MESOSCALE PRECIPITATION DISCUSSION 0018
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
315 PM EDT MON APR 07 2014
 
AREAS AFFECTED...NORTHERN FL AND SOUTHEAST GA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 071915Z - 080115Z
 
SUMMARY...A BAND OF THUNDERSTORMS IS SLOWING DOWN AS IT MOVES INTO
THE CENTRAL FL PANHANDLE AND SOUTHERN GA.  DESPITE SLOWLY
DECREASING RAINFALL RATES, REGIONAL FLASH FLOODING REMAINS
POSSIBLE DUE TO THE BAND'S EXPECTED SLOWER MOVEMENT LATER THIS
EVENING.

DISCUSSION...A BAND OF THUNDERSTORMS WITH RAINFALL RATES OF 1-2"
AN HOUR IS BEGINNING TO SLOW DOWN -- MOVING JUST OVER 15 KTS -- AS
IT CROSSES FARTHER INTO THE FL PANHANDLE AND SOUTHERN GA, WELL
AHEAD OF A COLD FRONT CURRENTLY MOVING INTO PENSACOLA WITHIN AN
AREA OF DEEP SOUTHWESTERLY FLOW.  INFLOW AT 850 HPA REMAINS CLOSE
TO 50 KTS PER REGIONAL VAD WIND PROFILES, YIELDING 35-40 KTS OF
0-3 KM SHEAR, SUFFICIENT FOR ORGANIZED CONVECTIVE CLUSTERS. 
PRECIPITABLE WATER VALUES REMAIN NEAR RECORD VALUES FOR EARLY
APRIL -- IN THE 1.75-2" RANGE -- AIDING PRECIPITATION EFFICIENCY.

THE LATEST RAP GUIDANCE INDICATES THAT THE LOW-LEVEL INFLOW/0-3 KM
SHEAR DECREASES TOWARDS 30-35 KTS DURING THE EVENING HOURS, WITH
AXIS BRIEFLY STALLING ACROSS THE EASTERN FL PANHANDLE, NORTHERN FL
PENINSULA, AND COASTAL GA AFTER 23Z AS A SHORTWAVE CURRENTLY IN AL
ESCAPES TO THE NORTHEAST.  CORFIDI VECTORS FROM THE 12Z GFS REMAIN
LIGHT OVER THIS REGION.  CAPE VALUES IN THE GULF OF MEXICO
(UPSTREAM) REMAIN 1000-2000 J/KG PER THE 12Z ARW GUIDANCE, THOUGH
THEY SLOWLY DECREASE ASHORE INTO THE EVENING HOURS.  DESPITE AN
EXPECTATION FOR SLOWLY DECREASING RAINFALL RATES, SLOWING MOVEMENT
TO THE CONVECTIVE LINE/BAND IS EXPECTED TO CONTINUE A RISK FOR
REGIONAL FLASH FLOODING INTO THE NIGHT -- IT IS POSSIBLE THAT THIS
COULD TRANSITION FROM A FLASH FLOOD TO A LONGER DURATION FLOOD
EVENT SIMILAR TO WHAT WAS SEEN ON MARCH 16.  THERE IS A FAIRLY
STRONG SIGNAL WITHIN THE MESOSCALE GUIDANCE FOR 3-5" LOCAL AMOUNTS
NEAR THE COAST OF NORTHERN FL OVER THE NEXT SEVERAL HOURS, AND A
WEAKER/LESS CONSISTENT SIGNAL ACROSS COASTAL GA, WHERE THE
GUIDANCE SHOWS AMOUNTS CLOSER TO 2". 

ROTH

ATTN...WFO...CHS...TBW...JAX...FFC...TAE...

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

LAT...LON   29878540 30448494 31318402 31808321 32138183 31938103
            31628111 30968135 30288149 29648266 29348319 29658354
            29978409 29618476 29568516 29688535 29878540