FOUS30 KWBC 170635
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
135 AM EST Fri Jan 17 2025

Day 1
Valid 12Z Fri Jan 17 2025 - 12Z Sat Jan 18 2025

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

The latest CAM guidance suite has some signals for heavy rainfall
in the vicinity of the Florida Keys along a quasi-stationary
frontal boundary during the day Friday, and the model consensus is
for most of this convection to remain over the Florida Straits and
the western Bahamas. Although some of these cells may affect
coastal areas of South Florida, the coverage and rainfall rates are
low enough to preclude any risk areas at this time.

Hamrick


Day 2
Valid 12Z Sat Jan 18 2025 - 12Z Sun Jan 19 2025

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

Chenard


Day 3
Valid 12Z Sun Jan 19 2025 - 12Z Mon Jan 20 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS FAR
SOUTHERN GEORGIA INTO NORTH FLORIDA...

1930z Update: Forecast still looks on track. Not seeing anything
in the 12z guidance to suggest any changes are needed to the
inherited Marginal risk at this time.

Chenard

...Previous Discussion...

PW values expected to rise to 2 to 2.5 standard deviations above
the mean Saturday into early Sunday along and ahead of the arctic
frontal boundary pushing across the northeast Gulf into the
Southeast and North Florida. The axis of strong low level west
south westerly flow along and ahead of the arctic front will slow
for a period late Saturday into early Sunday as mid level height
falls dive into the base of the broad vortex across eastern North
America. This will support potential for training of precip areas
along and just to the south of the arctic front across far southern
Georgia into North Florida. The non NCEP models...EC..CMC...CMC
GEM and UKMET...are showing a more organized axis of heavy rainfall
potential than the GFS and NAM. WPC qpf is leaning more toward the
non-NCEP guidance given the anomalous PW values and potential for
a period of training. The expected axis of heavy rains is forecast
across regions that have seen increases in relative soil moisture
over the past week from recent heavy rains that have stretched from
the central Gulf Coast into the FL Panhandle and North Florida.
Still, FFG values remain high, with the forecast additional
rainfall amounts of 1-2" likely only resulting in isolated runoff
issues.


Oravec


Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=
v/qpf/94epoints.txt__;!!DZ3fjg!57SZna1d5qkF_PWNc2WNsI3p7M9UBM_nDcedLm0ja9dW=
atKbyaYvPtikqsVkD2B7GuKMhtMLQonTpbP3pQ0-qxPJZ6c$=20
Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=
v/qpf/98epoints.txt__;!!DZ3fjg!57SZna1d5qkF_PWNc2WNsI3p7M9UBM_nDcedLm0ja9dW=
atKbyaYvPtikqsVkD2B7GuKMhtMLQonTpbP3pQ0-bxibYiU$=20
Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=
v/qpf/99epoints.txt__;!!DZ3fjg!57SZna1d5qkF_PWNc2WNsI3p7M9UBM_nDcedLm0ja9dW=
atKbyaYvPtikqsVkD2B7GuKMhtMLQonTpbP3pQ0-6dC7ruA$=20

=3D =3D =3D
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