MESOSCALE PRECIPITATION DISCUSSION 0407
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
413 PM EDT SUN AUG 02 2015
 
AREAS AFFECTED...PORTIONS OF THE NORTHERN AND CENTRAL FL
PENINSULA...SOUTHERN GA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 022000Z - 030200Z
 
SUMMARY...ADDITIONAL FLOODING PROBLEMS ARE EXPECTED AS INTENSE
SHOWERS AND THUNDERSTORMS DEVELOP AND CONCENTRATE OVER AREAS THAT
HAVE SEEN VERY HEAVY RAINFALL OVER THE LAST SEVERAL DAYS.

DISCUSSION...THE MESOSCALE ENVIRONMENT IS BECOMING MORE CONDUCIVE
FOR VERY HEAVY SHOWERS AND THUNDERSTORMS TO REDEVELOP AND BECOME
CONCENTRATED OVER AREAS OF NORTHERN FL AND ALSO PARTS OF SOUTHERN
GA AS CYCLONIC LOW TO MID LEVEL FLOW PERSISTS OVER THE AREA...AND
DEEP MOISTURE CONTINUES TO ADVANCE INLAND OFF THE GULF OF MEXICO.
THE LAST COUPLE OF HOURS HAVE SEEN AN UPTICK IN SURFACE-BASED
INSTABILITY THROUGH DIURNAL HEATING OVER SOUTHERN GA AND NORTHERN
FL...WITH THE RESULT BEING THE DEVELOPMENT OF NUMEROUS CLUSTERS OF
COLD-TOPPED CONVECTION. GIVEN PWATS OF 2.2 TO 2.4 INCHES...SLOW
CELL MOTION AND A FEW CELL MERGERS...SOME VERY HEAVY SHORT-TERM
RAINFALL AMOUNTS ARE EXPECTED.

MEANWHILE...CLOSER TO APPALACHEE BAY WHERE A WELL-DEFINED LOW
CENTER IS SITUATED...THE SITUATION THIS EVENING AGAIN MAY BECOME
QUITE INTERESTING. PERSISTENT AND WELL-DEFINED GULF OF MEXICO
INFLOW WITH DEEP MOISTURE TRANSPORT/CONVERGENCE AROUND THE
SOUTHERN AND EASTERN FLANKS OF THE LOW CENTER IS EXPECTED TO FOCUS
LOCALLY STRONG CONVECTIVE BANDS WITH VERY INTENSE RAINFALL RATES
THAT MAY REACH 2.5 INCHES/HR.

THE HIRES MODELS INCLUDING THE 12Z NAM-CONEST/12Z ARW/12Z NMMB AND
12Z NSSL-WRF ALL AGREE WITH SOME MINOR PLACEMENT
DIFFERENCES...THAT SOME VERY INTENSE BANDING OF HEAVY RAINFALL MAY
SET UP ACROSS PORTIONS OF DIXIE...LEVY...CITRUS AND HERNANDO
COUNTIES. ALREADY AN UPTICK IN CONVECTION IS NOTED IN RADAR
IMAGERY...AND THE LATEST GUIDANCE SUGGESTS ADDITIONAL RAINFALL
TOTALS OF 3 TO 6 INCHES FALLING ACROSS PORTIONS OF THESE COUNTIES
OVER THE NEXT 6 HOURS...WITH MORE LIKELY AFTER THIS PERIOD. THIS
WILL SIGNIFICANTLY EXACERBATE ALREADY SERIOUS FLOODING PROBLEMS
THAT HAVE IMPACT THIS REGION OVER THE LAST SEVERAL DAYS.

ORRISON

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

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

LAT...LON   31618234 31428141 30758112 29978135 29358203 
            28378227 28048265 28188295 28498306 28958306 
            29278321 29648362 29848399 30388408 31238348