MESOSCALE PRECIPITATION DISCUSSION 0462
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
610 AM EDT FRI AUG 21 2015
 
AREAS AFFECTED...CNTRL AND UPPER TEXAS COAST 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 211007Z - 211400Z
 
SUMMARY...LOCALLY HEAVY RAINFALL RATES WILL BE POSSIBLE THROUGH
14Z ACROSS PARTS OF THE CNTRL AND UPPER TEXAS COAST AS A WEAK
MESOLOW MOVES INLAND. FLASH FLOODING IS A CONCERN GIVEN HEAVY
RAINFALL WHICH OCCURRED ON THURSDAY. 

DISCUSSION...0930Z ANALYSIS SHOWED A MESOLOW JUST OFFSHORE CORPUS
CHRISTI BAY...TRACKING NORTH WITH INFRARED SATELLITE SHOWING THE
BEST CLOUD TOP COOLING OCCURRING SOUTHEAST OF THE CIRCULATION
CENTER...OVER GULF WATERS. REGIONAL RADAR IMAGERY DEPICTED A
NORTH-SOUTH AXIS OF TRAINING HEAVY RAIN JUST SOUTH OF THE
MESOLOW...CO-LOCATED WITHIN 15-20 KTS OF SRLY 850 MB FLOW PER KBRO
AND KCRP VAD WIND PLOTS. THIS CONVECTION WAS OCCURRING WITHIN
AMPLE INSTABILITY LOCATED OFFSHORE AS DEPICTED IN LATEST SPC
MESOANALYSIS WHILE RAINFALL INTENSITY INLAND OVER ARANSAS AND
CALHOUN COUNTIES WAS DIMINISHED. RECENT GPS PRECIPITABLE WATER
VALUES RANGED BETWEEN 2.1 AND 2.3 INCHES BETWEEN CORPUS CHRISTI
BAY AND GALVESTON BAY. 

AS THE MESOLOW NEAR CORPUS CHRISTI CONTINUES NORTH THIS
MORNING...CONVECTION IS EXPECTED TO INCREASE INLAND PAST 1100 OR
1200 UTC WITH ONSET OF DAYTIME HEATING...ALONG THE IMMEDIATE
COASTAL COUNTIES...AS AN OFFSHORE TROUGH AXIS WEAKENS OR SHIFTS
INLAND. THE LATEST AVAILABLE HI-RES MODELS DO NOT HAVE THE
OFFSHORE CONVECTION SAMPLED WELL...SO CONFIDENCE IS MUCH LOWER
THAN USUAL. HOWEVER...SUFFICIENT SIGNALS SEEM TO BE PRESENT IN
OBSERVATIONAL IMAGERY TO SUGGEST A LOW END FLASH FLOOD
THREAT...MAINLY FOCUSED ALONG THE FIRST AND SECOND ROW OF COUNTIES
BETWEEN SAN ANTONIO BAY AND BEAUMONT TEXAS.

OTTO

ATTN...WFO...CRP...HGX...LCH...

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

LAT...LON   30009437 29659414 29029466 28319609 27989692 
            28379711 28999683 29499612 29879534