Area Forecast Discussion
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FXUS62 KKEY 260846

Area Forecast Discussion
National Weather Service Key West FL
446 AM EDT Wed Sep 26 2018

There has been very little change to the local weather pattern
over the past 24 hours. Mean layer ridging persists over the
western North Atlantic. Last evening`s KKEY RAOB sampled easterly
winds from the SFC to the tropopause. According to SPC`s sounding
climatology page, integrated moisture has fallen to 1.66", which
is a little below normal. The 925 mixing ratio value was below
the 10th percentile. The lack of low level moisture has put the
kibosh on overnight convection, with only a few isolated showers
detected by the KBYX radar at this hour. East to southeast winds
average 10 to 15 knots across the Florida Keys, with temperatures
in the lower to mid 80s. Summer continues across the island chain,
despite evidence of the first cold front moving southeast through
the Mississippi River Valley.

An extended period of deep easterlies is expected across the
Florida Keys. Mean layer ridging over the western North Atlantic
will be occasionally reinforced by continental infusions. Upstream
satellite derived moisture products and forecast soundings
indicate vertical moisture will swing wildly over the next few
days. An undulation in the easterlies will push through late
tonight and early Thursday morning, featuring an increase in rain
chances. Thereafter, 30% rain chances have been retained. Breezy
conditions are expected across the island chain by Sunday, and
will persist through Tuesday.


Small Craft Exercise Caution headlines may be required as early as
Saturday night for portions of the coastal waters of the Florida
Keys as east winds increase to 15 to 20 knots. A Small Craft
Advisory may be required as early as Sunday night as east winds
increase to near 20 knots. From synopsis, a broad ridge axis will
persist north of the Florida Keys today through Saturday.
Moderate east to southeast breezes today through Friday will
freshen Friday night and Saturday as the ridge axis strengthens to
our north.


06Z TAF Discussion.

VFR conditions expected to prevail at EYW and MTH terminals
generally through the forecast period with no big overall changes
with upper ridging to the east of Florida and the surface Atlantic
ridge in place. Isolated showers will be possible off and on tonight
into this morning. Outside of any isolated convection, winds will
remain easterly 8-12 kts, although a few gusts during the afternoon
are possible.


For September 26th, in 2005, the last products were issued from WFO
Key West at the airport, and the move to the new office facility
began. In 1920, the daily record cold high temperature of 78 degrees
was recorded. This is also tied for the coldest high temperature
ever recorded in September. In 2011, the daily record rainfall of
3.36" was recorded. Temperature records at Key West date back to
1872, and precipitation records date back to 1871.


Key West  90  81  90  80 / 30 40 30 30
Marathon  90  81  90  80 / 30 40 30 30




Data Collection......DR

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