581
AWUS01 KWNH 290117
FFGMPD
TXZ000-290600-

Mesoscale Precipitation Discussion 0339
NWS Weather Prediction Center College Park MD
916 PM EDT Tue May 28 2024

Areas affected...Rolling Plains into Big Country of Northwest
Texas...

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

Valid 290115Z - 290600Z

SUMMARY...Cell mergers and training along with ample moisture flux
for up to 2"/hr rates and 2-3+" may pose localized flash flooding
through early overnight period.

DISCUSSION...RAP analysis and 01z surface map suggest a weak FGEN
boundary/pressure trough across Northwest Texas that has a pool of
enhanced instability along it, with CAPE over 1500 J/kg.   Earlier
cluster of thunderstorms has evolved into a fast moving outflow
boundary across western OK before angling back southwestward
across the Rolling Plains into the Big Country intersecting with
the W-E developing boundary and instability pool.  As such, recent
convective development has sprouted with overshooting tops rapidly
cooling and congealing to a broad line of sub -60C cloud tops in
10.3um GOES-E IR.  RADAR notes generally chaotic cell motions
given broad deep layer confluence zone per VWP network and RAP
analysis fields.  Tds in the low 60s with LPW depicting an
enhanced axis of moisture from sfc to 700 across south-east TX
toward this area allowing for total PWAT values to be in the 1.4"
range per GPS network.  Given deep layer flux convergence, and
updraft strength has supported increased rainfall rates up to
1.5-1.75".  Cell mergers and slow motions may allow for some
localized 2-3" totals in 1-2hrs; and while the area has been
recently dry, this is still in the range of 1-3hr FFG values.

Hi-Res CAMs have performed poorly this evening with the overall
evolution. However, recent WoFS runs (a majority of members) have
maintained some these cells for a few hours likely feeding off the
local instability maxima noted.  As such, mean rainfall totals
suggest a more reasonable 2-3" totals, though hint at localized
values of 3- 4" when looking at 90th percentile of the last few
cycles.  This provides some confidence in reaching totals that
would result in localized flash flooding.  As such, flash flooding
is considered possible through the early overnight period before
the cluster moves further east into a more stable environment.

Gallina

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

ATTN...WFO...FWD...LUB...MAF...SJT...

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

LAT...LON   33610107 33380001 33259922 33049843 32519810
            31899846 31809917 32060023 32630132 33310165