Area Forecast Discussion
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FXUS62 KKEY 241857
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
257 PM EDT Wed May 24 2017

.DISCUSSION...
.CURRENTLY...
Skies are partly to mostly sunny with temperatures in the upper
80s and uncomfortable dewpoint readings in the upper 70s along the
island chain. Meanwhile, local radars are only detecting a few
showers on the distant waters beyond 20 nm south of the Florida
Keys. Surface wise, a western Atlantic ridge lies in the Straits
of Florida with an intensifying low pressure system (995 mb)
located over the Tennessee/Kentucky border with an associated
trough reaching southward into the south central Gulf of Mexico.
Across our marine district, south winds range from 19 and 20 knots
at Molasses Reef Light and Smith Shoal Light respectively to 14
knots at Pulaski Shoal Light.

&&

.SHORT TERM...(Tonight through Saturday night)
An unusually deep mid and upper level trough in the central Gulf
of Mexico will migrate eastward and across the Sunshine State by
Thursday morning, before lifting northward into Friday.
Thereafter, a deep tropospheric western Atlantic ridge near the
island of Cuba will lift northward into our region. But until
then, a gradually moistening and destabilizing airmass should
allow at least some shower and thunderstorm activity to move
northward from the island of cuba this evening and early tonight.
After midnight, low level confluence combined with weak mid and
upper ascent from the aforementioned trough aloft should be the
impetus for another round of rainfall. For Thursday, despite a
decelerating low and mid level flow, plenty of moisture within a
southwest steering flow should allow additional showers and
thunderstorms to redevelop in the afternoon and continue into
Thursday evening for drier air filters in. With that said, will
maintain likely pops tonight through Thursday evening with low
chance pops thereafter.

&&

.LONG TERM...(Sunday through Wednesday)
A western Atlantic ridge will hold firm across the southern half
of the Florida peninsula before slowly retreating eastward by late
Wednesday. Without any discernible mid and upper level ascent, low
level moisture within a light to gentle easterly wind should
provide enough moisture for sub synoptic forcing. Hence, isolated
20 percent pops with high temperatures in the upper 80s and
overnight lows in the upper 70s will be retained through the
period.

&&

.MARINE...
Due to increasing winds in varying degrees from east to west, A
Small Craft Advisory will be in effect for all Keys coastal waters
tonight. In addition, winds and seas will be even higher near
developing showers and possible thunderstorms. Fresh to strong
southwest winds will persist Thursday morning before abating
appreciably from west to east during the afternoon. Thereafter,
outside of any showers or thunderstorms, light to gentle winds
will prevail into this weekend.

&&

.AVIATION...
South to southwest crosswinds will gust to 20 knots at the EYW and
MTH terminals this afternoon and evening. Before sunset, we expect
showers and thunderstorms streaming to the north to northeast from
the Atlantic waters, which could affect both terminals later
tonight. Thus, periods of MVFR CIGS and IFR VIS could be possible
with convective wind gusts reaching 25 to 30 knots.

&&

.CLIMATE...
In 1937, the daily record rainfall of 3.15 inches of rainfall was
recorded in Key West. Rainfall records have been kept since 1871.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  78  84  78  87 / 70 70 70 30
Marathon  79  88  77  90 / 70 70 70 30

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory for GMZ031>035-042>044-052>055-072>075.

&&

$$

Public/Marine/Fire...APA
Aviation/Nowcasts....KN
Data Collection......Vickery

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