MESOSCALE PRECIPITATION DISCUSSION 0240
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
155 PM EDT THU MAY 26 2016
 
AREAS AFFECTED...SOUTHEAST/SOUTH-CENTRAL TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 261753Z - 262353Z
 
SUMMARY...A CONVECTIVE COMPLEX WITH CLOUD TOPS COLDER THAN -80C
CONTINUES TO EXPAND IN COVERAGE IN SOUTHEAST TX.  HOURLY RAIN
RATES UP TO 2.5" COULD LEAD TO FLASH FLOODING, PARTICULARLY IN
URBAN AREAS.

DISCUSSION...A MATURING MESOSCALE CONVECTIVE COMPLEX COVERS
SOUTHEAST TX, SURROUNDED ON ITS WESTERN SIDE BY A LENGTHENING ARC
CLOUD STRETCHING FROM SOUTHERN OK TO THE TX GULF COAST.  THE
OUTFLOW HAS REINFORCED THE DEW POINT GRADIENT EXTENDING FROM
AUSTIN THROUGH THE PINEY WOODS OF EASTERN TX.  PRECIPITABLE WATER
VALUES ARE 1.8-2.2" PER GPS INFORMATION.  INFLOW AT 850 HPA INTO
THE COMPLEX CONTINUES TO BE OUT OF THE SOUTH-SOUTHWEST AT 30 KTS
PER VAD WIND PROFILES.  MLCAPES TO ITS SOUTHWEST REMAIN 2000-3000
J/KG.

THERE HAVE BEEN SOME RECENT INDICATION OF THUNDERSTORMS EXTENDING
FARTHER WESTWARD TOWARDS CENTRAL TX ON ITS SOUTHWEST FLANK ON
RADAR IMAGERY -- RAP FORECAST FIELDS INDICATE SOME BACKING OF THE
LOW-LEVEL FLOW COULD ALLOW THIS WESTWARD BACKBUILDING ALONG/NEAR
THE CAP EDGE AND THERMAL BOUNDARY, WHICH IS ROUGHLY BETWEEN AUSTIN
AND JUNCTION.  AN UPSTREAM SHORTWAVE IN WESTERN TX COULD ALSO BE
AIDING THIS NEW MORE WESTERLY DEVELOPMENT.  THE COMPLEX HAS SLOWED
AS IT HAS ENTERED THE MOISTURE PLUME AND IT MAY HAVE TO WAIT FOR
THE WEST TX SHORTWAVE TO BOOT IT OUT IN 4-6 HOURS.  THE MESOSCALE
GUIDANCE SHOWS A UNIFIED, STRONG SIGNAL FOR 4-6" OF RAIN OVER THE
NEXT SEVERAL HOURS, WHICH COULD FALL QUICKLY.  AVAILABLE MOISTURE
SUPPORTS HOURLY RAIN RATES UP TO 2.5".  FLASH FLOODING IS
POSSIBLE, PARTICULARLY WITHIN URBAN AREAS SUCH AS HOUSTON,
BEAUMONT/PORT ARTHUR, AND POTENTIALLY AUSTIN/SAN ANTONIO.

ROTH

ATTN...WFO...CRP...EWX...FWD...HGX...LCH...SHV...

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

LAT...LON   31439423 31219359 30549354 29859370 29489407 
            29039499 28979588 29049808 29539927 30259852 
            30619781 30979705 31359571