MESOSCALE PRECIPITATION DISCUSSION 0046
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
538 PM EDT FRI APR 17 2015
 
AREAS AFFECTED...CNTRL TO SERN TEXAS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 172138Z - 180238Z
 
SUMMARY...THE FLASH FLOOD THREAT IS INCREASING ACROSS PORTIONS OF
THE CNTRL AND ERN TEXAS COASTAL PRAIRIES WITH 3 HOURLY RAINFALL
RATES OF 3-4 INCHES EXPECTED THROUGH 02Z.

DISCUSSION...AT 21Z...A FORWARD PROPAGATING BOWING SEGMENT OF
CONVECTION OVER WILSON AND KARNES COUNTIES WAS OBSERVED TO BE
MOVING ENE AT AROUND 30 TO 35 KTS. IN ADDITION...RADAR/SATELLITE
SHOWED A THIN LINE OF SHOWERS ALONG A NWD DRIFTING CONVERGENCE
AXIS EXTENDING INTO THE GULF OF MEXICO TO JUST SOUTH OF MATAGORDA
BAY WITH ADDITIONAL...LESS ORGANIZED...CONVECTION TO THE SOUTHWEST
OF HOUSTON AND NORTH OF SAN ANTONIO. SURFACE BASED INSTABILITY IS
ESTIMATED TO BE ANYWHERE BETWEEN 1000-2500 J/KG ACROSS SOUTHEAST
TEXAS AND PRECIPITABLE WATER SOUTH OF A STATIONARY FRONT...LOCATED
ABOUT 100 MILES INLAND OF THE TEXAS COAST...WAS OBSERVED TO BE 1.8
INCHES PER SPECIAL 18Z SOUNDING AT CRP WHICH IS 2 TO 3 STANDARD
DEVIATIONS ABOVE THE NORM.

SRLY LOW LEVEL FLOW INTO SOUTHEAST TEXAS WILL CONTINUE TO ADVECT
DEEPER MOISTURE FROM THE SOUTH INTO THE THREAT AREA INTO THE
EVENING HOURS. IT IS EXPECTED...PER A CONSENSUS OF RECENT HI-RES
MODEL GUIDANCE...THAT THE BOWING SEGMENT WILL PRECEDE SCATTERED
SHOWERS DEVELOPING WITHIN THE WARM SECTOR...JUST AHEAD OF THE
BOWING SEGMENT...WITH THE OVERALL CLUSTER OF CONVECTION TO SPREAD
EASTWARD THROUGH 02Z...POSSIBLY IMPACTING PORTIONS OF
CHAMBERS...JEFFERSON...LIBERTY COUNTIES THAT RECEIVED 4-7 INCHES
OF RAIN OVER THE PAST 24-30 HOURS. 

OTTO

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

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

LAT...LON   30359380 29259396 28779532 28479690 28929754 
            29629714 30329589