Mesoscale Precipitation Discussion 1082
NWS Weather Prediction Center College Park MD
1231 PM EDT Wed Oct 13 2021
Areas affected...southwest into west-central Texas
Concerning...Heavy rainfall...Flash flooding possible
Valid 131631Z - 132231Z
Summary...Onset of a long-duration flash flood threat is underway
across the discussion area.
Discussion...Latest observations and objective analyses indicate a
nearly surface boundary extending from near 6R6 (near the Big Bend
region of Texas) east-northeastward to near the Dallas/Fort Worth
Metro area. Along and southeast of the front, abundantly moist
and unstable air was supporting scattered showers and
thunderstorms near the front that were increasing in coverage and
intensity this morning. Flow aloft was southwesterly - generally
parallel to the front - which was already allowing for some
training especially near the convective band about 70 WSW of SJT.
Areas of 1"/hr rates were already noted, which is not particularly
surprising given 1.5-1.9 inch PW values along and ahead of the
front.
Over the next 6 hours (and potentially beyond), models depict a
gradual expansion of convective coverage primarily due to weak
confluence/convergence along and ahead of the front. The approach
of moisture/lift associated with Tropical Cyclone Pam along the
western coast of Mexico will also contribute to expanded
convective coverage over time as well. FFG thresholds are
generally in the 2-3"/hr range across most of the discussion area
(slightly lower near the Austin/San Antonio corridor), suggesting
that the greatest flash flood threat will be tied to areas that
can experience training and/or persistence of heavy rainfall in
the near term.
Cook
ATTN...WFO...EWX...FWD...MAF...SJT...
ATTN...RFC...WGRFC...NWC...
LAT...LON 32689805 32479765 31719781 30789875 29679955
29130038 29300089 29560173 29570234 29690269
30450231 31190151 32489919