MESOSCALE PRECIPITATION DISCUSSION 0126
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1004 AM EDT MON MAY 25 2015
 
AREAS AFFECTED...NORTHERN AND CENTRAL TEXAS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 251404Z - 251904Z
 
SUMMARY...FLASH FLOODING IS POSSIBLE ACROSS PORTIONS OF NORTHERN
AND CENTRAL TEXAS IN ASSOCIATION WITH A FORWARD PROPAGATING MCS.

DISCUSSION...RADAR AND ADDITIONAL ANALYSES SHOW THE EARLY STAGES
OF A FORWARD PROPAGATING MCS FORMING ACROSS WEST CENTRAL TEXAS IN
ASSOCIATION WITH A COMPACT AND VIGOROUS SHORTWAVE TROUGH.  WHILE
INTEGRATED MOISTURE VALUES ARE ONLY MODEST...STEEP MID LEVEL LAPSE
RATES AND DEEP/STRONG ASCENT ARE SUPPORTING DEEP CONVECTION WITH
HOURLY RAINFALL RATES NEARING 2 INCHES...WHICH IF SUSTAINED IS
SUFFICIENT TO EXCEED LOCAL FFG VALUES.

THE 00Z GEM REGIONAL AND 00Z NAM CONUS NEST BEST ALIGN WITH THE
OBSERVED RADAR PATTERN AT FORECAST ISSUANCE AND THUS WERE USED TO
EXTRAPOLATE THE MCS AS IT CONTINUES TO GROW INTO THE AFTERNOON. 
THE MOST LIKELY AREA FOR RATES TO EXCEED GUIDANCE WILL BE ALONG
THE PATH OF THE MESOLOW THAT IS EXPECTED TO REMAIN ALONG BUT
MAINLY NORTH OF I-20 AND WEST OF I-35 THROUGH 18-19Z.  ANOTHER
POSSIBLE AREA WILL BE NORTHWEST OF SAN ANTONIO...WHERE SUPERCELLS
IN A VERY HIGH CAPE ENVIRONMENT MAY PRODUCE SOME EXTREME RAINFALL
RATES. 

JAMES

ATTN...WFO...EWX...FWD...LUB...MAF...OUN...SJT...

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

LAT...LON   33649958 33619812 32909734 31179727 29899803 
            29349945 29690058 30540038 31360020 32170053 
            32510111 33080082