Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1203 PM EDT Tue Apr 8 2025

Day 1
Valid 16Z Tue Apr 08 2025 - 12Z Wed Apr 09 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
SOUTH FLORIDA...

...16z update...

Excessive rainfall potential will likely remain confined to peak
heating hours prior to 00z (8pm EDT) today. Convective ingredients
remain almost the same as the overnight issuance with some subtle
downward trends on PWATs (1-1.5") and CAPE (1000-2000 J/kg). Thus,
non NAM CONEST CAMs have suggested drier/more progressive solutions
in QPF. Localized flash flooding is still possible due to a potential
synoptic seabreeze--cold front connection.

Kebede


...Previous Discussion...

Deep southwest flow is occurring ahead of an advancing cold front
across the FL Peninsula this morning. Precipitable water values
have increased to 1.7-1.9" in association with the front, and SB
CAPE should maximize in the 2000-2500 J/kg range per the 00z HREF.
Low-level inflow (non-zero) and effective bulk shear (20-40 kts)
are more than sufficient for convective organization, across South
FL typically, and whether or not a localized flash flood risk
fully materializes depends upon whether or not an East Coast
seabreeze front can develop and focus convection with the well-
timed arrival of the front (near peak daytime heating), which
could anchor convection in the large urban area of South FL as it
is unlikely to progress inland within this synoptic pattern. In
this sort of atmosphere, hourly rain totals to 2.5" (as depicted by
CAMs) and overall totals to 5" are possible (as 00z HREF 40-km
neighborhood probabilities for 3" exceedance are as high as 30-60%
along the immediate Gold Coast. Considering the urban environment,
ingredients available, and mesoscale guidance signal, maintained
the inherited Marginal Risk for South FL.

Churchill/Roth


Day 2
Valid 12Z Wed Apr 09 2025 - 12Z Thu Apr 10 2025

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Churchill


Day 3
Valid 12Z Thu Apr 10 2025 - 12Z Fri Apr 11 2025

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Churchill


Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt