Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 181423

Area Forecast Discussion
National Weather Service Miami FL
Issued by National Weather Service Key West FL
923 AM EST Wed Jan 18 2017

.UPDATE...Much weaker pressure pattern this morning than as of
late, with broad surface ridging over South Florida. Wind
direction and magnitude across available South Florida platforms
range from light and variable to southeast to south aoa 5 to 10
mph. Forecast only required removal of transitional wording in
today period. No other changes necessary on this cycle.


.PREV DISCUSSION... /issued 644 AM EST Wed Jan 18 2017/

For the short term, terminal KAPF could have 4-6 mile visibility
restrictions through 13-14z with lingering early morning fog.
Otherwise, VFR conditions should prevail through tonight. Cant
rule out some visibility restrictions late tonight at KAPF and
KTMB, but confidence is too low to include with 12z issuance. By
mid- morning, calm winds will become SE at 5 to 10 KT, except at
KAPF where Gulf Breeze will bring SW winds by noon. Winds will
calm again this evening.

PREV DISCUSSION... /issued 302 AM EST Wed Jan 18 2017/



As of 300 AM EST...High pressure remains anchored to the northeast
of the Bahamas, with upper-level ridging aloft. The region remained
virtually precip-free, outside of a very light Atlantic streamer off
Palm Beach county. For the rest of tonight, dry weather will
prevail, but cannot rule out a rogue sprinkle or two associated with
any streamer. Patchy fog will be possible across portions of the
interior towards daybreak.

Today, the high pressure will gradually weaken during the day today
and shift slightly west, with a light south/southeast flow across
the region. A strong subsidence inversion around 850 hPa will help
to suppress cloud development today, with dry weather and mostly
sunny skies expected. Temperatures will continue to run around 5
degrees above normal for January, with highs reaching into the lower
80s for most areas.


Dry and pleasant weather will continue through the short term period
as high pressure and upper-level ridging aloft remain anchored over
the region. With the subsidence inversion in place, skies will
continue to remain mostly sunny for most areas through the short
term period. Patchy fog will again be possible Wednesday night in
the interior. The flow will begin to shift more southerly Friday but
remain light. Temperatures will continue to run about 5 degrees
above normal with highs generally in the lower 80s and lows in the
upper 50s to upper 60s, coldest in the interior.


Long range model guidance continues to be in fairly good agreement
with the long term pattern, which will feature southerly flow and a
breakdown of the upper-level ridging aloft. Surface high pressure
initially anchored over the region will gradually shift eastward of
the Bahamas by Sunday. Dry and pleasant weather will continue to
prevail through the weekend as southerly flow slowly advects low-
level moisture back into the region as PWATs rise above 1.75 inches.

While it will continue to remain quiet across South Florida through
much of the weekend, the synoptic pattern upstream will become quite
active as vigorous upper-level energy ejecting out of the lower
Rockies helps form a potent, and deep 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 upper-level trough, a strong cold front will push
across South Florida sometime Monday, likely bringing a period of
gusty widespread showers and thunderstorms. Plenty of moisture and
sufficient instability will be out ahead of this front, and coupled
with strong dynamics and shear associated with the front, strong to
perhaps severe thunderstorms with the front cannot be ruled out and
will need to continue to be monitored closely over the upcoming days.

Temperatures will be above normal during the weekend, trending
towards normal early next week along and behind the frontal passage.

Good boating conditions and dry weather will exist across the local
waters heading into the weekend, with southeast flow less than 15
knots becoming more southerly Friday. Seas will be 4 feet or less
heading into the weekend. Boating conditions across the region will
begin to deteriorate by the late weekend as a strong cold front
approaches the region.

VFR conditions should prevail during the TAF period. Cant
completely rule out some brief fog restrictions at Naples late
tonight, so placed 6SM group during this time. Generally calm
winds overnight will become SE at 5-10 KT during the day, then
become calm again tonight. Naples likely to have a SWly Gulf
breeze during peak heating.

West Palm Beach  82  63  81  63 /   0   0   0  10
Fort Lauderdale  81  66  80  66 /   0   0   0   0
Miami            81  66  81  66 /   0   0   0   0
Naples           80  60  79  62 /   0   0   0  10



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