MESOSCALE PRECIPITATION DISCUSSION 0103
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
746 PM EDT THU MAR 31 2016
 
CORRECTED FOR TYPO IN AREAS AFFECTED

AREAS AFFECTED...NERN LOUISIANA...CNTRL MISSISSIPPI...CNTRL ALABAMA
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 312248Z - 010430Z
 
SUMMARY...ONGOING CONVECTION ACROSS THE LOWER MISSISSIPPI VALLEY
SHOULD CONTINUE TO INCREASE LATE THIS EVENING WITH REPEATING CELLS
FROM WSW TO ENE. FLASH FLOODING WILL BE POSSIBLE FROM NERN
LOUISIANA INTO CNTRL MISSISSIPPI/ALABAMA THROUGH 04Z.

DISCUSSION...RADAR TRENDS OVER THE PAST COUPLE OF HOURS HAVE SHOWN
INCREASING COVERAGE OF THUNDERSTORMS FROM NERN LOUISIANA INTO
CNTRL MISSISSIPPI. THESE STORMS ARE DEVELOPING AHEAD OF A COLD
FRONT WITHIN AN ENVIRONMENT CHARACTERIZED BY ROUGHLY 1000-2000
J/KG MLCAPE ACCORDING TO RECENT RAP/HRRR RUNS AND THE SPC
MESOANALYSIS. GPS PRECIPITABLE WATER PLOTS SHOW A MAX OF 1.7 TO
1.8 INCHES LOCATED IN CNTRL TO SRN LOUISIANA AND VAD WIND PLOTS AT
700 MB INDICATE A CORRIDOR OF STRONGER FLOW...40-50 KTS...FROM WRN
LOUISIANA INTO WRN MISSISSIPPI. FARTHER TO THE SOUTHWEST...WATER
VAPOR IMAGERY AND GOES HD WINDS INDICATE THE POSSIBILITY OF A
MID-LEVEL SPEED MAX OF 65-75 KTS CROSSING THE LOWER RIO GRANDE
VALLEY...AND ACCORDING TO RECENT MODEL GUIDANCE...THIS FEATURE IS
EXPECTED TO CONTINUE NEWD...REACHING THE TEXAS/LOUISIANA BORDER BY
03-06Z. 

THE COVERAGE OF CONVECTION IS FORECAST TO INCREASE ACROSS CNTRL
MISSISSIPPI THROUGH 00Z...WHILE GRADUALLY TRANSLATING ENEWD INTO
ALABAMA. MEANWHILE...THE APPROACH OF THE COLD FRONT FROM THE WEST
AND POSSIBLE MID-LEVEL SPEED MAX DESCRIBED ABOVE IS EXPECTED TO
CONTINUE THE REGENERATION OF CONVECTION NEAR THE NRN
LOUISIANA/MISSISSIPPI BORDER WITH THESE CELLS REPEATING OVER SOME
OF THE SAME AREAS INTO MISSISSIPPI AND ALABAMA THROUGH 04Z. THIS
MAY LEAD TO FLASH FLOOD CONCERNS AS A CONSENSUS OF THE LATEST
GUIDANCE BEST HANDLING THE EVENT SO FAR INCLUDING THE 
HRRR...HRRR_EXP...12Z ARW...SUPPORT 6 HOUR RAINFALL TOTALS OF 3-6
INCHES ACROSS THE MPD THREAT AREA. THE HEAVIEST RAINFALL IS
EXPECTED TO STAY LARGELY SOUTH OF HEAVY RAINFALL FROM WED NIGHT
WHICH HAS SIGNIFICANTLY LOWERED FFG...BUT CERTAINLY ANY LOCALIZED
TRAINING FARTHER NORTH WOULD ALSO EXACERBATE FLASH FLOOD CONCERNS.

OTTO

ATTN...WFO...BMX...HUN...JAN...MEG...MOB...SHV...

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

LAT...LON   34048669 33968550 32878569 32168718 31918863 
            31699087 31779229 32209238 32639200 32999116 
            33598937 33878762