MESOSCALE PRECIPITATION DISCUSSION 0146...RESENT FOR AWIPS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1120 AM EDT SUN JUN 22 2014
 
AREAS AFFECTED...PORTIONS OF NORTHEAST TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 221418Z - 222018Z
 
SUMMARY...THUNDERSTORMS WITH HEAVY RAINFALL ARE BECOMING MORE
ORGANIZED AS A COLD POOL BECOMES ESTABLISHED AND 850 HPA INFLOW
SLIGHTLY INCREASES.  A FEW SPOTS COULD RECEIVE FLASH FLOODING.

DISCUSSION...A MID-LEVEL SHORTWAVE PARTIALLY ASSOCIATED WITH THE
MESOCYCLONE WHICH MOVED UP THE RIO GRANDE VALLEY 2-3 DAYS AGO IS
MOVING ACROSS NORTH-CENTRAL TX, HELPING TO STREAM IN MOISTURE
ALOFT FROM THE EASTERN PACIFIC AND ACTS AS THE WESTERN EDGE OF A
GROWING CONVECTIVE COMPLEX WITH COOLING TOPS.  AT LOW-LEVELS, GULF
INFLOW IS SLOWLY INCREASING AS RECENT VAD WIND PROFILES HAVE
INCREASED TO 30 KTS AT 850 HPA, WHICH IS DOUBLE THE MEAN 850-400
HPA WIND FLOW, WHICH SHOULD ACT TO INCREASE PRECIPITATION
EFFICIENCY.  CAPES NEARBY ARE 1000 J/KG, WITH UPSTREAM CAPES OF
2000-3000 J/KG ACROSS SOUTH-CENTRAL AND SOUTHEAST TX. 
PRECIPITABLE WATER VALUES ARE NEAR 2", NEAR THE 90TH PERCENTILE
FOR LATE JUNE.  THESE INGREDIENTS REACH THE THRESHOLD FOR THE WET
MULTI-CELL ENVIRONMENT.

THERMAL CONTRAST AT THE LEADING EDGE OF THE COLD POOL IS EXPECTED
TO INCREASE DUE TO DAYTIME HEATING, MAKING ITS EDGE AN
INCREASINGLY EFFECTIVE FOCUS FOR CONVECTION.  CAPE VALUES ARE
EXPECTED TO REMAIN SIMILAR ACROSS THE REGION OVER THE NEXT SEVERAL
HOURS PER THE 00Z ARW, WITH A SLIGHT INCREASE IN 850 HPA INFLOW
POSSIBLE INTO THE AFTERNOON PER RECENT RAP RUNS.  CORFIDI VECTORS
ARE LIGHT AND INDICATE POSSIBLE PROPAGATION INTO THE LOW-LEVEL
INFLOW.  RAINFALL RATES OF 2.5" PER HOUR ARE POSSIBLE IN THIS
ENVIRONMENT, WHICH COULD CHALLENGE THE THREE HOUR FLASH FLOOD
GUIDANCE VALUES OF 3" WHERE CELLS TRAIN/BACKBUILD.  A FEW SPOTS
COULD RECEIVE FLASH FLOODING IN THIS REGION.

ROTH

ATTN...WFO...FWD...OUN...

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

LAT...LON   33639716 33859797 33409833 31839834 31329782 31519696
            32189663 33639716