Area Forecast Discussion
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FXUS62 KKEY 280123

Area Forecast Discussion
National Weather Service Key West FL
923 PM EDT Tue Jun 27 2017

.DISCUSSION...In the middle and upper levels(700-200 mb), latest
available satelitte imagery overlaid with model streamline
analysis as of 800 pm depicts a well defined cold core trough
aligned across the Eastern CONUS from Eastern Canada down to its
base over Georgia. South of that, a regional scale middle and
upper level ridge is centered 26.5 N, 74 W. And to the immediate
west of this feature and over South Florida, the Florida Keys, and
the Straits, there is almost zero flow here. And latest GOES
16-Water vapor imagery also illustrates a very dry middle and
upper level airmass in place overhead.

At the surface and in the lower to middle levels(Surface to 700
mb), latest marine and land observations and analysis as of 800 pm
details a frontal boundary that has reached Northern Florida, but
is rapidly losing its identity this evening. South of that, a
surface ridge extends from the Central Bahamas west to smack dab
near the Keys island Chain. Key West radar is registering a few
showers which popped in a presunset cloudline that developed
because VWP indicated that the surface to 500 mb winds backed
last minute near the islands. As such there was a report of a
funnel cloud along the reef just southwest of Big Pine Key. The
00Z evening sounding illustrated light to gentle northeast winds
from just off the surface to 850 mb, then gentle to moderate
southwest to west winds above that to 200 mb. Columnar PWAT was
moderate at 1.66 inches.

.CURRENTLY...As of 800 pm, as mentioned before, radar detects a
few showers along a broken cloudline along the reef south of the
Middle and Lower Florida Keys. Temperatures are in the middle to
upper 80s with sweltering middle to upper 70s dewpoints. C-man
stations along the Florida Reef are recording mostly east winds
near 5 knots, and island sensors are registering winds near 5

.SHORT TERM...Overnight, despite leftover boundaries lurking near
the Keys and some boundaries in the Florida Straits, isolated
showers and thunderstorms will have trouble developing on account
of the abundance of low-middle level dry air. Additionally, 0-6 km
storm motion supports little movement of said boundaries. A weak
pressure pattern will allow light to gentle easterlies as local
surface ridging bifurcates on either side of South Florida. Hence,
no changes to the ongoing forecast we have, so will maintain
isolated chances for showers and thunderstorms.


.MARINE...Variable winds near 5 knots, will become light to gentle
and mostly east across much of the entire marine district, with
the only exception being across the outermost Florida Straits,
where winds may be more gentle, like 10 knots, from the northeast
resultant from leftover Cuban land breezes. Bottom line is great
boating conditions expected.


.AVIATION...VFR conditions expected at both the KEYW & KMTH I`ntl
island terminals, with a few-sct cumulus clouds with bases found
aoa FL020.


On this date in Keys Weather History, 1883, a high temperature of
94 degrees was recorded in Key West. This set the daily record
for warmest temperature in Key West for June 27th, a record which
still stands 134 years later. Temperature records for Key West
date back to 1872.




Data Collection......DR

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