MESOSCALE PRECIPITATION DISCUSSION 0007
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1116 AM EDT THU APR 11 2013
 
AREAS AFFECTED...NORTHERN MS/AL TO CENTRAL TN 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 111516Z - 111846Z
 
SUMMARY...GRADUAL INCREASE TO RAIN INTENSITY THROUGH MIDDAY.
ISOLATED FLASH FLOODING POSSIBLE...BUT SOME FACTORS WORKING
AGAINST A HIGHER END EVENT.

DISCUSSION...LAST TWO HOURS HAS SEEN LOCALLY INCREASED INTENSITY
WITH SMALL LEADING LINE SEGMENTS AND ONE REPORT OF FLOODING FROM
NORTHEAST MS. STORMS LIKELY BASED NEAR THE SURFACE PER JAN
SOUNDING...BUT MORE ROBUST SURFACE BASED CONVECTION LIKELY BY
MIDDAY AS PRECIPITATION WORKS INTO THE AREA CURRENTLY RECEIVING
BETTER HEATING OVER NORTHERN AL/CENTRAL TN. THOUGH PW VALUES AND
CAPE PROFILES SUPPORT DEEP UPDRAFTS WITH HEAVY RAIN RATES...THE
MORE ROBUST CONVECTION WILL ALSO YIELD STRONGER COLD POOLS AND
FORWARD PROPAGATION. THIS COMBINED WITH A SLIGHT INCREASE TO
WESTERLY COMPONENT OF MID LEVEL WINDS...SHOULD YIELD ENOUGH MOTION
TO PREVENT MORE SIGNIFICANT FLASH FLOOD PROBLEMS. THIS ESPECIALLY
TRUE OVER MS/AL WHERE FFG IS HIGHER.

SOME OF THE BETTER PERFORMING HI-RES MODELS RIGHT NOW...NSSL WRF
AND WRF-ARW...SUGGEST GENERAL ACCUMULATIONS 1.5 TO 2 INCHES AT A
GIVEN LOCATION...WITH LOCALLY HIGHER AMOUNTS. THIS AGREES WITH
RECENT RADAR-DERIVED RAINFALL NEAR THE HEAVIER LINE SEGMENTS.


ATTN...WFO...MRX...OHX...BMX...HUN...MEG...JAN...

LAT...LON   36518769 34848861 34058907 33648922 33168875 33098821
            33418715 34128645 34838585 35218551 35738522 36218504
            36598545 36518769