Mesoscale Precipitation Discussion 0844
NWS Weather Prediction Center College Park MD
313 PM EDT Sat Sep 15 2018

Areas affected...Middle and Lower TX Coast...South TX to
South-Central TX

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

Valid 151915Z - 160100Z

Summary...Redeveloping convection may result in additional heavy
amounts and flash-flooding concerns.

Discussion...Latest mesoanalysis shows that the low-mid level
circulation over South Texas has drifted further northwest into
northern Webb County at 18 UTC.  Southerly flow east of the center
is tapping deeper moisture and greater instability, which along
with divergent flow aloft is supporting the redevelopment of
convection from the TX coast in the vicinity of Corpus Christi -
Rockport northward into South-Central TX.  KCRP radar rainfall
estimates have quickly increased over the last hour to 1.5-2 in/hr
within the heavier band near the coast.  As the low stalls over
the region, deep inflow will continue to support PWs of 2.25-2.5
inches with increasing instability spreading further to the north
within the highlighted region.  20-30 kt southerly low level
inflow, with weak flow aloft is expected to support
slow-moving/back-building convection.  Corfidi vectors from recent
runs of the RAP continue to show near zero magnitude within much
of the highlighted region through the afternoon.  For the 6-hr
period ending at 00 UTC, 40km neighborhood probabilities from the
12 UTC HREF are more than 50 percent for amounts greater than an
inch across much of the highlighted region.  This includes areas
recently impacted by heavy rains and where 3-hr flash flood
guidance values are an inch or less.

Pereira

ATTN...WFO...BRO...CRP...EWX...

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

LAT...LON   29249832 29109764 28409685 27599714 26649725
            26099752 26399833 26819845 27169845 28029827
            28689852