Special Marine Warning 36, NWS Key West, FL

593 
FZUS72 KKEY 212005
MWSKEY

Marine Weather Statement
National Weather Service Key West FL
405 PM EDT Wed Apr 21 2021

GMZ055-075-212030-
/O.CON.KKEY.MA.W.0036.000000T0000Z-210421T2030Z/
405 PM EDT Wed Apr 21 2021

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 430 PM EDT...

For the following areas...
Straits of Florida from Halfmoon Shoal to 20 nm west of Dry Tortugas
out 60 nm...

At 405 PM EDT, a strong thunderstorm was located 18 nm southeast of
Tortugas Ecological Reserve South, moving east at 15 knots.

HAZARD...Wind gusts 34 knots or greater.

SOURCE...National Weather Service Meteorologist.

IMPACT...Expect wind gusts in excess of 34 knots, suddenly higher 
         waves, frequent lightning, and heavy downpours.

The strong thunderstorm will remain over mainly open waters.

LAT...LON 2434 8288 2386 8291 2388 8314 2435 8311
TIME...MOT...LOC 2005Z 265DEG 15KT 2415 8296 

HAIL...0.00IN
WIND...>34KTS

$$

LIW

175 
FZUS72 KKEY 212029
MWSKEY

Marine Weather Statement
National Weather Service Key West FL
429 PM EDT Wed Apr 21 2021

GMZ055-075-212039-
/O.EXP.KKEY.MA.W.0036.000000T0000Z-210421T2030Z/
429 PM EDT Wed Apr 21 2021

...THE SPECIAL MARINE WARNING WILL EXPIRE AT 430 PM EDT...

The affected areas were... 
Straits of Florida from Halfmoon Shoal to 20 nm west of Dry Tortugas
out 60 nm...

The thunderstorm has moved out of the warned area.

LAT...LON 2434 8288 2386 8291 2388 8314 2435 8311
TIME...MOT...LOC 2029Z 291DEG 12KT 2413 8290 

$$

LIW

Area Forecast Discussion
National Weather Service Key West FL
1107 AM EDT Wed Apr 21 2021

.DISCUSSION...
Currently - An old frontal boundary draped across South Florida
and the southeastern Gulf of Mexico is associated with a band of
showers with embedded thunderstorms. Thus far, this convective
activity has remained beyond our gulf zones. However this
boundary is sagging slowly southeastward, shoved by high pressure
building down through the Gulf of Mexico. Ahead of this boundary,
winds across the Keys are light to gentle and variable in
direction. This is despite the western flank of the Atlantic ridge
extending across Cuba. The weak flow in and around the Keys is
confluent, with squeezing taking place between the ridge to our
south and a mid latitude trough over and east of the Florida
Peninsula. As a result, a band or two of showers and a few
thunderstorms have developed across the Upper Keys this morning.

Short Term Update - The previously mentioned high pressure will
force the old frontal boundary through the Keys late this
afternoon and evening. Ahead of this, winds will gradually firm up
out of the west then shift northwest to north as the old front is
flushed through. This mornings soundings and forecast soundings
indicate virtually no inhibition with above normal PWATs near 2
inches. Given this, there will be a chance for showers and a few
thunderstorms. There will be ample time and sufficient sunshine,
under fairly weak flow, to push temperatures up into the mid to
upper 80s early this afternoon. Dew points will hover in the mid
70s.

&&

.MARINE...
An Atlantic ridge across Cuba and an old frontal boundary across
the southeastern Gulf of Mexico will result in light winds
gradually firming up out of the west early this afternoon. High
pressure building down the Gulf of Mexico will flush the old
frontal zone into Keys waters later this afternoon and evening
resulting in winds gradually shifting northwest to north then
strengthen a bit further. There will be a chance for showers and
isolated thunderstorms. Minor adjustments made in the first period
in the morning marine update.

&&

.AVIATION...
VFR conditions will prevail at both island terminals through 00z
this evening. Scattered showers and a few thunderstorms associated
with a frontal passage will push through the Keys from west to east
after 18z today. Only a period of VCSH is currently included in the
TAF at this time due to the uncertainty in timing and evolution, but
TEMPOs and amendments are expected later this afternoon. Light and
variable winds will become southwest to west early this afternoon,
then become west to northwest and increase to 8 to 12 knots.

&&

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

&&

Public/Marine/Fire...11
Aviation/Nowcasts....BT
Data Acquisition.....JAM

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Hazardous Weather Outlook
National Weather Service Key West FL
431 AM EDT Wed Apr 21 2021

FLZ076>078-GMZ031>035-042>044-052>055-072>075-220845-
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-
431 AM EDT Wed Apr 21 2021

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

.DAY ONE...TODAY AND TONIGHT

A few thunderstorms are possible along the Florida Keys and the
adjacent coastal waters.

The primary thunderstorm hazard will be cloud to surface lightning
strikes.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE KEY WEST FL
156 PM EDT WED APR 21 2021

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

1158 AM     WATER SPOUT      2 S CHANNEL 5 BRIDGE    24.81N 80.77W
04/21/2021                   GMZ043             FL   PUBLIC

            MULTIPLE WATERSPOUTS WERE OBSERVED BY A LOCAL RESIDENT
            JUST OFF THE SOUTHEASTERN COAST OF LAYTON, FL AT 1158 AM
            EDT. ONE OF THEM HAD A VISIBLE SPRAY RING WHILE THE OTHER
            TWO HAD FUNNELS BUT WERE NOT OBSERVED AT GROUND LEVEL.

&&

JAM