Special Marine Warning 47, NWS Key West, FL

Area Forecast Discussion
National Weather Service Key West FL
218 PM EDT Tue Jun 15 2021

.DISCUSSION...
A fairly high amplitude trough is sitting along the east
coast, and is currently part of a blocking pattern with a large
ridge sitting over the southwestern states. Because of this, the
trough will be slow to degrade and move off towards the northeast.
There is a large swath of moisture through the depth of the
troposphere to the east of the trough along the eastern seaboard
which extends across south Florida and the Keys and into the Gulf
of Mexico. This will remain over the area likely through Thursday
morning, and will result in above normal precipitation chances as
well as thunderstorms. As the influence of the trough along the
east coast slowly begins to wane, the Atlantic ridge axis will
begin to lift north of the Keys and over south Florida. This will
keep the area in averaged southerly boundary flow through
Wednesday night. By Thursday afternoon, dry air associated with
the Saharan Layer will begin to filter into the area from the
south, aided by circulation around the forecast low in the
western Gulf. This should limit convective potential
substantially through the weekend, although the broken cirrus
deck that has plagued the area for the past few days will remain,
as a result of upper level outflow from whatever develops (if
anything does) in the western Gulf. By Saturday morning, the
broken cirrus deck should decrease rapidly. After a prolonged dry
period Thursday night through Monday, the Atlantic ridge will
again build back into the area. With this, rain chances will
return to near climatological averages by Monday night into
Tuesday.

&&

.MARINE...
Gentle southeasterly breezes will persist over all the Florida
Keys coastal waters through tomorrow afternoon. However, showers
and thunderstorms over the waters are likely, and can occur at
anytime. If storms do develop, the movement will likely be
generally towards the north. Beginning Thursday evening, rain
chances will diminish dramatically, and drier than normal
conditions will persist through the weekend with only isolated
showers expected. As well, moderate to fresh southeasterly breezes
will begin tomorrow evening and persist out of the east to
southeast through the weekend.

&&

.AVIATION...
Prevailing conditions will be VFR at both the Key West and
Marathon terminals overnight and into tomorrow afternoon. However,
showers and thunderstorms are possible during this time, and could
result in temporary MVFR or even IFR conditions. This is most
likely at the Key West terminal, and thunderstorms could impact
the terminal later today. Tomorrow, showers and thunderstorms are
also likely to impact either terminal at some point during the
day. Surface winds overnight and tomorrow will be out of the
southeast near 5 knots, and may be light and variable at times.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  79  87  79  88 / 50 60 40 40
Marathon  80  90  79  90 / 40 50 40 40

&&

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

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

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Hazardous Weather Outlook...RESENT
National Weather Service Key West FL
429 AM EDT Tue Jun 15 2021

FLZ076>078-GMZ031>035-042>044-052>055-072>075-161000-
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-
429 AM EDT Tue Jun 15 2021

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

.DAY ONE...TODAY AND TONIGHT

Isolated thunderstorms today may increase to scattered
thunderstorms this evening and tonight. The primary thunderstorm
hazards include dangerous cloud to surface lightning strikes and
possibly a few wind gusts to near 40 mph, especially this
evening.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

Isolated thunderstorms are possible Wednesday through Monday. The
primary thunderstorm hazards will be cloud to surface lightning
strikes and locally gusty winds.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.