Mesoscale Precipitation Discussion 0261
NWS Weather Prediction Center College Park MD
535 PM EDT Mon May 12 2025

Areas affected...Southeast FL

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

Valid 122135Z - 130035Z

SUMMARY...A band of heavy showers and thunderstorms will be
approaching the urban corridor of southeast FL over the next
couple of hours. As this activity crosses the region early this
evening, and urban flash flood threat will exist.

DISCUSSION...The latest GOES-E IR satellite imagery along with
regional radar data shows a band of heavy showers and
thunderstorms gradually crossing south FL, with the activity
gradually encroaching on the I-95 urban corridor of southeast FL.

The activity has been intensifying over the last hour with cooling
convective tops noted, and this intensification trend is being
facilitated by rather strong low-level moisture convergence and a
moderate to strongly unstable airmass characterized by MLCAPE
values of 1500 to 2000 J/kg. Meanwhile, it is very moist with PWs
of 2.0 to 2.25 inches which is locally 3+ standard deviations
above normal.

Rainfall rates with the approaching convective band are expected
to be very high considering a well-defined deep tropical airmass
and robust instability. Some rainfall rates may be capable of
reaching 2 to 3 inches/hour, with even some sub-hourly rainfall
totals of as much as 1.5 inches in just 20 to 30 minutes possible.

The convection is moving fairly slowly, but steadily off to the
east, and should advance into the I-95 urban corridor of southeast
FL from West Palm Beach down to Fort Lauderdale and the Miami
metropolitan area within the next 1 to 2 hours. Given the high
rainfall rates and relatively slow cell-motions, some rainfall
totals by mid-evening could reach 3 to 4 inches.

These additional rains coupled with local sensitivities from the
rainfall that occurred this morning will pose a concern for flash
flooding over the next few hours. However, even the high rainfall
rates alone impacting the I-95 corridor of southeast FL this
evening will drive a notable urban flash flood threat.

Orrison

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

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

LAT...LON   27468013 26727992 25888000 25238035 25388079
            26308052 27428054