Area Forecast Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
FXUS62 KKEY 240836

Area Forecast Discussion
National Weather Service Key West FL
436 AM EDT Wed May 24 2017

Currently - A deep layered amplified trough is moving into the
eastern United States, with its tail end dipping into the Gulf of
Mexico. As a result, pressures are falling in the Mississippi
Valley. Meanwhile, a broad surface ridge extends across Cuba.
Gentle to moderate southerly breezes across the Keys is bringing
in warm and humid conditions. Temperatures are hovering near 80
with dew points in the upper 70s. Outside a bit of inhibition down
low, there is ample cape above, but still some mid level dry air.
Shower activity has been limited this morning most shower and
thunderstorm activity has remained outside of the forecast area.

Forecast - A wet pattern is shaping up for the Florida Keys for
the next couple of days. The previously mentioned trough will
edge eastward across the Gulf of Mexico today, into the Atlantic
on Thursday. Accelerating moist confluent low level flow, along
with some mid level cooling and support aloft will result in an
increasingly favorable environment for rounds of shower and
thunderstorm development. Some of this activity could be strong
and fast moving with the steering flow increasing to 25 to 30
knots this afternoon. Helicity however is expected to remain
fairly low. The wettest time periods will be from late this
afternoon to early Thursday night. There is significant
uncertainty on exactly when winds will strengthen. However all
guidance suggests that winds will trend sharply upwards tonight,
becoming windy as the gradient is pinched between the migrating
trough and the ridge to our south. Winds will relax significantly
late Thursday as the trough lifts out and leaving a very lack
luster gradient across the Keys. Light and variable winds Friday
morning will gradually pick up gently out of the east to southeast
by the weekend as ridging resumes is normal location across the
Florida Peninsula.


A trough moving eastwards across the Gulf of Mexico will result in
an uptrend in winds as well as shower and thunderstorm activity.
Expect windy conditions to develop tonight, then slacken rapidly
late Thursday as the trough moves across the Florida Peninsula
then lifts out. A caution will be raised today for the Bay and
deep gulf waters and an advisory will likely be required for all
Keys waters tonight and Thursday.


South to southwest crosswinds will gust to 20 knots at the EYW and
MTH terminals through the forecast period. VFR will predominate
until this afternoon, when scattered showers and thunderstorms will
develop over Cuba and the southeastern Gulf of Mexico. The Cuban
storms will move quickly north-northeast through the Straits of
Florida, while the convection over the Gulf will work slowly
southeast. Thus, periods of MVFR CIGS and IFR VIS appear possible at
both terminals this evening and overnight. Convective wind gusts
will reach 25 to 30 knots.


Key West  87  77  84  78 / 30 70 70 70
Marathon  91  78  88  77 / 30 70 70 70





Visit us on the web at

Follow us on Facebook and Twitter at: is the U.S. government's official web portal to all federal, state and local government web resources and services.