Special Marine Warning 166, NWS Key West, FL

Area Forecast Discussion
National Weather Service Key West FL
621 AM EDT Sun Aug 15 2021

.DISCUSSION...
Remnants of Fred are almost fully out of our area this morning.
BYX radar and infrared satellite imagery has shown quite the
blossom in convection along the eastern periphery of what appears
to be the mid level circulation. Convection in the far western
waters overnight has been quite impressive with likely gusts
nearing 40 knots at times. Fred will likely re- obtain Tropical
Storm status as it continues to move northwest across the Gulf of
Mexico and away from the Florida Keys coastal waters. As Fred
pulls away from the area, moisture will linger along with some
confluence. Given that the main source of convergence and moisture
has lifted out of the area, do not really see why model guidance
still shows such high PoPs. As such, will keep PoPs relatively
modest at 40 percent for today. Windy conditions persist across
the lower Keys and then quickly falls off as you go east up the
Florida Keys. These winds will come down after sunrise.

Thereafter, Atlantic ridge will build back westward into the
southeastern U.S.. This will allow our winds to back to the east
starting this evening and persisting through the mid-week. Winds
are expected to lull significantly on Tuesday a spoke of the ridge
builds across Florida. Deep layered moisture will gradually
decrease, returning the Keys to a more seasonable mid summer time
environment with decent CAPE and weak inhibition. Will maintain
low to mid chance pops through the first half of the week. Expect
near normal temperatures with dew points in the mid 70s.

After the rather brief break from From the departed Fred, Tropical
Storm Grace will continue to race westward into the Caribbean Sea
brush Puerto Rico late Sunday and pass over Hispaniola from early
Monday through early Tuesday. Grace should then continue over Cuba
through Tuesday and into the Florida Straits on Wednesday. Due to
the substantial land interaction, the current National Hurricane
Center forecast brings Grace into our area as a Tropical Storm.
On the official forecast track, tropical storm conditions will be
possible for the Florida Keys and surrounding waters beginning
Wednesday and ending on Thursday. With all that said, uncertainty
remains large and Grace could behave much as Fred did due to the
land interaction. Stay tuned.

&&

.MARINE...
A sharp gradient in winds is seen by this mornings marine
observations. Winds have come down to 10 to 15 knots across the
central and eastern waters, while still 20 to 25 knots across the
western waters. As such, Small Craft Advisories will continue this
morning for the western waters until the wind gradient associated
with Fred sufficiently lifts northwest out of our waters.
Thereafter, Atlantic ridge will begin to take control of Keys
weather and gentle to moderate southeasterly breezes and a more
normal distribution of showers and thunderstorms will prevail.
Winds will likely fall to their minimum on Tuesday as a spoke of
the ridge builds across the Florida peninsula. This break will be
short lived however as Tropical Storm Grace, currently racing
westward towards the Windward Islands is expected to reach the
Florida Straits on Wednesday and then out into the Gulf of Mexico
on Thursday. While confidence remains quite low due to track
uncertainties and possibly significant interaction with the
Greater Antilles and Cuba, tropical storm conditions could once
again return to Keys waters for a day or two beginning around mid
week.

&&

.AVIATION...
VFR conditions will prevail at both island terminals through the TAF
period. A few showers have been passing near MTH so have kept VCSH
there, but have removed it from EYW for the time being. VCSH is re-
introduced around mid-morning at EYW, however, there is still some
uncertainty regarding timing and location of any shower activity.
Surface winds will be out of the southeast at 15 to 20 knots with
gusts near 25 knots at EYW, decreasing to 8 to 12 knots with gusts
near 15 knots. At MTH, winds will be southeast from 8 to 12 knots,
with gusts of 15 to 20 knots through the morning.

&&

.CLIMATE...
On this day in 1964, the daily record high temperature of 98 was
last recorded in Marathon. This also ties for the warmest
temperature ever recorded in the month of August for the Marathon
area. Temperature records at Marathon date back to 1950.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  89  81  91  82 / 40 30 30 20
Marathon  88  81  88  81 / 40 30 30 30

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory for GMZ033>035-044-054-055-074-075.

&&

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

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Hazardous Weather Outlook
National Weather Service Key West FL
634 AM EDT Sun Aug 15 2021

FLZ076>078-GMZ031>035-042>044-052>055-072>075-161045-
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-
634 AM EDT Sun Aug 15 2021

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

.DAY ONE...TODAY AND TONIGHT

Remnants of Fred will track northwest away from the Dry Tortugas
this morning, then potentially strengthen into a tropical storm as
it enters the southeastern Gulf of Mexico. Hazards for the
Florida Keys will be hazardous marine conditions, possible
waterspouts. Thundery squalls will be capable of localized wind
gusts near 40 knots and lightning strikes. Conditions will improve
later this morning. Elsewhere, lingering showers and isolated
thunderstorms will occasionally pass across the Florida Keys
today.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

Isolated thunderstorms will be possible Monday through Friday.
The primary thunderstorm hazards will be lightning strikes.

The long range forecast for Tropical Storm Grace indicates a
persistent path to the west-northwest through the Greater
Antilles, then the Bahamas, and possibly into portions of the
Florida Keys and South Florida in four to five days. It is still
too early to discuss all of the possible impacts, although
confidence in another round of locally heavy rainfall is
increasing.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE KEY WEST FL
717 AM EDT SUN AUG 15 2021

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

0637 AM     MARINE TSTM WIND 4 SE TEATABLE KEY       24.85N 80.62W
08/15/2021  M50 MPH          GMZ042             FL   MESONET

            A SOUTHEAST WIND GUST OF 43 KTS, OR 50 MPH, WAS RECORDED
            BY THE WEATHERFLOW MESONET SITE AT ALLIGATOR REEF LIGHT
            AT 637 AM EDT.

&&

JAM