Area Forecast Discussion
Issued by NWS
FXUS62 KKEY 301950
Area Forecast Discussion
National Weather Service Key West FL
350 PM EDT Thu Mar 30 2017
.DISCUSSION...In the middle and upper levels,(700-200 mb), latest
available model streamline analysis overlaid on top of satelitte
imagery as of 200 pm depict a middle and upper level low pressure
system over Iowa trailing a trough deep into South Texas. A 75 to
100 knot southwesterly jet rounds the base of the deep trough and
moves NEward towards South Florida and the Keys. Very dry air in
place within this weakly cyclonic flow moving across the Keys,
with embedded impulses evident north win the flow over the
At the surface and in the lower to middle levels(Surface to 700
mb), Latest satelitte imagery overlaid with marine and land
surface observations and analysis as of 200 pm, detail a
developing low pressure system located NW of Springfield IL,
moving NE and swinging a cold front to the Western Gulf of Mexico.
As a result, breezy to windy conditions have developed this
afternoon across the Florida Keys and surrounding waters, with the
aforementioned deep dry air squelching any rain showers given the
lower level confluence.
.CURRENTLY...As of 300 pm, skies are mostly sunny across the
islands and adjoining waters. Temperatures are in the middle 80s
with dewpoints in the upper 60s. C-MAN stations along the Florida
Reef are registering SE winds averaging 15 to 20 knots along the
Florida Reef, and near 15 knots in Florida Bay. This is after
several hours of near 20 knots from late morning till now.
.SHORT TERM...Tonight thru Sunday, Weather conditions will be
benign, with the surface front now approaching the Keys this
afternoon basically stalling and dissipating late tonight and
tomorrow, as the parent low zips northeastwards up into the Great
Lakes and Northeast states. Winds will remain breezy thru the
evening and near breezy overnight, as they veer into a southerly
direction. These southerly winds are expected for the first half
of the day on Friday before becoming light and variable as a week
pressure pattern ensues Friday night thru Saturday. Weak ridging
begins to form north of the Keys by Saturday night and Sunday with
light to moderate winds on Sunday. No measurable chances for
showers expected thu this period. The hottest day will be Friday
with south to southwest winds allowing temperatures into the
upper 80s. Highs in the mid 80s for Saturday and Sunday will feel
hot given weaker winds. Lows between 70 and 75 are expected.
.EXTENDED...Sunday night through Thursday, Mid and upper
disturbances will continue to move across the CONUS for Sunday
Night thru Tuesday, with some middle level cooling and instability
moving overhead associated with a decent trough progged to move
across the Lower Mississippi and Tennessee Valleys Monday thru
Tuesday. Best chance for showers is still low, and will occur on
Monday night when the disturbance passes our longitude, with a
slight chance for showers Sunday night and Monday(20%) and for
Tuesday(20%). High temperatures in the mid 80s, with lows only
falling into the mid 70s, outside of any showers that do manage to
move over. After Tuesday, mainly surface ridging is to the north
but with slightly elevated moisture in the boundary layer, kept
dime pops thru the rest of the periods.
.MARINE...SCA will continue for the Florida Straits this evening,
with Caution across Hawk Channel ans well as the offshore Gulf
waters and around the Channels. Winds and seas will let down by
late tonight. No headlines or advisories expected again until
Sunday night thru Monday night.
.AVIATION...VFR will prevail at the EYW and MTH terminals through
the forecast period. Gusty southeast crosswinds will abate at
the terminals by 21Z, only to return for a few hours Friday
morning. Rain chances for either terminal remain near nil.
.PRELIMINARY POINT TEMPS/POPS...
Key West 74 84 74 84 / - - - -
Marathon 73 87 74 87 / - - - -
GM...Small Craft Advisory tonight for GMZ055-072>075.
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