Areal Flood Advisory 1, NWS Key West, FL

Area Forecast Discussion
National Weather Service Key West FL
859 PM EDT Mon Apr 19 2021

.DISCUSSION...
A fairly active convective evening over the Florida Keys coastal
waters. Several thunderstorms have developed from cumulus fields
over the Florida Straits and progressed towards the northeast near
20 knots. Storm tops have been just shy of 45 kft, and have been
more organized than a typical pulse thunderstorm scenario. One
thunderstorm north of Key West breifly popped above 50 kft.This
is not surprising since the Key West evening sounding revealed a
good degree of convective instability. Precipitable water values
are up around 2 inches, and the boundary layer from 700mb down is
close to saturation. ML CAPE is approaching 3000 J/kg with
virtually no inhibition. Therefore, any lift from boundaries or
thunderstorm outflow will produce a convective cell. New cells are
now forming well southwest of the Lower Keys - also moving
swiftly towards the northwest. So it would seem that this
convection will last well into the overnight hours.

&&

.MARINE...
Scattered showers and thunderstorms will impact the Keys coastal
and nearshore waters for the remainder of the evening and
overnight. Some of these storms could be strong, producing wind
gusts approaching 34 knots. Storms that do develop will be moving
rapidly towards the northwest, between 20 and 25 knots. Winds will
be generally from the southwest around 10 knots, but can
dramatically shift and strengthen in the vicinity of showers and
storms.

&&

.AVIATION...
Although VFR conditions will generally prevail at both the Key
West and Marathon terminals, passing strong showers and storms can
result in brief periods of MVFR or even IFR conditions, mainly at
the Key West terminal overnight. There is not enough certainty in
the timing and location of the storms as the evening progresses,
so there may be amendments to the terminal forecast as events
unfold.

&&

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

Public/Marine/Fire...Devanas
Aviation/Nowcasts....Devanas
Data Acquisition.....KR

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Hazardous Weather Outlook
National Weather Service Key West FL
447 AM EDT Mon Apr 19 2021

FLZ076>078-GMZ031>035-042>044-052>055-072>075-200900-
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-
447 AM EDT Mon Apr 19 2021

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

.DAY ONE...TODAY AND TONIGHT

Isolated thunderstorms are possible late this afternoon and
tonight. The primary thunderstorm hazards will be cloud to surface
lightning strikes and locally strong gusty winds.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

Isolated thunderstorms are possible on Thursday. The primary
thunderstorm hazard will be cloud to surface lightning strikes.

Otherwise, no hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

APA