Special Marine Warning 4, NWS Key West, FL

Area Forecast Discussion
National Weather Service Key West FL
1043 PM EDT Sat Apr 10 2021

.DISCUSSION...
Currently - An Atlantic high is centered well northeast of the
Bahamas and extends a broad ridge southwestward across South
Florida and Cuba. The lower level ridge is aligned across and
northeast of the Bahamas. Meanwhile, troughing aloft is spilling
east southeastwards into our area and was earlier responsible for
a strong squall line that sped south and southeastwards through
the Gulf of Mexico and approaching our area. This evenings
sounding indicated surface based CAPE of around 3100, a good
amount of dry air aloft and only a sliver of very low level
inhibition. The increased convergence across our area along with
winds quickly veering from east southeast to southwest through the
lowest 100 mb has resulted in an eruption of scattered to
numerous showers with embedded thunderstorms across the Keys and
surrounding waters. At this time, the strongest activity is
located on our western most waters.

Short Term Update - In the near term, shower and thunderstorm
activity is expected to increase near the island chain. This is
due to the squeeze play between the synoptic southeasterlies and
the northeasterly wind surge associated with the gulf squall.
With that said, all mesoscale models suggest the vast majority of
the heaviest and most concentrated activity will remain west of
the Keys. There is precedence for this, particularly that the
showers in and around the Keys will more likely than not drop its
own outflow boundaries stabilizing the environment. With all this
in mind, will raise pops to high chance and increase thunderstorm
coverage. In wake of the shower and thunderstorm activity in the
near term, winds will gradually relax and shift back to light
southerlies, more representative of the synoptic flow. Outside of
rain cooled areas, overnight lows will be in the mid 70s with dew
points lingering in the lower 70s.

&&

.MARINE...
A ridge to our northeast as a trough swings through the
southeastern United States. Gentle to moderate southeasterly
breezes will relax and shift southerly as the ridge shifts east
southeasterly. An active weather pattern is in place and showers
and thunderstorms have developed, with the strongest and most
concentrated activity located over our western most gulf and
Atlantic waters. This activity should remain to our west, there
will also be showers and a few thunderstorms nearer the island
chain.

&&

.AVIATION...
Showers and thunderstorms developing in an around the Florida Keys
this evening may deliver a brief spell of sub VFR conditions at
the island terminals. Surface winds will generally be light to
gentle out of the southeast, shifting south. With that said,
convective activity near and not so near the terminals may produce
short term large perturbations in both wind speed and direction.

&&

.CLIMATE...

&&

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

&&

Public/Marine/Fire...11
Aviation/Nowcasts....SDR
Data Acquisition.....DR

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Hazardous Weather Outlook
National Weather Service Key West FL
420 AM EDT Sat Apr 10 2021

FLZ076>078-GMZ031>035-042>044-052>055-072>075-111000-
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-
420 AM EDT Sat Apr 10 2021

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

.DAY ONE...TODAY AND TONIGHT

For today, no hazardous weather is expected at this time.

Tonight, isolated thunderstorms will be possible across the
Florida Keys and the surrounding coastal waters. The primary
thunderstorm hazards will be cloud to surface lightning strikes
and locally gusty winds.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

Isolated thunderstorms will be possible across the Florida Keys
and the surrounding coastal waters from Sunday afternoon through
Monday. The primary thunderstorm hazards will be cloud to surface
lightning strikes and locally gusty winds. A few of the storms
could become strong to marginally severe Sunday night.

Otherwise, no hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.