AWUS01 KWNH 192332
FFGMPD
TXZ000-200530-

Mesoscale Precipitation Discussion 0193
NWS Weather Prediction Center College Park MD
731 PM EDT Tue May 19 2026

Areas affected...portions of west and central Texas

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

Valid 192330Z - 200530Z

Summary...Slow-moving thunderstorms continue to produce high rain
rates - locally exceeding 2 inches/hr at times.  Flash flooding is
likely on at least a localized basis.

Discussion...In the last half hour, an east-west oriented band of
cellular convection has intensified rapidly along an axis from
near Big Lake, TX east to near Llano, with other scattered
convection northeast of that axis (west of Waco) and also just
north of the Big Bend area.  These storms were focusing along a
very slow-moving cold front in that vicinity.  Furthermore, very
strong mid-level lapse rates (exceeding 8C/km) and near 70F
dewpoints were contributing to 3000-4000 J/kg MLCAPE, further
supporting strong updrafts.  Weak steering flow was evident (only
20 knots or so at 500mb), enabling convection to exhibit slow and
at times erratic storm motions.  Moisture/instability profiles
were supporting local 2-2.5 inch/hr rain rates that were
approaching FFG.

Overall increasing convective trends are likely to continue amid a
subtle increase in low-level flow into the aforementioned front
through the evening hours.  Slow/erratic storm motions are likely
to continue with this activity, though upscale growth into a
convective complex appears probable as cold pools mature and
merge.  Models hint at additional convection emanating from
northern Mexican higher terrain that may also organize and merge
with pre-existing convection across the discussion area and pose a
flash flood risk.  Areas of 2-3 inch/hr rain rates are likely to
continue on at least a localized basis, posing a flash flood
threat especially in sensitive locales.  5 inch totals are also
possible.  This threat is likely to continue through 05Z/midnight
central time, and a gradual eastward and/or southeastward shift in
flash flood potential should materialize, though this evolution is
likely highly dependent on how quickly storms can grow upscale
during the evening. Locally significant impacts are possible in
sensitive/flood-prone areas.

Cook

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

ATTN...WFO...CRP...EWX...FWD...HGX...MAF...SJT...

ATTN...RFC...FWR...NWC...

LAT...LON   32169913 32029761 31589676 31199632 30409619 
            29599647 28919807 28499958 28340015 29080082 
            29660173 29460284 29830317 30790276 31910120