warm sector. Low level easterly flow within the cool sector
will promote upslope enhancement to thunderstorms to the immediate
north of outflow. While uncertain, convection may develop farther
east over the Hill Country into the I-35 corridor toward 00Z as
well but low level convergence is less defined with eastern extent
and thick cloud cover is limiting surface heating, with a capping
inversion likely present between 850-700 mb as seen on 12/18Z MAF
and 12Z DRT sounding data.

Individual cell motions should be somewhat progressive from the SW
at 10-20 kt but more organized supercells will be slower and more
W to E in movement. Parallel movement to existing boundaries will
support training with some upstream development and potential for
rainfall rates in excess of 2 in/hr, but a general movement of
thunderstorms toward the east is expected through 02Z, out ahead
of the approaching upper trough. Areas of flash flooding are
expected to become likely thorough the evening as thunderstorm
coverage increases.

Otto

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

ATTN...WFO...EWX...FWD...MAF...SJT...

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

LAT...LON   32650273 32530084 32319971 32069854 31879724
            30869684 29989833 30330193 30760358 32110387