MESOSCALE PRECIPITATION DISCUSSION 0168
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
225 AM EDT MON MAY 02 2016
 
AREAS AFFECTED...SERN TX...WRN/CNTRL LA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 020624Z - 021215Z
 
SUMMARY...THUNDERSTORMS ARE EXPECTED TO EXPAND ACROSS AN AREA FROM
SOUTHEASTERN TEXAS INTO WESTERN/CENTRAL LOUISIANA OVER THE NEXT
FEW HOURS. FLASH FLOODING IS LIKELY.

DISCUSSION...AN AXIS OF MOISTURE AND INSTABILITY CURRENTLY EXTENDS
FROM THE WESTERN GULF OF MEXICO NORTHWARD INTO SOUTHEASTERN TEXAS.
THE ATMOSPHERE IS WEAKLY CAPPED ACROSS THE OUTLINED AREA...BUT
ALREADY SEEING THE DEVELOPMENT OF NEW CONVECTION AS A WEAK
MID/UPPER-LEVEL SHORTWAVE MOVES EASTWARD ACROSS SOUTH TEXAS.
MID-LEVEL LAPSE RATES ARE STEEPENING SLIGHTLY IN ASSOCIATION WITH
THIS WAVE PER LATEST SPC MESOANALYSIS. THE ADDITIONAL SUPPORT
PROVIDED BY A STATIONARY SURFACE FRONT AS WELL AS ANOTHER BOUNDARY
ALONG THE COAST (LIKELY ORIGINATED FROM EARLY CONVECTION OVER THE
WATER) SHOULD ASSIST IN CONVECTIVE DEVELOPMENT OVER THE NEXT FEW
HOURS. ADDITIONALLY...IMPROVING UPPER-LEVEL DIFFLUENT FLOW THRU
12Z PER 00Z GLOBAL MODELS SHOULD ALLOW FOR EVACUATION OF AIR ALOFT
AND MAINTENANCE OF DEEP CONVECTION ONCE IT DEVELOPS.

HI-RES MODELS SHOW SOME CONSENSUS AMONG THE ARW, NMM, AND
EXPERIMENTAL HRRR THAT CONVECTION SHOULD CONTINUE TO EXPAND AND
ORGANIZE THROUGH 09-10Z. WHILE LOW/MID-LEVEL WIND FIELDS GENERALLY
FAVOR FORWARD PROPAGATING CONVECTION...THE INTERSECTION OF THE
BEST MOIST/UNSTABLE LOW-LEVEL INFLOW WITH THE COASTAL SURFACE
BOUNDARY COULD POTENTIALLY RESULT IN REPEAT CELL DEVELOPMENT OVER
COASTAL SOUTHEASTERN TEXAS FOR A PERIOD OF SEVERAL HOURS. THE ARW,
NMM, AND EXPERIMENTAL HRRR ALL INDICATE THE POTENTIAL FOR 2 TO 4
INCHES OF RAINFALL THROUGH 12Z ACROSS THE OUTLINED AREA, WITH
LOCALIZED HIGHER AMOUNTS. AN AREA OF REDUCED FLASH FLOOD GUIDANCE
ASSOCIATED WITH EARLIER RAINS FROM SOUTHEASTERN TEXAS INTO
SOUTHWESTERN LOUISIANA WILL RESULT IN AN INCREASED LIKELIHOOD OF
FLASH FLOODING ACROSS THAT AREA. FLASH FLOODING IS LIKELY.

RYAN

ATTN...WFO...HGX...LCH...SHV...

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

LAT...LON   31469254 31409229 31059195 30459187 29989200 
            29729232 29669271 29509391 29139457 29039539 
            29679526 30479487 31029430 31399353