FOUS30 KWBC 171600
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1100 AM EST Tue Dec 17 2024

Day 1
Valid 16Z Tue Dec 17 2024 - 12Z Wed Dec 18 2024

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG PORTIONS OF
THE EAST CENTRAL TO SOUTHEAST COAST OF FLORIDA...

...16Z update...

12Z soundings from MFL and KEY showed PW values of 1.5 and 1.7=20
inches, respectively, or near the 90th percentile for mid-
December. Low level easterly flow is expected to support
showers/thunderstorms moving inland during the day today with an
increasing threat for slow moving/stalled cells late today and
overnight along an expected coastal/near-coastal convergence axis.=20

925-850 mb winds of 15 to 20+ kt are forecast by the latest
guidance with a shift toward more of a southeasterly direction
later tonight. The 12Z HREF indicated neighborhood probabilites=20
for 5 inches in 24 hours (ending 12Z Wednesday) of 50-60 percent
and while these probablities have come down and are largely driven
by the more bullish 12Z NAM_nest and ARW2, a low end threat for=20
localized flash flooding will remain through 12Z Wednesday for the=20
eastern and southeastern FL Peninsula.=20

Otto

...previous discussion follows...


Model consensus is for increasingly active showers late Tuesday=20
afternoon into Tuesday night/early Wednesday along the east central
to southeast coast of Florida. Low level easterly to southeasterly
flow in an axis of PW values 1.5 to 2+ standard deviations above=20
the mean expected to persist into the east central to southeast=20
Florida coast, with models showing an axis of defined boundary=20
layer convergence in this low level inflow axis parallel to the=20
east central to southeast coast. There will be potential for very=20
slow moving cells along the coastal regions, supporting locally=20
very heavy rainfall amounts and an urban flash flood threat. HREF=20
neighborhood probabilities are high (50-90%) for 3"+ amounts from=20
Cape Canaveral, south to Miami, while the 5"+ neighborhood=20
probabilities are high (60-90%) from near West Palm Beach, south to
Miami. The best hi res overlap, evident in the greatest EAS=20
probabilities for 2"+ amounts, is from near West Palm, south to=20
just north of Miami.

Oravec


Day 2
Valid 12Z Wed Dec 18 2024 - 12Z Thu Dec 19 2024

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

Oravec


Day 3
Valid 12Z Thu Dec 19 2024 - 12Z Fri Dec 20 2024

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

Oravec


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=
v/qpf/94epoints.txt__;!!DZ3fjg!49BE_CbALdvdEn84h2xVkzoTVoqIoe2OP5VB5afrMUnq=
s5G8ac0tKrZNiJ4BftTjoDJCVJFRt0D0VFiKRXAoC2qOClA$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=
v/qpf/98epoints.txt__;!!DZ3fjg!49BE_CbALdvdEn84h2xVkzoTVoqIoe2OP5VB5afrMUnq=
s5G8ac0tKrZNiJ4BftTjoDJCVJFRt0D0VFiKRXAo7fx9ya8$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=
v/qpf/99epoints.txt__;!!DZ3fjg!49BE_CbALdvdEn84h2xVkzoTVoqIoe2OP5VB5afrMUnq=
s5G8ac0tKrZNiJ4BftTjoDJCVJFRt0D0VFiKRXAoaqgMoh0$=20

=3D =3D =3D
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