Special Marine Warning 233, NWS Key West, FL

Area Forecast Discussion
National Weather Service Key West FL
1032 PM EDT Fri Oct 8 2021

.DISCUSSION...
Currently - A trough aloft is amplifying as it digs southeastward
across the eastern Gulf of Mexico and Florida. Associated upper
level support is contributing to lower level troughing over the
extreme southeastern United States and a band of showers and
thunderstorms across Central Florida. Closer to home, weak lower
level ridging remains across the Keys and the surface pressure
gradient is supporting light southeasterly breezes. This
evening's sounding indicated fairly dry air and some inhibition
layer centered around 800 mb. This has kept showers in check
through the evening.

Short Term Update - The upper level trough will continue to dig
southeastwards through the overnight period with the trough axis
draped across the extreme southeastern Gulf of Mexico and Central
Florida by morning. A swath of increased lower level moisture
associated with the upper trough will continue to press
southeastward but will remain north of our area overnight. The
lower level ridge and associated lower level dry and stabilizing
layer will hold on across our area. This along with surface flow
being light and primarily out of the southeast should ensure rain
chances will remain slight overnight.

The story becomes much more complicated beyond tonight. The upper
trough will continue to swing southeastward across Florida and
step into the Atlantic late Saturday. This trough will cut off
through the remainder of the weekend and wobble southwestward
across South Florida and the Keys. While the best upper level
support appears to sneak east of our area, the local environment
will experience increasing deep layered moisture and increasing
cyclonic flow above the surface. The surface flow will remain
light as weak troughing/low develops over South Florida. Given
this, rain chances are expected to rise considerably through the
weekend. With that said, uncertainty remains high.

&&

.MARINE...
A weak split ridge across South Florida will maintain light mostly
southeasterly breezes across Keys waters through the overnight
period. Only minor adjustments made in the evening marine update.

&&

.AVIATION...
VFR conditions will prevail at both MTH and EYW through tomorrow
night. There is a lot of uncertainty in regards to the development
of showers tomorrow. Some guidance has shower activity beginning
tomorrow afternoon, while other guidance leaves us high and dry
through tomorrow evening. There is also the possibility of a reverse
cloud line developing during a short window tomorrow afternoon. Due
to lower confidence in the short-term forecast, have opted not to
include any mention of showers in the TAF at this time. Winds will
be out of the east to southeast at 5 to 8 knots tonight, then are
expected to become variable around 5 knots tomorrow morning.

&&

.CLIMATE...
On this day in 1996, the daily record rainfall of 2.36" was
recorded in Key West. Rainfall records date back to 1871.

&&

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

&&

Public/Marine/Fire...11
Aviation/Nowcasts....NB

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Hazardous Weather Outlook...UPDATED
National Weather Service Key West FL
804 AM EDT Fri Oct 8 2021

FLZ076>078-GMZ031>035-042>044-052>055-072>075-091100-
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-
804 AM EDT Fri Oct 8 2021

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

.DAY ONE...TODAY AND TONIGHT

Isolated thunderstorms are expected. The primary thunderstorm
hazard will be lightning strikes.

The Key West tide gauge has measured high tides about a half foot
above the predicted tides for the past several days. The high
tides tonight through Sunday night will be an inch or two higher
than yesterday's high tide. Coastal Flood Statements may be
required for portions of the Florida Keys.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

Saturday through Sunday night, scattered thunderstorms are
expected. The primary thunderstorm hazards will include lightning
strikes and locally heavy downpours.

Monday through Tuesday night, isolated thunderstorms are
expected. The primary thunderstorms hazard will be lightning
strikes.

Wednesday through Thursday night, scattered thunderstorms are
expected. The primary thunderstorm hazard will be lightning
strikes.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

Kasper/CLR