MESOSCALE PRECIPITATION DISCUSSION 0699
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
458 PM EST FRI DEC 25 2015
 
AREAS AFFECTED...SRN MS/AL BORDER...NEWD INTO NRN MS...NRN
AL...NWRN GA...SERN TN 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 252158Z - 260300Z
 
SUMMARY...SIGNIFICANT...WIDESPREAD FLASH FLOODING IS EXPECTED TO
CONTINUE THROUGH 03Z FOR N-CNTRL ALABAMA WITH SIGNIFICANT FLASH
FLOOD THREATS EXTENDING SOUTHWEST TO CNTRL LOUISIANA AND NORTHEAST
TO SRN TENNESSEE. 

DISCUSSION...REGIONAL RADAR TRENDS OVER THE PAST 2 HOURS HAVE
SHOWN WHAT HAD BEEN A NEARLY STATIONARY AXIS OF HEAVY
RAINFALL...EXTENDING FROM NRN MISSISSIPPI TO NWRN GEORGIA...HAS
STARTED TO SLOWLY SINK SOUTH. MEANWHILE...TRAINING AXES OF
THUNDERSTORMS ACROSS THE CNTRL-NRN LOUISIANA/MISSISSIPPI BORDER
HAVE TAKEN ADVANTAGE OF ESTIMATED MLCAPE RANGING FROM 1000-1500
J/KG...PER RECENT SPC MESOANALYSIS PAGE. A CORRIDOR OF 30-40 KT
FLOW IN THE 850-700 MB LAYER...CONFIRMED WITH VAD WIND PROFILE
DATA...HAS BEEN ORIGINATING IN CNTRL LOUISIANA AND TRANSPORTING
HIGHLY ANOMALOUS MOISTURE NEWD INTO PORTIONS OF THE SOUTH. 

A SLOWLY SWD SINKING COLD POOL...STRETCHING FROM N-CNTRL LOUISIANA
INTO NRN ALABAMA HAS ALLOWED FOR THE RECENT SWD MOVEMENT OF HEAVY
RAIN...WHILE ADDITIONAL CONVECTIVE ACTIVITY HAS BECOME RATHER
ROBUST SOUTH OF THIS BOUNDARY INTO LOUISIANA AND S-CNTRL
MISSISSIPPI. AN 850-700 MB MOISTURE FLUX MAXIMUM WILL CONTINUE
OVER THE NEXT 5-6 HOURS...VIA RAP GUIDANCE...FROM LOUISIANA INTO
MISSISSIPPI...HELPING TO REFOCUS THE HEAVIEST RAINFALL SOUTH INTO
CNTRL MISSISSIPPI AND ALABAMA THROUGH 00Z. THEREFORE...THE
ORIENTATION OF THE FLASH FLOOD THREAT WILL ADJUST...EXTENDING FROM
SOUTHWEST TO NORTHEAST. 3-5 INCHES OF ADDITIONAL RAINFALL WILL BE
POSSIBLE IN THE VICINITY OF THE N-CNTRL MISSISSIPPI/ALABAMA
BORDER...A BIT SOUTH OF THE HEAVIEST RAINFALL FROM EARLIER THIS
AFTERNOON.

OTTO

ATTN...WFO...BMX...FFC...HUN...JAN...LCH...LIX...MEG...MOB...
MRX...SHV...

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

LAT...LON   35118642 35048444 34938399 34568390 34118469 
            33478585 32638721 31938847 31039043 30879244 
            31349304 32119274 32579165 33379006 34158876