Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 190845
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
345 AM EST Thu Jan 19 2017

.DISCUSSION...

NEAR AND SHORT TERM /TODAY THROUGH SATURDAY NIGHT/...

As of 345 AM EST...High pressure remains in place across the
region, with upper-level ridging aloft. With high pressure
overhead, winds have decoupled across the mainland, with patchy
fog possible in the interior through daybreak. After any fog
dissipates, a dry day is expected with mostly sunny skies.

High pressure will continue to dominate through Saturday night, with
quiet and dry weather with mostly sunny skies and light winds.
Temperatures will be above normal by about 5 degrees through the
period.

LONG TERM /SUNDAY THROUGH WEDNESDAY/...

Strong cold front may bring some strong storms to South Florida late
Sunday into early Monday...

After a stretch of quiet weather, the pattern will become more
active for the first half of the long term period. Long range model
guidance continues to be in good agreement with the long term
synoptic pattern, which will become very active to end the weekend
and begin next week. On Sunday, vigorous upper-level energy will
eject out of the lower Rockies and into the Gulf states to help form
a potent, and deep closed off upper-level trough. This upper-level
trough will feature plenty of potent shortwave energy that will help
dig the trough axis will into the Gulf of Mexico, with a core of
potentially sub 540 dam 1000-500 hPa thicknesses reaching well into
the Deep South. Ahead of this system, the southerly flow will begin
to increase and help to advect lower level moisture back into the
region as dewpoints surge into the upper 60s and possibly lower 70s.

Ahead of this upper-level trough, a strong cold front will push
across South Florida, with the latest model guidance continuing to
show an earlier timing trend, now sometime Sunday night into early
Monday morning. In terms of dynamics associated with the front, this
front will be the strongest of the season thus far, likely bringing
a period of gusty widespread showers and thunderstorms. Strong
thunderstorms cannot be ruled out with the frontal passage, with the
threat of severe storms still remaining murky at this time. Outside
of any gusty winds associated with the showers/storms, the gradient
flow will be quite strong, with winds approaching advisory levels
over the mainland. Continue to monitor the forecast closely over the
upcoming days.

Behind the frontal passage, high pressure will build across the
region bringing a return to pleasant and dry weather. Temperatures
will be near to slightly below normal, with highs in the mid and
upper 70s and lows in the mid 50s to mid 60s.

&&

.MARINE...
Hazardous marine conditions developing late this weekend and into
early next week ahead of strong cold front...

Good boating conditions and dry weather will exist across the local
waters through the first half of the weekend, with southeast flow
less than 15 knots becoming more southerly Friday. Seas will be 4
feet or less through the first half of the weekend.

Beginning Saturday winds will increase to around 15 knots ahead of a
developing and approaching cold front. Hazardous marine conditions
are expected to begin late Saturday and into Sunday as southerly
winds ahead of the cold front continue to increase to 20-25 knots.
As the front crosses the region Sunday night into early Monday
morning, gale force sustained winds and gusts will be possible as
the flow shifts southwest to west. Seas will rapidly build during
this period as well, especially over the Gulf, where wave heights
may exceed 15 feet in the offshore waters. In the Atlantic, wave
heights could also exceed 10 feet. Hazardous marine conditions look
to continue well into the middle of next week before high pressure
leads to a reduction in winds and seas.

&&

.BEACH FORECAST...
Favorable beach conditions will prevail into Saturday with a light
flow regime. Beginning late Saturday, rip current risk will
increase, especially for the Gulf beaches as a strong cold front
approaches the region. Dangerous surf, beach erosion, and minor
coastal flooding will also be possible along the Gulf coast late
Sunday and into early next week associated with strong onshore
southwest to westerly flow as the cold front moves across the
region.

&&

.AVIATION...
VFR conditions will prevail. Cant rule out some fog restrictions
in Naples early this morning, so have placed 6SM BR from 8-14z.
Calm winds will become onshore at 5-8 KT by late morning, then
calm again in the evening.

&&

.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach  81  62  82  65 /   0   0   0   0
Fort Lauderdale  79  66  81  68 /   0   0   0  10
Miami            81  66  82  68 /   0   0   0  10
Naples           79  62  80  64 /   0   0   0  10

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
GM...None.
&&

DISCUSSION...92/IRL
MARINE...92/IRL
AVIATION...23/SK
BEACH FORECAST...92/IRL






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