Special Marine Warning 41, NWS Key West, FL

561 
FZUS72 KKEY 132313
MWSKEY

Marine Weather Statement
National Weather Service Key West FL
713 PM EDT Thu May 13 2021

GMZ031-042-052-132322-
/O.CAN.KKEY.MA.W.0041.000000T0000Z-210513T2345Z/
713 PM EDT Thu May 13 2021

...THE SPECIAL MARINE WARNING IS CANCELLED...

The affected areas were... 
Hawk Channel and Straits of Florida from Ocean Reef to Craig Key out
20 nm...
Florida Bay including Barnes Sound, Blackwater Sound, and Buttonwood
Sound...

The thunderstorms over the waters adjacent to the Upper Keys have 
weakened, therefore the Special Marine Warning has been cancelled.

LAT...LON 2534 8025 2532 8026 2515 7999 2499 8020
      2528 8041 2529 8039 2528 8036 2529 8034
      2528 8033 2532 8029 2533 8030 2533 8028
      2535 8027 2535 8026
TIME...MOT...LOC 2309Z 320DEG 12KT 2526 8018 2519 8030 

$$

11

Area Forecast Discussion
National Weather Service Key West FL
315 PM EDT Thu May 13 2021

.DISCUSSION...
Water vapor imagery highlights broadly cyclonic flow across the
CONUS with westerlies well displaced to the south into the Gulf of
Mexico. The 12Z mid to upper level heights fell significantly on
the KKEY RAOB. Surface observations and visibile satellite
imagery place a diffuse surface trough across South Florida,
although a fair amount of mid to high level cloud cover has
limited the intensity of the sea breezes, and hence convection.

Light northwest to north breezes prevail across the island chain.
Skies are mostly sunny and the KBYX radar is echo free.
Temperatures are in the mid to upper 80s with dewpoints a few
degrees lower than this morning, ranging from 70 to 75.

.FORECASTS...
The surface trough will sag southward overnight, then lay solidly
across the Keys on Friday. Before then, there are signals for a
north to northeast wind surge around midnight tonight. Is this a
a short- lived gradient associated with the trough shedding from
South Florida, a relic cold pool, or a propagating outflow
boundary? It should be noted, low- level speed convergence would
be rather robust if this scenario plays out. On Friday and Friday
night, the statistical guidance is mixed on rain chances, although
low-level steering, limited inhibition, and plentiful moisture
would favor building cumulus along the island chain in the
afternoon, and another round of storms diving southwest off the
Mainland in the evening. Building breezes and a meager shot of
modified- Continental air will lower rain chances Saturday through
Sunday night, although the boisterous boundary layer breezes will
not reduce rain chances to nil.

The extended forecast will feature rich and strong tropical
breezes, no deep layer inhibition, and episodes of veering,
cyclonic coupling. Although not a typical rainy season pattern,
long range statistical QPF estimates highlight a period of wetter
than normal weather from Monday night through at least Wednesday.

&&

.MARINE...
Small Craft Should Exercise Caution for increasing winds across
the Gulf side waters and the deeper waters of the southeastern
Gulf of Mexico due to north winds 15 to 20 knots. From synopsis,
a weak trough will linger across South Florida and the Florida
Keys tonight and Friday. A short lived north to northeast blow is
expected around and after midnight, followed by gentle northeast
breezes on Friday. High pressure will build from the eastern
United States into the western North Atlantic Friday night and
Saturday, with freshening easterly breezes starting Friday night.
The strongest breezes over the next five days will be Saturday
night through Sunday night.

&&

.AVIATION...
VFR conditions will prevail at both terminals through 12z Friday
morning. There is a slight chance for a few showers to develop
overnight in the vicinity of either terminal, although confidence
is too low to include in the TAFs at this time. Chances for
showers and thunderstorms will increase shortly after sunrise
Friday morning. Have included a broad mention of VCSH in the TAFs
at this time after 12z, with the expectation that specific windows
of impacts will be included in later TAF amendments and TEMPOs.
Light and variable winds will become northwest to north this
evening, then eventually northeast and increase to 10 to 13 knots
after midnight, decreasing to 8 to 10 knots near sunrise.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  79  86  77  85 / 20 40 40 20
Marathon  78  87  76  86 / 30 50 50 30

&&

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

Public/Marine/Fire...CLR
Aviation/Nowcasts....BT
Data Acquisition.....KR

Visit us on the web at weather.gov/key

Follow us on Facebook and Twitter at:
www.facebook.com/nwskeywest
www.twitter.com/nwskeywest

Hazardous Weather Outlook
National Weather Service Key West FL
422 AM EDT Thu May 13 2021

FLZ076>078-GMZ031>035-042>044-052>055-072>075-140830-
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-
422 AM EDT Thu May 13 2021

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

.DAY ONE...TODAY AND TONIGHT

Conditions are favorable for a cloud line could develop later
this morning. In addition, light and variable flow may support
waterspouts with said cloud lines.

Otherwise, isolated thunderstorms will be possible this
afternoon, especially across the Upper Keys as convection comes
off the mainland. The primary hazards will be lightning strikes
and locally gusty winds.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY
Isolated thunderstorms will be possible Friday through Saturday.
The primary hazards will be lightning strikes and locally gusty
winds.

A Small Craft Advisory may be required for most or all of the Keys
coastal waters from Saturday night through Monday night, due to
east winds near 20 knots, and seas building to 7 feet in the
Florida Straits.

Otherwise, no hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.