Area Forecast Discussion
Issued by NWS
FXUS62 KKEY 280714
Area Forecast Discussion
National Weather Service Key West FL
314 AM EDT THU JUL 28 2016
Surface analysis and satellite observations show a weak tropical
wave moving westward over Cuba. The axis of the wave extends to just
north of Cayo Romano, central Cuba, and is showing signs of
additional lifting over the Florida Straits at this hour. Key West
radar has isolated showers with a few embedded thunderstorms
traveling northwest at 10 to 15 knots. Winds are out of the southeast
near 10 knots along the Keys Island Chain, and near 15 knots with
higher gusts at the marine reporting stations surrounding the Keys.
.SHORT TERM (Today through Saturday)...
The weak tropical wave mentioned above will quickly destabilize the
environment that is already moisture rich at around 95 percent of
normal precipitable water. MIMIC TPW suggests this will increase with
the approach of the wave as well. With have chance of showers and
thunderstorms for today and tonight. This looks good as of this
forecast cycle mainly due to the limited northern extent of the wave
axis. However, tonight we may have to increase rain chances if there
is any mid level support that develops similar to the Tuesday night.
Saturday will be a bit drier in the back side of the wave with large
scale deep layer subsidence.
.LONG TERM (Sunday through Wednesday)...
The next in a series of weak waves will be entering the Caribbean on
Saturday, then nearing the eastern Florida Straits by early Sunday.
Model guidance would suggest that this wave will be slightly more
robust that the previous set, but will keep chance of showers and
thunderstorms for Saturday night through Sunday night until we have a
consensus in the guidance. Winds will surge again Saturday night
through Sunday night at least. Thereafter, expect a return to a more
normal forecast for late summer in the Florida Keys with a chance of
showers and thunderstorms, highs near 90 and lows near 80.
Small craft should exercise caution this morning on all Keys waters
with the exception of Florida Bay and the Bay Side waters through at
least early this afternoon. Recent trends suggest that winds are
beginning to relax around the Keys and on the Florida Straits. These
breezes will remain out of the east to southeast near 15 knots north
of the Island Chain, and 15 to 20 knots to the south early, then
decrease through the afternoon. The next surge in winds will arrive
Saturday night and extend through Sunday. A cautionary statement may
be required Saturday night through Sunday night.
The best chance of showers/thunderstorms impacting the terminals
will be during the morning hours today. Will place VCTS in the TAFs
from 11-17Z. Possible impacts would last 1-2 hours and would include
lightning...wind gusts of 25-30 knots...visibilities of 1-3SM...and
MVFR ceilings. Will keep the forecasts dry after 18Z. Outside of
shower activity expect east to southeast winds 10-13 knots with
occasional gusts 15-20 knots.
On this date in Keys Weather History, 1916, 7.14 inches of rain fell
in Key West. This set the daily record rainfall and, for the month of
July, is the wettest day ever. Rainfall records for Key West date
back to 1871.
.PRELIMINARY POINT TEMPS/POPS...
Key West 88 82 89 82 / 40 40 30 20
Marathon 89 82 92 82 / 40 40 30 20
GM...Small Craft Advisory until 11 AM EDT this morning for GMZ052>055-
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