MESOSCALE PRECIPITATION DISCUSSION 0744
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
325 PM EDT SUN AUG 27 2017

AREAS AFFECTED...SOUTHWEST FL

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 271925Z - 272325Z

SUMMARY...CONVECTION TRAINING FROM THE GULF OF MEXICO COULD
PRODUCE A FLASH FLOOD THREAT ACROSS PORTIONS OF SOUTHWEST FL THAT
RECEIVED HEAVY RAINFALL SATURDAY INTO SATURDAY NIGHT.

DISCUSSION...THE KTBW RADAR SHOWED AN AXIS OF CONVECTION EXTENDING
FROM THE EASTERN GULF OF MEXICO ACROSS PORTIONS OF SOUTHWEST FL
THIS AFTERNOON. THE CONVECTION IS MOVING ALONG A LOW LEVEL
CONVERGENCE AXIS NEAR KFMY/KRSW...WHERE PRECIPITABLE WATER VALUES
REMAIN NEAR 2.50 INCHES (PER THE MOST RECENT RAP ANALYSIS).

THE GOES-16 CLEAN IR LOOP SHOWED COOLING TOPS ALONG THE LOW LEVEL
CONVERGENCE AXIS...AND THE KTBW RADAR INDICATED HOURLY RAINFALL
RATES NEARING 1.50 INCHES. INSTABILITY IS RELATIVELY LOW OVER THIS
AREA (WITH MLCAPE WAS GENERALLY BETWEEN 500-1000 J/KG). GIVEN THE
DEEP MOISTURE IN PLACE...THE CONVECTION SHOULD MAKE THE MOST OF
THE AVAILABLE INSTABILITY...AS WARM RAIN PROCESSES RESULT IN HIGH
HOURLY RAINFALL RATES.

THE MOST RECENT HRRR SHOWED AN AXIS OF 4.00 TO 6.00 INCHES OF
RAINFALL NORTH OF THIS AREA...BUT BASED ON THE RADAR
PRESENTATION...THE HRRR APPEARS TO BE TOO FAR NORTH WITH THE
MAXIMUM QPF AXIS. THE ADDITIONAL RAINFALL COULD RESULT IN AN
ENHANCED FLASH FLOOD THREAT IN THE FORT MYERS/CAPE CORAL
AREA...WHERE HEAVY RAINFALL OCCURRED SATURDAY INTO SATURDAY NIGHT.

HAYES

ATTN...WFO...MFL...TBW...

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

LAT...LON   27048199 26288134 25638121 25658151 26208200
            26998228