MESOSCALE PRECIPITATION DISCUSSION 0058
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
910 AM EDT TUE MAY 21 2013
 
AREAS AFFECTED...SOUTHEASTERN OK...WESTERN AR...EXTREME NORTHERN
TX 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 211308Z - 211608Z
 
SUMMARY...A SOLID LINE OF CONVECTION HAS DEVELOPED FROM SSW TO NE
FROM SPS TO FSM. THIS ACTIVITY IS BEGINNING TO TRAIN AND BACKBUILD
WHICH SHOULD LEAD TO FLASH FLOODING THIS MORNING.

DISCUSSION...A LINE OF CONVECTION OUT AHEAD OF A FORMIDABLE
SURFACE COLD FRONT HAS FORMED IN AN AXIS OF INCREASING MOISTURE
CONVERGENCE EARLY THIS MORNING. ALSO AHEAD OF THIS FRONT IS AN
ANOMALOUS POOL OF DEEP LOW LEVEL TROPICAL MOISTURE W/ PWS AOA 1.5
TO 2 INCHES. THE GFS AND ECMWF INDICATE THESE VALUES 1.5 TO 2
TIMES ABOVE AVG IN A ZONE WHERE WINDS FROM THE SURFACE TO 700MB
BECOMING PARALLEL. FFG IN THIS AREA RANGE FROM 1 TO 1.5 INCHES
WITHIN AN HR AND ADD IN THE TRAINING/BACKBUILD THREAT... FLASH
FLOODING APPEARS LIKELY DESPITE MESOSCALE ACTIVITY TYPICALLY
APPROACHING A MIN AT THIS HR OF THE DAY. EXPECT 2 TO 3 INCH
AMOUNTS WITH LOCALLY HIGHER VALUES WITH LIKELY FLASH FLOODING...
AS THE HEAVY CONVECTIVE RAINS DRIFT SOUTH AND EAST.  

MUSHER


ATTN...WFO...LZK...SHV...TSA...FWD...OUN...

LAT...LON   34039428 34869338 35789332 35459570 34989699 34679824
            34459917 33819992 33449894 33419757 33639581 34039428