MESOSCALE PRECIPITATION DISCUSSION 0042
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1151 AM EDT TUE APR 14 2015
 
AREAS AFFECTED...CNTRL GULF COAST INTO SRN MISSISSIPPI/ALABAMA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 141551Z - 142051Z
 
SUMMARY...ADDITIONAL FLASH FLOODING WILL BE POSSIBLE INTO THE LATE
AFTERNOON ACROSS PORTIONS OF THE CNTRL GULF COAST INTO SRN
MISSISSIPPI/ALABAMA WITH SLOW MOVING HEAVY RAINFALL CAPABLE OF 2
IN/HR RATES AND 3 HRLY RATES IN THE 3 TO 4 INCH RANGE. 

DISCUSSION...IR/RADAR IMAGERY FROM 15Z SHOWED WIDESPREAD
CONVECTION EXTENDING FROM THE UPPER TEXAS COAST TO SRN MISSISSIPPI
WITH THE HEAVIEST RAINFALL OCCURRING OVER ERN LOUISIANA WITH
OBSERVED RAINFALL RATES OVER 2 IN/HR REPORTED NORTH OF LAKE
PONTCHARTRAIN EARLIER THIS MORNING. PRECIPITABLE WATER ACROSS THIS
REGION RANGES BETWEEN 1.75 AND 2.00 INCHES...WHICH IS 2 TO 3
STANDARD DEVIATIONS ABOVE APRIL MEANS. EMBEDDED WITHIN THE GULF
COAST CONVECTION ARE SEVERAL SMALLER SCALE VORTICITY MAXIMA WHICH
ARE EXPECTED TO TRACK NEWD INTO SRN ALABAMA/MISSISSIPPI THROUGH
THE AFTERNOON VIA SOUTHWEST FLOW ALOFT AIDING IN BURSTS OF HEAVIER
RAINFALL.

WHILE SOME OF THE 3000-4000 J/KG CAPE PER 12Z LIX RAOB IS BEING
EXHAUSTED...LARGE CAPE STILL EXISTS JUST OFFSHORE OF THE GULF
COAST TO THE WRN FLORIDA PANHANDLE. AS EMBEDDED VORTICITY MAXIMA
ADVECT NEWD...850-700 MB FLOW WILL INCREASE ALLOWING DEEPER
MOISTURE AND INSTABILITY TO ADVECT INTO THE THREAT REGION WHICH
WILL BE CAPABLE OF FLASH FLOOD PRODUCING RAINS. THIS WILL
ESPECIALLY BE TRUE WHERE 48 HR RAINFALL TOTALS ARE IN THE 3 TO 6
INCH RANGE WITH HIGHER LOCAL MAXIMA. RECENT RUNS OF THE HRRR AND
THE 00Z NMM/ARW SUPPORT THE THREAT AREA RECEIVING ADDITIONAL HEAVY
RAINFALL...BUT COULD BE UNDERDONE ON THE AMOUNTS.

OTTO

ATTN...WFO...BMX...JAN...LIX...MOB...

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

LAT...LON   32048809 31668711 30598724 30068828 29998871 
            30028941 30419079 31229069 31668927