MESOSCALE PRECIPITATION DISCUSSION 0307
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
156 PM EDT SUN JUL 05 2015
 
AREAS AFFECTED...SERN ARKANSAS...NERN LOUISIANA TOWARD THE WRN
FLORIDA PANHANDLE 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 051756Z - 052256Z
 
SUMMARY...THE FLASH FLOOD THREAT WILL CONTINUE FOR THE REMAINDER
OF THE AFTERNOON FOR PORTIONS OF THE LOWER MISSISSIPPI VALLEY AND
THE CNTRL GULF COAST WHERE VERY HEAVY RAINFALL RATES WILL BE
POSSIBLE. THE THREAT IS EXPECTED TO BE SOMEWHAT SHORT TERM BEFORE
OUTFLOW SWEEPS INTO THE GULF.

DISCUSSION...17Z OBSERVATIONS SHOWED AN MCV FROM EARLY MORNING
CONVECTION THAT WAS TRACKING EWD ACROSS CNTRL MISSISSIPPI ALONG
WITH A RELATED OUTFLOW BOUNDARY EXTENDING WEST-EAST ACROSS N-CNTRL
LOUISIANA INTO MISSISSIPPI. REGIONAL RADAR CONTINUED TO SHOW
REGENERATING CONVECTION ACROSS SERN ARKANSAS WHICH IS THE
IMMEDIATE FLASH FLOOD THREAT...BUT CONVECTION FOR THIS REGION IS
EXPECTED TO SUBSIDE OVER THE NEXT HOUR OR SO AS AN UPPER LEVEL
TROUGH AXIS OVER THE REGION PROGRESSES EWD. 

THE FLASH FLOOD FOCUS IS SHIFTING TO THE SOUTH...NEAR A
CONVECTIVELY INDUCED MESO-LOW AND ENHANCED LOW LEVEL FLOW ACROSS
SRN MISSISSIPPI...WHERE LOW LEVEL CONFLUENCE AND UNIDIRECTIONAL
WLY FLOW ARE PRESENT. UPPER DIFFLUENCE SHOULD REMAIN PRESENT
ACROSS THE GULF COAST HELPING TO ENHANCE LIFT. 17Z GPS PWAT VALUES
FROM NEW ORLEANS LOUISIANA AND MOBILE ALABAMA SHOWED 2.05 AND 2.17
INCHES RESPECTIVELY...WHICH SHOULD ALLOW FOR EFFICIENT RAINFALL
RATES. ALTHOUGH PORTIONS OF THE CNTRL GULF COAST HAVE SEEN BELOW
AVERAGE RAINFALL OVER THE PAST WEEK...SOME OF THE HI-RES MODELS
SHOWED POTENTIAL FOR 4-5 INCHES IN A FEW SPOTS ACROSS NERN
LOUISIANA...SRN MISSISSIPPI AND ALONG THE CNTRL GULF COAST BY 22Z.
AFTERWARD...THE OUTFLOW BOUNDARY IS EXPECTED TO SWEEP SWD INTO THE
GULF...BUT THERE ARE SOME HINTS THAT CONVECTION MAY HANG UP ALONG
THE WRN END OF THE OUTFLOW BEYOND 22Z NEAR THE CNTRL
LOUISIANA/MISSISSIPPI BORDER...CONTINUING A FLASH FLOOD THREAT.

OTTO

ATTN...WFO...JAN...LCH...LIX...LZK...MOB...SHV...TAE...

ATTN...RFC...LMRFC...SERFC...

LAT...LON   33999148 33309077 32078904 31438667 30208626 
            29998783 30138912 30399042 30639182 31039232 
            32659223 33639246