Area Forecast Discussion
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FXUS62 KTAE 181342

842 AM EST Tue Nov 18 2014

...A Hard Freeze with Record Cold Temperatures Expected Tonight...

.Near Term [Through Today]...

The 7 am EST regional surface analysis showed the strong cold
front that passed through our forecast area on Monday was across
South FL, with a large high pressure ridge building eastward
across the Gulf Coast states. Vapor imagery and upper air data
showed a large, unusually deep 500 mb trough over the eastern
CONUS. The 7 am EST Tallahassee upper air sounding had the top of
the arctic airmass only at about 2200 ft AGL, so it`s very
shallow. Although the strongest low-level cold air advection has
already occurred, the strong inversion atop the shallow cold air will
limit vertical mixing, helping to keep high temperatures only in
the mid to upper 40s. (That`s 20 to 25 deg below average, despite
plenty of sunshine).



[Through 12Z Wednesday] VFR conditions will prevail through the
period with gusty winds from the north during the day that will
start to settle by around 23Z.


.Prev Discussion [626 AM EST]...

.Short Term [Tonight Through Thursday]...
The massive long wave trough dominating much of North America will
reach its greatest amplitude across the eastern U.S. tonight as one
final short wave moves through its base across the northern Gulf of
Mexico. Meanwhile, the high pressure center of the Arctic air mass
that has arrived in the area will build east to a position near the
AL/GA border by 12Z Wednesday. The position of the high should allow
the boundary layer to decouple with calm winds the result. While
there may be a few high clouds around, they do not figure to have
much moderating affect on temperatures. Forecast lows have not
changed appreciably. We are still looking for most inland areas to
bottom out in the lower 20s with the coldest locations seeing upper
teens. Even FL Panhandle beaches will see several hours of freezing
temperatures. Inland areas will see freeze durations of 10-14 hours.
The hard freeze watch will be upgraded to a warning. This is an
exceptionally cold outbreak for November and we expect to shatter
the daily records for the 19th at TLH (25 degrees in 2008) and AAF
(33 degrees the same year). In fact, if the low of 20 degrees
predicted for TLH is realized, it will be the coldest temperature
ever recorded this early in the season. In this very dry air mass,
temperatures will rebound quickly and will see highs some 10 degrees
higher than today. However, they will still be about 16-17 degrees
below normal. Another widespread freeze is expected Wednesday night.
In fact, parts of the inland FL Big Bend could see another hard
freeze. Max temps on Thursday will jump an other 10 degrees over the
previous day`s numbers and generally be in the mid 60s.

.Long Term [Thursday Night Through Tuesday]...
The warming trend will continue through the weekend as heights rise
and surface high pressure moves off to the east. In fact, we will
actually see temps up around seasonal levels by Sunday. The weekend
will also feature low pressure over TX on Saturday lifting quickly
northeastward to the Great Lakes on Sunday. This system will bring a
front into the region on Sunday with increasing chances for
thunderstorms. Another front will then maintain rain chances into
Monday. Initial indications are that there will be at least some
marginal potential for severe weather with these systems.

With the strong cold front now well south of the forecast area,
blustery north winds are sustained at small craft advisory levels
this morning. While we have seen occasional gusts over 30 kt,
frequent gusts to gale force are no longer anticipated and the
warning will be cancelled. Winds over the nearshore legs will
drop below advisory criteria by this afternoon with the offshore
legs to follow overnight. As high pressure builds east along the
Gulf Coast, winds will continue to subside on Wednesday. Light to
moderate northeast to east winds will then persist across the
Northeast Gulf through the end of the work week. Easterlies may
reach cautionary levels on Saturday.

.Fire Weather...
 A very dry, cold air mass will be in place over the area Tuesday and
Wednesday with gusty winds during the day Tuesday. A red flag
warning remains in effect this afternoon for southeast Alabama for
long durations of relative humidity below 25 percent. A red flag
warning is also now in effect in central and coastal Walton for
relative humidity below 25 percent with 20-foot winds around 15 MPH
and ERC values over 26, as well as in Washington, Bay, Leon, and
Wakulla counties where relative humidity will be below 25 percent
for 4 or more hours and ERC values will be above 37. A fire weather
watch is in effect for tomorrow for all of these counties except
Walton (due to lower wind speeds). Red flag conditions may be
possible Thursday as well. By Friday, moisture will begin to return
to the area before our next cold frontal passage early next week.


Rainfall amounts yesterday were generally below an inch across
the area. However, a few locations from Washington County Florida
into SW Georgia received closer to 2 inches. With river levels
running quite low, any rises seen no area rivers will be minor.the
next chance for rain will come on Sunday.


.Preliminary Point Temps/PoPs...

Tallahassee   49  20  57  23  67 /   0   0   0   0   0
Panama City   49  28  55  36  65 /   0   0   0   0   0
Dothan        45  22  54  30  64 /   0   0   0   0   0
Albany        46  21  55  26  64 /   0   0   0   0   0
Valdosta      48  21  55  25  64 /   0   0   0   0   0
Cross City    52  21  58  25  66 /   0   0   0   0   0
Apalachicola  50  27  55  34  65 /   0   0   0   0   0


.TAE Watches/Warnings/Advisories...

FL...Hard Freeze Warning from 11 PM EST /10 PM CST/ this evening to 9
     AM EST /8 AM CST/ Wednesday for Calhoun-Central Walton-
     Coastal Bay-Coastal Dixie-Coastal Franklin-Coastal Gulf-
     Coastal Jefferson-Coastal Taylor-Coastal Wakulla-Gadsden-
     Holmes-Inland Bay-Inland Dixie-Inland Franklin-Inland Gulf-
     Inland Jefferson-Inland Taylor-Inland Wakulla-Inland Walton-
     Jackson-Lafayette-Leon-Liberty-Madison-South Walton-

     Red Flag Warning until 5 PM EST /4 PM CST/ this afternoon for
     Central Walton-Coastal Bay-Coastal Wakulla-Inland Bay-
     Inland Wakulla-Leon-South Walton-Washington.

     Fire Weather Watch Wednesday afternoon for Coastal Bay-Coastal
     Wakulla-Inland Bay-Inland Wakulla-Leon-Washington.

GA...Hard Freeze Warning from 11 PM this evening to 9 AM EST
     Wednesday for Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay-

AL...Hard Freeze Warning from 10 PM this evening to 8 AM CST
     Wednesday for Coffee-Dale-Geneva-Henry-Houston.

     Red Flag Warning until 4 PM CST this afternoon for Coffee-Dale-

     Fire Weather Watch from Wednesday morning through Wednesday
     afternoon for Coffee-Dale-Geneva-Henry-Houston.

GM...Small Craft Advisory until 10 AM EST this morning for Apalachee
     Bay-Coastal waters From Ochlockonee River to Apalachicola
     FL out to 20 NM-Coastal waters from Suwannee River to
     Keaton Beach FL out 20 NM-Coastal waters from Apalachicola
     to Destin FL out 20 NM.

     Small Craft Advisory until 9 AM EST Wednesday for Waters from
     Suwannee River to Apalachicola FL from 20 to 60 NM-Waters
     from Apalachicola to Destin FL from 20 to 60 NM.



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