Special Marine Warning 21, NWS Key West, FL

788 
FZUS72 KKEY 161410
MWSKEY

Marine Weather Statement
National Weather Service Key West FL
910 AM EST Sun Jan 16 2022

GMZ033-034-055-075-161500-
/O.CON.KKEY.MA.W.0021.000000T0000Z-220116T1500Z/
910 AM EST Sun Jan 16 2022

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 1000 AM EST...

For the following areas...
Straits of Florida from Halfmoon Shoal to 20 nm west of Dry Tortugas
out 60 nm...
Gulf of Mexico including Dry Tortugas and Rebecca Shoal Channel...
Gulf Waters from East Cape Sable to Chokoloskee 20 to 60 nm out and
beyond 5 fathoms...

At 908 AM EST, strong thunderstorms with possible waterspouts were
located along a line extending from 10 nm west of L Tower to Dry
Tortugas to 20 nm south of Tortugas Ecological Reserve South, moving 
east at 35 knots. An additional thunderstorm was located 5 nm 
southwest of the T Tower, moving northeast at 25 knots. 

HAZARD...Waterspouts and wind gusts 45 knots or greater.

SOURCE...National Weather Service Meteorologist.

IMPACT...Waterspouts can quickly form and capsize boats, cause 
         considerable damage to vessels and create suddenly higher 
         waves. Expect wind gusts in excess of 45 knots, suddenly 
         higher waves, frequent lightning, and heavy downpours.

Locations in the warning include...
Rebecca Shoal Light, Dry Tortugas, Pulaski Shoal Light, Tortugas
Ecological Reserve South, Dry Tortugas Light, Tortugas Ecological
Reserve North and T Tower.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare for wind gusts in excess of 34 knots, steep and fast-building
seas, frequent lightning strikes, and blinding downpours. Stay low or
go below, and make sure all on board are wearing life jackets.

&&

LAT...LON 2461 8328 2495 8318 2502 8313 2503 8232
      2546 8262 2559 8193 2557 8190 2461 8249
      2359 8277 2366 8310 2382 8324 2410 8329
TIME...MOT...LOC 1408Z 281DEG 33KT 2533 8265 2466 8285 2410 8317 

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

$$

JR

Area Forecast Discussion...UPDATED
National Weather Service Key West FL
624 AM EST Sun Jan 16 2022

.UPDATE...
Southerly winds have continued to increase across the Keys and
surrounding waters during the past couple of hours, with the peak
wind gust reaching 31 kt at Key West during the past hour. With
the 1000 foot winds from the 12Z sounding coming in at 31 kt, and
the latest HRRR guidance showing a further increase in winds
during the next few hours ahead of the approaching cold front and
squall line, have posted a Wind Advisory for all of the Florida
Keys through 4 PM this afternoon. No other changes.

&&

.Prev Discussion... /issued 425 AM EST Sun Jan 16 2022/

.DISCUSSION...
Windy, warm and dry conditions prevail across the Florida Keys on
this early Sunday morning. A few brief and light showers have
developed during the night along the northward moving Cuban land
breeze boundary, but these have not persisted for any length of
time. More substantial scattered showers and isolated
thunderstorms are moving across the southeastern Gulf of Mexico.
Along the island chain, temperatures are hovering in the mid 70s,
with dewpoints in the mid 60s, and winds from the south around 20
mph with higher gusts. Surface analysis depicts low pressure
centered over southern Alabama, with a sharp cold front extending
southward through the eastern Gulf of Mexico to the Yucatan
Peninsula. This front is being driven quickly eastward by an
intense closed low aloft, which is clearly evident on water vapor
imagery across southern Mississippi. IR satellite imagery shows
convection increasing during the last couple of hours just ahead
of the front, with this activity currently located about 160 miles
west of the Dry Tortugas and about 230 miles west of Key West. The
00Z Key West sounding sampled a dry and stable airmass at that
time, with a strong inversion based near 6000 feet and PW of 0.92
inches. MIMIC-TPW imagery shows PWs near one inch still over the
Keys at this time, with moisture increasing sharply from just west
of the Dry Tortugas ahead of the advancing front.

The main forecast focus remains the potential for strong to
locally severe thunderstorms later today, as the cold front and
likely an associated squall line moves rapidly eastward through
the Keys. The relative lack of shower development out ahead of the
front may allow for a few hours of at least partial sunshine this
morning, and with temps starting out in the mid 70s it will not
take much insolation to push temps into the upper 70s or perhaps
even to near 80 degrees. Dewpoints are still forecast to creep
into the upper 60s by midday. We should have ample deep layer
shear in the 30-40 kt range within a fairly unidirectional wind
profile, so sufficient instability remains the question,
especially given the amount of modification that must occur from
the dry and stable airmass we observed with the Saturday evening
sounding. CAM guidance continues to indicate that a decent squall
line will move quickly from west to east across our area from late
morning through the mid afternoon hours, and the Storm Prediction
Center still has the Keys in a Marginal Risk for severe weather
today, with damaging wind gusts appearing to be the primary
threat. All of the above considerations yield no significant
change to the existing forecast.

