Graphic for MPD #0087
Mesoscale Precipitation Discussion 0087
NWS Weather Prediction Center College Park MD
304 AM EST Fri Mar 08 2024

Areas affected...Southern Edwards Plateau into Western Hill
Country of Central Texas...

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

Valid 080805Z - 081130Z

SUMMARY...Very short window for initially stationary thunderstorms
to produce 2-3" totals in 1-2 hours before generating cold pools
for sufficient cell motions to reduce rainfall totals and
therefore flash flooding risk

DISCUSSION...Solid 15-20kt surface to boundary layer return flow
up the Rio Grande Valley intersects the dry line in proximity to
6R6 and OZA in the lower Pecos Valley.  Low to mid 60s Tds and
modestly mixed mid-level profiles support a pocket of enhanced
instability with SBCAPEs of 2000-2500 J/kg.  GOES-E and Regional
RADARs depict a solid line of development at the tail end of the
mid-level forcing/trof axis and surface dry-line - convergence
axis.  Given mid 60s Tds and CIRA LPW denoting localized PW
maxima/tight gradient through the 3 lower layers (sfc-850;
850-700; and 700-500), solid moisture loading to the profiles
should allow for solid rainfall production along with some loss to
hail.  03z HRRR 15-min rainfall totals suggest .5-.75" totals
given both updraft stregth and flux into the column.

Additionally,  the strong sfc to boundary layer moisture
convergence is aligned favorably low level to mid-level
orientation to the deep layer flow (generally parallel) supports a
line of thunderstorms that will have a short-term period of
training.  As such a few hours of very intense rainfall rates
(1.5-2"/hr) may result in a few localized spots of 2-3" totals,
potentially exceeding 1-3hr FFG values in the area.  However,
mid-level dry air will mix and aid in cold pool development in
about an additional hour or two to finally promote forward
(eastward propagation) of the delevloping line.  Still, given the
intensity of the cores and potential for training, a spot or two
of flash flooding is considered possible over the next 2-3 hours.

Gallina

ATTN...WFO...EWX...SJT...

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

LAT...LON   31109933 30949847 30579837 30199862 29879946
            29710030 29690102 29820145 30250170 30770107
           
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Last Updated: 304 AM EST Fri Mar 08 2024