MESOSCALE PRECIPITATION DISCUSSION 0192
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
900 PM EDT WED MAY 23 2018

AREAS AFFECTED...WEST TEXAS

CONCERNING...HEAVY RAINFALL

VALID 240100Z - 240500Z

SUMMARY...SLOW CELL MOTIONS AND HIGH RATES CONTINUE TO POSE
POSSIBLE FLASH FLOOD RISK THROUGH 05Z.

DISCUSSION...GOES-16 SUITE OF 1-MINUTE MESO SECTOR IMAGERY
CONTINUES TO SHOW NUMEROUS CONVECTIVE DEVELOPMENT AS WELL AS
MAINTENANCE OF OVERSHOOTING TOPS ACROSS THE SOUTHERN BIG BEND AND
TRANS PECOS REGION OF WEST TEXAS. WHILE DRY LINE CONTINUES TO
RETROGRADE FURTHER FROM ACTIVE CELLS THE LOW LEVEL WIND
ENVIRONMENT REMAINS STRONG WITH EASTERLY INFLOW PROVIDING AMPLE
MOISTURE FLUX ON 25KTS OF ESE WINDS AND LOW 60S TDS.  WHILE 00Z
SOUNDINGS FROM DRT AND MAF INDICATE GROWING INVERTED 'V' BOUNDARY
LAYER...TPWS TO 1" AND STRONG CONVERGENCE ARE MASS PILING WATER
VAPOR TO INCREASE RAIN GENERATION.  THREE WV CHANNEL SUITE ALSO
DENOTES FAVORABLE DIFFLUENT UPPER LEVEL PATTERN ACROSS THE REGION
AIDING STRONGER UPDRAFTS MAINTAINED ON 2000-2500 J/KG CAPES IN THE
REGION PER RAP ANALYSIS.  WHILE CAP STRENGTH APPEARS TO BE
INCREASING...ONGOING CONVECTION WILL HELP WITH CONVERGENCE ALONG
FORWARD OUTFLOW BOUNDARIES TO MAINTAIN THE CONVECTION. 
ADDITIONALLY...LLJ WILL BE STEADILY INCREASING OVER THE NEXT HOUR
OR SO TO SUPPORT FLUX.  HOWEVER...VEERING LLJ TOWARD 03-04Z IS
EXPECTED TO REDUCE THE FLUX/CONVERGENCE AND THEREFORE LEAD TO
REDUCTION OF RAINFALL AND THE FLASH FLOOD THREAT.

STILL THIS LEAVES A WINDOW OF 2-3 HOURS WITH CELLS SLOWLY MARCHING
EASTWARD...ESPECIALLY THOSE SUCH AS OVER FAR SOUTHERN BREWSTER
COUNTY THAT HAVE NOT ESTABLISHED MUCH OF ANY COLD POOLS.  RAIN
RATES OF 1.5"/HR ARE POSSIBLE WITH 3" TOTALS NOT OUT OF THE
QUESTION SUGGESTING FF RISK REMAINS POSSIBLE THROUGH 05Z.   

GALLINA

ATTN...WFO...MAF...SJT...

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

LAT...LON   31630276 31520210 30930185 30260178 29760179
            29740225 29530267 29150284 28900304 29020330
            29120358 29630385 30050395 30770364 31380324