Area Forecast Discussion
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FXUS62 KKEY 061434

Area Forecast Discussion
National Weather Service Key West FL
934 AM EST Tue Dec 6 2016

A large upper level low is nearly stationary over the western Great
Lakes this morning. An associated short wave is moving northeast over
the Tennessee Valley with a trailing, and weakening shear zone over
the eastern Gulf of Mexico. Several other short waves are diving out
of the Pacific Northwest on the back side of the upper low bringing
cold Artic air through the Northern Tier States. Due to the
weakening pressure gradient over the area, winds are decreasing
across the Keys and South Florida, from west to east.

With the support for the shear zone, "decaying front", to our north,
and the high pressure aloft, have delayed showers until after
midnight for the island chain. winds will continue to decrease
through the day becoming light and variable overnight through
Wednesday night. The Artic airmass mentioned above will help drive a
a trough across the Colorado Front Range Wednesday night, with a
developing short wave pushing across the Mid Atlantic Thursday night.
A cold front will drop across the northern Gulf of Mexico Thursday
evening heading for the Florida Keys. The front will arrive after
midnight Friday, but the real cooler and drier air will pull up short
of the Keys Friday afternoon. Surface high pressure will bridge over
the front resulting in winds increasing quickly Thursday night and
Friday with only a brief reprieve from above normal temperatures and
dew points. Another trough will cross the eastern United States on
Monday with a weakening front dragging behind and over the northern
Gulf of Mexico Monday afternoon. This front will fall apart north of
the Keys, with a weakening pressure gradient and decreasing winds
Monday afternoon. Expect perturbations in the pressure field to
induce peaks and lulls for winds Monday night through Tuesday.


high pressure to our east will continue to weaken as a front decays
to our north today. Winds will decrease from west to east through
tonight becoming light and variable by Wednesday morning. Will keep
cautionary headlines for the far eastern Florida Straits for one more
forecast cycle, but remove all mention of advisory. A cold front will
approach South Florida and the Keys Thursday night with strong high
pressure building across the eastern United States. Expect fresh to
strong breezes to spread over the entire Keys Coastal Waters Friday
and extend through at least early Sunday.


VFR conditions are expected to prevail the remainder of today and
into this evening, with the main operational issue the south wind
near 180 degrees 10 knots that is expected to become south-southwest
during the early afternoon hours...likely 17-19Z. Winds are expected
to become southwest and decrease to near 5 knots after sunset. While
vicinity showers are indicated later this afternoon at both Key West
and Marathon, there is the possibility of pushing back the arrival
of vicinity showers to later in the evening.


On this date in Keys Weather History, 2013. the low temperature at
the Key West International Airport was 77 degrees. This set the daily
record warm minimum temperature in Key West, which may be broken
today. Temperature records for Key West date back to 1872.




Data Collection......Chesser

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