963
AWUS01 KWNH 130936
FFGMPD
FLZ000-131535-

Mesoscale Precipitation Discussion 0430
NWS Weather Prediction Center College Park MD
536 AM EDT Thu Jun 13 2024

Areas affected...south-central FL Peninsula

Concerning...Heavy rainfall...Flash flooding possible

Valid 130935Z - 131535Z

SUMMARY...Locally heavy rainfall is expected over portions of the
south-central FL Peninsula through 15Z. While the coverage of
heavy rainfall is not expected to be widespread, flash flooding
from rainfall rates of over 1 inch in 15 minutes and/or over 3
in/hr will be possible.

DISCUSSION...Local radar imagery from KTBW and GOES East infrared
satellite imagery showed locally heavy rain occurring via warm
topped showers in the vicinity of Tampa Bay at 09Z. These showers
were focused ahead of a weak mesolow to the southwest of SRQ,
steadily approaching the coast where uninhibited instability of
~1500 J/kg MLCAPE was present via the 09Z SPC mesoanalysis.
Convective inhibition increased with inland extent from the Sun
Coast, especially to the north and south which may act to inhibit
farther spreading of heavy rainfall activity in the short term.

A tropical airmass was in place over central to southern FL with
precipitable water values that ranged from 1.8 inches near Tampa
Bay to 2.5 inches over the FL Keys (per satellite derived TPW
imagery). Due to the dominance of warm rain processes, efficient
rainfall production will be capable of high rainfall rates with
1-2 in/hr likely but even greater subhourly rates rainfall of 1+
inches in 15 minutes possible. As the mesolow continues toward the
NE, a short term flash flood threat will exist with increasing
showers and locally intense rainfall rates.

Farther south, an increase in showers and thunderstorms is
expected to occur later this morning, to the southwest of a
broader 850 mb low estimated to be near 30N 80W via LPW imagery.
An axis of low level convergence (which extends up through 850 mb)
was located south of the broader cyclonic circulation east of the
northern FL Peninsula into the eastern Gulf of Mexico. This low
level convergence axis, aided by increasing 825 mb winds per RAP
forecasts, is likely to become a focus for the development of
locally heavy rain into the mid-morning hours, beginning between
11-13Z with increased surface heating. Rainfall rates of 1-2 in/hr
but with subhourly rainfall of 1+ inches in 15 minutes will be
possible atop very wet antecedent conditions due to 4 to 10+
inches of rain which impacted the south-central FL Peninsula over
the past 48 hours.

Otto

...Please see www.wpc.ncep.noaa.gov for graphic product...

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

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

LAT...LON   28298069 27998035 27608014 26897988 26558023
            26038140 26108212 26628252 27318301 27768301
            28028283 28128232 28168174