Special Marine Warning 247, NWS Key West, FL

Area Forecast Discussion
National Weather Service Key West FL
1036 PM EDT Sun Oct 24 2021

.DISCUSSION...
The mean layer ridge centered over the Yucatan is squashed from
the broad belt of westerlies racing across the northern Gulf of
Mexico. A diffuse warm frontal boundary stretches west from the
northern Bahamas to the central Gulf. The Florida Keys sit on the
cusp of anticyclonic flow to the south, and weak cyclonic flow to
the north.

Southeast surface winds average 5 to 10 knots at the marine
observation platforms. Temperatures are near 80 with dewpoints in
the mid 70s. The island chain is rain-free. Infrared imagery
highlights several mature thunderstorms moving north towards the
Dry Tortugas. Based on brightness temperatures, these storms and
the ones to the immediate northwest are the tallest in the CONUS.

The 00Z KKEY RAOB sampled 2.24" of PW and a deep veering profile.
There was a subtle Cuban shadow signal noted down low, but on the
whole, a sounding supportive of deep convection. Steering flow
should veer to the southwest over the next several hours, sending
the remnants of the convection near and south of the Tortugas to
the east towards the island chain. We will maintain the 50%
chances for the overnight period, well above normal, but below the
bullish MOS guidance, which has been overdone for several days. No
changes needed or planned.

&&

.MARINE...
There are no watches, warnings, or advisories currently in effect
for the coastal waters of the Florida Keys. A weak, broad dome of
high pressure will remain entrenched across the Atlantic, with
the associated ridge axis extending across Florida. Light to
gentle breezes are expected through Monday, and drier conditions
are anticipated Tuesday and Wednesday. A frontal boundary will
approach Florida as early as Wednesday night resulting in
freshening southwesterly breezes.

&&

.AVIATION...
VFR conditions will prevail for both EYW and MTH into tomorrow
morning. A line of showers and thunderstorms is approaching from
the southwest Straits of Florida. VCSH was included at both
terminals to account for its arrival and will be modified as this
activity develops. Surface winds will be generally out of the
southeast becoming southwest between 2 to 8 knots.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  78  85  78  86 / 50 40 30 20
Marathon  77  86  78  87 / 50 40 30 20

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&

Public/Marine/Fire...CLR
Aviation/Nowcasts....JAM
Data Acquisition.....SMS

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Hazardous Weather Outlook
National Weather Service Key West FL
603 AM EDT Sun Oct 24 2021

FLZ076>078-GMZ031>035-042>044-052>055-072>075-251015-
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-
603 AM EDT Sun Oct 24 2021

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

.DAY ONE...TODAY AND TONIGHT

Isolated thunderstorms are possible today and tonight. The primary
thunderstorm hazards will be cloud to surface lightning strikes
and locally heavy rainfall.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

Isolated thunderstorms will be possible Monday and Thursday
through Saturday. The primary thunderstorm hazards will be
possible cloud to surface lightning strikes and locally heavy
rainfall.

Winds are expected to freshen beginning Wednesday night. While
there remains uncertainty with timing, Cautions and Advisories
will begin expanding across Keys waters as early as Thursday or
Thursday night.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.