MESOSCALE PRECIPITATION DISCUSSION 0213
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
545 AM EDT FRI JUL 18 2014
 
AREAS AFFECTED...SOUTHERN TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 180940Z - 181330Z
 
SUMMARY...A SLOW-MOVING CLUSTER OF INTENSE THUNDERSTORMS CONTINUES
OVER PORTIONS OF SOUTHERN TX. INTENSE RAINFALL RATES WILL CONTINUE
TO FOSTER THE POTENTIAL FOR FLASH FLOODING THE NEXT COUPLE OF
HOURS.

DISCUSSION...THE LATEST IR SAT IMAGERY SHOWS VERY COLD CLOUDS TOPS
IN ASSOC WITH WHAT IS ESSENTIALLY A SLOW-MOVING MCS OVER PARTS OF
SOUTHERN TX. MOST OF THE ACTIVITY IS FOCUSED GENERALLY SOUTH OF A
LINE FROM KSAT TO KHDO TO NEAR KUVA. THE CONVECTION IS FOCUSED
NEAR A WELL-DEFINED FRONTAL ZONE AND IS BEING SUPPORTED BY THE
TRANSPORT OF MOIST/UNSTABLE AIR UP THE LWR RIO GRANDE VLY. WV
IMAGERY ALSO SUGGESTS FAIRLY DIV FLOW ALOFT RIGHT NOW TOO WHICH IS
YIELDING SOME LARGER SCALE ASCENT.

THERE IS SOME POTENTIAL FOR SOME ADDITIONAL BACK-BUILDING OF THIS
CONVECTION LOCALLY FOR A COUPLE MORE HOURS...AND RAINFALL RATES IN
THE SHORT-TERM SHOULD CONTINUE TO BE VERY INTENSE AND AS HIGH AS 3
TO 4 INCHES/HR. SO SOME POTENTIAL FOR FLASH FLOODING STILL EXISTS.

HOWEVER...THE LATEST HI-RES MODEL GUIDANCE GENERALLY SUPPORTS THE
ACTIVITY WEAKENING AFTER 12Z...WITH THERMODYNAMICS BECOMING A BIT
LESS FAVORABLE FOR SUSTAINABLE CONVECTION WITH TIME. WILL CONTINUE
TO MONITOR.

ORRISON

ATTN...WFO...CRP...EWX...BRO...

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

LAT...LON   28429762 27559746 26749751 26299791 26229848 26639922
            27119967 27780020 28520059 29220078 29679999 29669900
            29369819 28429762