Area Forecast Discussion
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FXUS62 KKEY 291355

Area Forecast Discussion
National Weather Service Key West FL
955 AM EDT FRI JUL 29 2016

.DISCUSSION...In the Middle and upper levels (700-200 mb), latest
available ir imagery overlaid with model streamline analysis as of
800 am detail the axis of a deep and warm core positively tilted
middle and upper level ridge oriented across the Western Atlantic
from about 35 North 65 West southwestwards to near Tampa. Upstream of
the Keys, the axis of a TUTT (Tropical Upper Tropospheric Trough) is
located from 27 North 60 West south southwestward to across the Mona
passage into the Southern Caribbean Sea, and migrating quickly

.CURRENTLY...At the surface and in the lower to middle levels
(Surface to 700 mb), latest IR imagery overlaid with available
marine and land surface observations and analysis as of 800 am detail
a typically weak surface ridge across Central Florida to north of
the Bahamas. Across the tropics, there are two waves across the
Eastern Atlantic well east of 50 West. Two other tropical waves west
of 50 degrees are at a low latitude, with the first approaching
Barbados. The next inverted trough upstream of the Keys is north of
Hispaniola. Finally, the axis of a departing inverted trough/weak
wave now well west of the Keys over the SE Gulf of Mexico. As a
result, the morning sounding illustrated a gentle east to southeast
flow from the surface to about 500 mb and was typically moist with
PWAT at 1.82 inches, with fresh to strong easterlies increasing
above 500 mb.

.SHORT TERM...Rest of today and tonight, forecast sounding continue
with indications of some middle level drying this afternoon, but they
allow for a more favorable cloudline direction across the lower and
middle keys, with 06z GFS forecast soundings indicating PWAT near
1.75 inches and ECMWF at 1.50. May make a last minute decision to
increase rain chances to 30 over the islands. Nevertheless drying
likely to ensue again by a few hours after sunset, with little storm
motion for leftover boundaries to collide.


.MARINE...Light to gentle southeast breezes will continue through the
weekend. Mariners in the immediate nearshore waters should be on the
lookout for waterspouts later this afternoon and evening. Waterspouts
tend to form along the edge of long dark flat cloud bases. If one is
cited in close proximity, perform evasive action by moving away from
it at a 90 degree angle asap.

Prevailing VFR conditions are expected at the EYW and MTH through
the end of the forecast period, with light east southeast breezes
and clouds FEW to SCT, based near 2,000 feet. The potential exists
for a shower to impact either terminal, but confidence in timing and
occurrence remains low, thus not included in the TAF at this time.


Month to date, 3.68 inches of rain has fallen at the Key West
International Airport, which is just 0.37 inches above normal. The
yearly rainfall total in Key West now stands at 16.47 inches, which
is 1.58 inches below normal. Rainfall records in Key West date back
to 1871.


.KEY Watches/Warnings/Advisories...


Data Collection......Vickery

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