Flood in Florida, December 29, 2024

Area Forecast Discussion
National Weather Service Key West FL
1022 AM EST Sun Dec 29 2024

...New DISCUSSION, MARINE, AVIATION...

.DISCUSSION...
Issued at 1015 AM EST Sun Dec 29 2024

A very active weather morning for the Florida Keys, particularly
for the coastal waters north of the Island Chain. An expansive
cluster of strong showers and thunderstorms, with a few embedded
stronger supercells, have been detected since the early morning
hours. This is the region in closest proximity to a shortwave
trough pivoting to the northeast to east over the northern Gulf,
with the best resulting upper-level divergence. The 12z sounding
at KEY sampled daily record breaking tropospheric integrated
precipitable water, along with an impressive Supercell Composite
Parameter of around 5, indicative of a favorable environment for
right-moving supercells. The surface synoptic map places a
deepening area of low pressure over the Tennessee Valley, with
high pressure in the western North Atlantic. As is often the case
in this evolving scenario, winds are over producing relative to
all available numerical weather prediction guidance. As a result,
Small Craft Advisories had to be expanded to cover all Keys marine
zones earlier this morning.

For the rest of today, the aforementioned shortwave trough will
continue to pivot northeastward. Forecast soundings after 00z
indicate substantial mid- and upper-level drying. Surface winds
will collapse, as the Keys tight pressure gradient is quickly
replaced by a near-col region. In summary, a few more hours of
scattered strong storms and breezy to windy conditions, before
conditions improve substantially for the Keys by late afternoon or
evening. Hang in there, Florida Keys.

&&

.MARINE...
Issued at 1015 AM EST Sun Dec 29 2024

A Small Craft Advisory is in effect for all Florida Keys marine
zones. Strong thunderstorms will continue across the Keys coastal
waters through at least the early afternoon. These storms will be
capable of producing wind gusts over 35 knots, small hail, and a
few waterspouts. From synopsis, accelerated flow rounding an
Atlantic high and feeding into a deepening low lifting out of the
southeastern United States continues to produce strong east to
southeast breezes. Breezes will will slacken later this afternoon,
with the pressure gradient relaxing. Breezes will further slacken
tonight, as the Atlantic high weakens and is shoved further out
to sea. Expect shower coverage to rapidly diminish by late
afternoon and early evening. Light and possibly variable winds are
becoming increasingly likely for the early part of next week,
before the next cold frontal passage around mid week.

&&

.AVIATION...
(15Z TAFS)
Issued at 1015 AM EST Sun Dec 29 2024

Weather over the island terminals will oscillate between MVFR and
VFR conditions today as vicinity showers reduce CIGs and VIS. A
cluster of thunderstorms was located north of the EYW and MTH, but
at present the strongest cells are staying offshore. Vicinity
thunderstorms are possible, and TEMPOs will be issued ahead of time
should stronger cells near the terminals. Shower coverage, near
surface winds, and threat of thunder will diminish after sunset and
veer southerly in the second half of the TAF period.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  80  72  79  72 /  60  30  10  10
Marathon  79  72  79  72 /  60  30  10  10

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory until 11 AM EST this morning for GMZ031>035-
     042>044-052>055-072>075.

&&

Public/Marine/Fire...BT
Aviation/Nowcasts....AJP
Data Acquisition.....AJP/BT

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Hazardous Weather Outlook
National Weather Service Key West FL
553 AM EST Sun Dec 29 2024

FLZ076>078-GMZ031>035-042>044-052>055-072>075-301100-
Monroe Upper Keys-Monroe Middle Keys-Monroe Lower Keys-
Florida Bay including Barnes Sound, Blackwater Sound, and
Buttonwood Sound-
Bayside and Gulf side from Craig Key to west end of Seven Mile
Bridge-
Gulf waters from East Cape Sable to Chokoloskee 20 to 60 NM out
and beyond 5 fathoms-
Gulf of Mexico including Dry Tortugas and Rebecca Shoal Channel-
Gulf of Mexico from west end of Seven Mile Bridge to Halfmoon
Shoal out to 5 Fathoms-
Hawk Channel from Ocean Reef to Craig Key out to the reef-
Hawk Channel from Craig Key to west end of Seven Mile Bridge out
to the reef-
Hawk Channel from west end of Seven Mile Bridge to Halfmoon Shoal
out to the reef-
Straits of Florida from Ocean Reef to Craig Key out 20 NM-
Straits of Florida from Craig Key to west end of Seven Mile
Bridge out 20 NM-
Straits of Florida from west end of Seven Mile Bridge to south of
Halfmoon Shoal out 20 NM-
Straits of Florida from Halfmoon Shoal to 20 NM west of Dry
Tortugas out 20 NM-
Straits of Florida from Ocean Reef to Craig Key 20 to 60 NM out-
Straits of Florida from Craig Key to west end of Seven Mile
Bridge 20 to 60 NM out-
Straits of Florida from west end of Seven Mile Bridge to south of
Halfmoon Shoal 20 to 60 NM out-
Straits of Florida from Halfmoon Shoal to 20 NM west of Dry
Tortugas 20 to 60 NM out-
553 AM EST Sun Dec 29 2024

This Hazardous Weather Outlook is for the Florida Keys and
adjacent coastal waters.

.DAY ONE...Today and tonight.

A few thunderstorms will remain possible today due to an
unsettled weather pattern. The main hazards will be a few
lightning strikes, blinding downpours, and locally gusty winds.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

No hazardous weather expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Preliminary Local Storm Report
National Weather Service Key West FL
924 AM EST Sun Dec 29 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0900 AM     Non-Tstm Wnd Gst Duck Key                24.77N 80.91W
12/29/2024  M42 MPH          Monroe             FL   Mesonet

            A southeast to south wind gust of 37 knots,
            or 42 mph, was measured by the Weatherstem
            mesonet station located in Duck Key.

&&

BT

Preliminary Local Storm Report
National Weather Service Key West FL
1125 AM EST Sun Dec 29 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1030 AM     Tstm Wnd Gst     Duck Key                24.77N 80.91W
12/29/2024  M40 MPH          Monroe             FL   Mesonet

            A southeast to south wind gust of 35 knots,
            or 40 mph, was measured by the Weatherstem
            mesonet station located in Duck Key.

&&

BT

Preliminary Local Storm Report
National Weather Service Key West FL
1224 PM EST Sun Dec 29 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1206 PM     Tstm Wnd Gst     5 SSE Islamorada        24.85N 80.62W
12/29/2024  M39 MPH          GMZ052             FL   Mesonet

            An easterly wind gust of 34 knots, or 39
            mph, from a thunderstorm was measured by the
            XALG Alligator Reef Light WeatherFlow
            mesonet station.

&&

BT