MESOSCALE PRECIPITATION DISCUSSION 0235
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
132 PM EDT FRI MAY 19 2017

AREAS AFFECTED......NORTH CENTRAL TEXAS TO RED RIVER VALLEY...

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 191732Z - 192332Z

SUMMARY...THE THREAT OF TRAINING SHOWERS/THUNDERSTORMS ALONG A LOW
LEVEL BOUNDARY MAY RESULT IN A FLASH FLOOD THREAT THIS AFTERNOON
IN NORTH CENTRAL TEXAS TO SOUTHEAST OK.

DISCUSSION...SHOWERS AND THUNDERSTORMS CONTINUE IN THE VICINITY OF
A LOW LEVEL BAROCLINIC ZONE WITH DEWPOINTS IN THE LOWER 70S
ADVANCING TOWARDS THE BAND FROM CENTRAL TEXAS. 

CLUSTERS OF SHOWERS/STORMS ARE EXPECTED TO
PERSIST AS COUPLED UPPER DIVERGENCE/LOWER CONVERGENCE COUPLETS
OCCUR UNDER DIFLUENT FLOW ALOFT DOWNSTREAM FROM AN UPPER JET
MAXIMA OVER NEW MEXICO AND SOUTHWEST TEXAS. THE HIGH RESOLUTION
RAPID REFRESH RUNS CONTINUE SHOWING WELL DEFINED 850-700 MB
MOISTURE FLUXES INTO THE BAND.  THE CLUSTER CONTINUES TO BE
SUPPORTED BY
INSTABILITY...INCLUDED MIXED LAYER CAPE VALUES NEAR 2000
J/KG...EVEN HIGHER SOUTH OF THE BAND.

THE COMBINATION OF ESTIMATED PRECIPITABLE WATER VALUES NEAR 1.5
INCHES AND SURFACE DEWPOINTS CLIMBING TO NEAR 70 DEGREES PROVIDES
PLENTIFUL MOISTURE TO BE TAPPED BY THE CONTINUING UPPER LEVEL
DIVERGENCE..SO LOCALLY HEAVY RAIN WILL OCCUR.

DEEP LAYER MEAN WINDS ARE FORECAST TO BE SOUTHWEST....RESULTING IN
A NET NORTHEAST MOTION.  2-4 INCHES OF RAIN ARE EXPECTED WITHIN
THE BAND THROUGH 00Z.  THE POTENTIAL IS THERE FOR ISOLATED HIGHER
AMOUNTS THIS PERIOD...CONTINUING INTO LATER THIS EVENING. THESE
AMOUNTS ARE FORECAST BY
THE HIGH RES NSSL WRF...HIGH RES RAPID REFRESH (HRRR)...AND WRF
ARW THIS AFTERNOON AND EVENING. THESE RAINS COUPLED WITH LOCALIZED
TRAINING OF CELLS MAY CAUSE FLASH FLOODING AS A RESULT.

PETERSEN

ATTN...WFO...FWD...OUN...SJT...

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

LAT...LON   34959637 34649619 34059665 33349748 32789815
            32229871 31419967 31450043 32020027 32629991
            33499905 34079842 34589765 34829713