The front will push southeast of the Keys and into the Straits by
early this evening, with any lingering showers during the evening
dwindling to a few light sprinkles after midnight. Only modestly
cooler temps are expected behind this front, with the following
high pressure being of Pacific rather than Canadian origin. Breezy
conditions will continue tonight into Monday morning. Dry and
cool weather will prevail through much of this week, with the
coolest temps occurring Monday night when most locations should
drop into the mid to upper 50s. After cool highs only near 70 on
Tuesday, we expect a slow warming trend with temps returning to
near normal for the later part of the week.

Guidance has trended stronger but also diverged somewhat with the
next cold front late this week. The 00Z ECMWF is more amplified
with low pressure developing in the eastern Gulf and a fairly
strong front moving through the Keys Friday night, while the 00Z
GFS shows a flatter pattern aloft and somewhat weaker front,
although with similar timing. While rain chances with that front
remain uncertain, there is increasing likelihood that the front
will pass through the Keys, bringing breezy and slightly cooler
weather as we head into next weekend.

&&

.MARINE...
Overnight observations show strong southerly winds across the Keys
coastal waters. Strong south to southwest breezes this morning will
shift to the west to northwest this afternoon, as a squall line
and intense cold front moves quickly eastward through the Keys.
Small Craft Advisories are posted for all waters. Fresh
northwest breezes will prevail behind the front tonight into
Monday, becoming moderate from the north to northeast Monday
night. Small Craft Advisories will be needed tonight into Monday
for most of the area, with advisory conditions due to large seas
lingering across the Straits and offshore Gulf waters into Monday
night. Breezes will veer toward the east and relax Tuesday
through Wednesday, as weak high pressure moves across the
Southeastern states and into the western Atlantic.

&&

.AVIATION...
Moderate south to southwest breezes will prevail at both EYW and MTH
early this morning ahead of an approaching vigorous squall line.
VCTS has been included at 17Z and 19Z for EYW and MTH respectively.
A TEMPO group will likely be included in the next routine update
for EYW as the event nears. Possible impacts include TEMPO IFR
VIS, IFR-MVFR CIGS, and convective wind gusts from the west at 35
knots or greater. MVFR stratocumulus will follow before starting
to lift in the evening hours.

&&

.CLIMATE...
On this day in Keys weather history in 1877, the daily record
high temperature of 90F was recorded at the Key West International
Airport. This is also the warmest temperature ever recorded in
January, and the only time the temperature has ever reached 90F in
Key West between the dates of November 18th and April 4th.

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...Wind Advisory until 4 PM EST this afternoon for FLZ076>078.

GM...Small Craft Advisory for GMZ031>035-042>044-052>055-072>075.

&&

Public/Marine/Fire...Jacobson
Aviation/Nowcasts....JAM
Data Acquisition.....MRR

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Hazardous Weather Outlook...UPDATED
National Weather Service Key West FL
618 AM EST Sun Jan 16 2022

FLZ076>078-GMZ031>035-042>044-052>055-072>075-171100-
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-
618 AM EST Sun Jan 16 2022

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

.DAY ONE...TODAY AND TONIGHT

An intense cold front will move through the Keys during the
afternoon, with a squall line expected just ahead of or along the
front. Strong to isolated severe thunderstorms will be possible,
with the highest potential for severe weather from midday through
the afternoon hours. Wind gusts of 45 to 55 mph and frequent
lightning will be the primary threat, with the potential for
isolated damaging wind gusts of 60 mph or greater or a brief
tornado.

A Wind Advisory is posted for all of the Florida Keys today. South
to southwest winds of 20 to 30 mph with frequent gusts over 35 mph
will shift to the west this afternoon as the cold front moves
through.

Small Craft Advisories are in effect for all Keys coastal waters
today and tonight, due to strong south to southwest winds of 20 to
25 knots, shifting to the west to northwest behind the cold
front. Seas will build to 7 to 9 feet in the western sections of
the nearshore Gulf waters and Hawk Channel, and to 7 to 11 feet in
the offshore Gulf waters and the Straits of Florida.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

Small Craft Advisories will be needed across the offshore Gulf
waters and Straits of Florida on Monday due to seas of 7 feet or
higher. These conditions may linger across parts of the area into
Monday evening.

From Tuesday through Saturday, no hazardous weather is expected at
this time.

.SPOTTER INFORMATION STATEMENT...

Law enforcement agencies, emergency management officials, storm
spotters, and other interested parties should monitor this
situation and take appropriate action should severe weather
threaten your area. Spotters should report any severe weather
observed to the National Weather Service office in Key West.