MESOSCALE PRECIPITATION DISCUSSION 0218
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
917 PM EDT TUE MAY 17 2016
 
AREAS AFFECTED...SOUTHERN FL PENINSULA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 180116Z - 180516Z
 
SUMMARY...A CONVECTIVE LINE IS MOVING THROUGH THE CENTRAL AND
SOUTHERN PENINSULA, WHICH SAW HEAVY RAIN EARLIER TODAY.  HOURLY
RAIN RATES UP TO 2.5", WITH ADDITIONAL LOCAL AMOUNTS OF 2-4",
COULD LEAD TO FLASH FLOODING.

DISCUSSION...AN OUTFLOW BOUNDARY SENT FORTH FROM THE CONVECTIVE
AREA MARCHING ACROSS THE GULF OF MEXICO MONDAY AND TUESDAY HAS LED
TO A PROGRESSIVE CONVECTIVE LINE MOVING ACROSS THE FL PENINSULA AT
A RATE OF 25 KTS.  IN ADVANCE, A COUPLE PERSISTENT SHORT TRAINING
BANDS HAVE BEEN STUCK IN PLACE OVER THE EVERGLADES, DROPPING 4-6"
AMOUNTS PER SOUTH FL WATER MANAGEMENT OBSERVATIONS.  ALSO, LOCAL
AMOUNTS AROUND 8" HAVE FALLEN ACROSS NORTHERN PORTIONS OF ST.
LUCIE COUNTY.  INFLOW AT 850 HPA IS SOUTHWEST AT 20-40 KTS PER VAD
WIND PROFILES, AND MLCAPES REMAIN 2000-3000 J/KG ACROSS THE
SOUTHERN PENINSULA.  PRECIPITABLE WATER VALUES REMAIN IN THE
2-2.25" RANGE, 2.5-3 SIGMAS ABOVE THE MEAN FOR MID-MAY.

THE 12Z ARW APPEARS TO BE HANDLING THE CONVECTIVE PATTERN THE
BEST, WITH MOST OF THE MESOSCALE/CAM GUIDANCE TOO FAR NORTH/TOO
SLOW WITH THE LINE'S MOVEMENT.  URBAN AREAS SHOULD BE THE MOST
SUSCEPTIBLE TO RUNOFF FROM THE INCOMING LINE...PARTICULARLY IN ST.
LUCIE COUNTY AND PORTIONS OF I-75/ALLIGATOR ALLEY IN BROWARD AND
COLLIER COUNTIES WHERE SO MUCH RAIN HAS ALREADY FALLEN.  WITH
HOURLY RAIN RATES UP TO 2.5" AND LOCAL AMOUNTS OF 2-4" POSSIBLE,
FLASH FLOODING REMAINS POSSIBLE UNTIL THE CONVECTIVE LINE CLEARS
THE SOUTHERN PENINSULA IN ABOUT FOUR HOURS.

ROTH

ATTN...WFO...KEY...MFL...MLB...TBW...

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

LAT...LON   28868079 28358048 27758031 26747995 25738017 
            25228038 25058108 25288130 25678142 25858186 
            26268197 26368219 26548226 27538156