Area Forecast Discussion
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129
FXUS62 KTAE 281008
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
608 AM EDT Tue Oct 28 2014

.Near Term [Through Today]...
Dense fog across the region should dissipate around 9am once again
this morning.

The upper level pattern will be transitioning through the day from
deep layer ridging over the Southeast to broad troughing which will
cover much of the country by tomorrow. At the surface, flow will
veer to the south to the west of Apalachicola as high pressure
begins to retreat eastward. This southerly flow will create some
weak low-level isentropic ascent over the Gulf across a subtle
temperature gradient between the central and northeast Gulf. While
this normally wouldn`t be enough to generate any showers, there will
be some enhancement to the low-level ascent by an elongated
upper-level PV anomaly draped southwest to northeast through the
Gulf. The effects locally will likely just be some enhanced cloud
cover spreading inland across the Panhandle and southeast Alabama,
though a stray, light shower or two cannot be ruled out along and
west of a line from Panama City to Dothan. Just to be clear, most of
the expected shower activity will remain offshore and confidence in
any rain over land is extremely low.

.Short Term [Tonight Through Thursday]...
A cold front will begin to approach the region on Wednesday as a
storm system moves through the Ohio Valley. The models have been
consistent over the last several runs in keeping the southern end
of this system quite weak with limited chances of showers and
thunderstorms. See little reason with the overnight guidance to
deviate from the previous forecast, so will keep low end pops in
the forecast for Wednesday afternoon and into Wednesday night.
Drier air moves into the region for Thursday along with some
cooler air. Temperatures on Wednesday will continue to be in the
mid 80s, with a notable change arriving on Thursday when
temperatures return to normal levels.

.Long Term [Thursday Night Through Tuesday]...
Big changes are in store during the long term period. While there
are still notable differences between the Euro and GFS with the
eventual incoming airmass for the weekend, some key points are
starting to emerge. Essentially, the eastern CONUS trough will
amplify by Friday as a large mid level ridge builds over the
Rockies. The degree of this amplification and eventual path of a
surface anticyclone will largely dictate how much cold air makes
it to the Gulf Coast. Of the two models, the Euro is the most
aggressive showing a significant amplification of the pattern by
Saturday with a closed low moving off the Mid Atlantic States by
the first of the week. This opens the door for the first real cold
air intrusion to the Gulf. And with the surface ridge axis in the
model aligned over the region by Sunday morning, the Euro hints at
the potential for a frosty morning with lows in the mid to upper
30s.

The GFS favors less amplification and is also more progressive
with the pattern through the weekend, so this solution favors
milder temperatures as much of the cold air is vectored into the
Mid Atlantic and the surface high pressure stays well to the
north.

The GFS has offered stability in its solutions over the past few
days, while the Euro has struggled to maintain consistency.
Moreover, the 28/00z operational Euro seems to be quite removed
from the mean of the ensembles, so for now, have weighted our long
term forecast much closer to the GFS solution, which indicates a
cool snap, but certainly not as cold as suggested in the Euro.

By Monday, as the surface high pressure area moves off the
Atlantic Coast, easterly flow returns, signalling a gradual warm
up and a steady increase in low level moisture.

&&

.Aviation...
[Through 06Z Wednesday]
LIFR to IFR visibilities in fog will plague most of our terminals
this morning. Between 13-14z all restrictions due to fog will
dissipate returning sites to VFR. However, there is the possibility
of MVFR ceilings spreading south to north from ECP to DHN later this
afternoon.

&&

.Marine...
Light onshore flow will prevail through Wednesday ahead of an
approaching cold front. This front will move through the marine
area Wednesday night, shifting winds to offshore. A gradual
increase in offshore flow is expected with at least cautionary
conditions by late Friday or Saturday.

&&

.Fire Weather...
Hazardous fire weather conditions are not expected over the next
couple of days. A drier airmass is expected to arrive late this week
which may bring critical relative humidities to the region. Stay
tuned.

&&

.Hydrology...
With no significant rainfall through the next few days, rivers will
remain at low levels.

&&

.Preliminary Point Temps/PoPs...

Tallahassee   86  58  85  62  79 /   0  10  10  20  10
Panama City   81  67  81  62  76 /  20  10  10  20  10
Dothan        84  62  82  55  75 /  10  10  30  20  10
Albany        86  60  83  55  77 /   0   0  20  20  10
Valdosta      85  56  83  58  79 /   0   0  10  20  10
Cross City    85  57  83  60  82 /   0  10  10  20  10
Apalachicola  80  66  79  64  77 /  10  10  10  20  10

&&

.TAE Watches/Warnings/Advisories...

FL...Dense Fog Advisory until 10 AM EDT /9 AM CDT/ this morning for
     Calhoun-Central Walton-Coastal Bay-Coastal Franklin-Coastal
     Gulf-Coastal Jefferson-Coastal Taylor-Coastal Wakulla-
     Gadsden-Holmes-Inland Bay-Inland Franklin-Inland Gulf-
     Inland Jefferson-Inland Taylor-Inland Wakulla-Inland Walton-
     Jackson-Lafayette-Leon-Liberty-Madison-South Walton-
     Washington.

GA...Dense Fog Advisory until 10 AM EDT this morning for Brooks-
     Decatur-Grady-Lanier-Lowndes-Seminole-Thomas.

AL...Dense Fog Advisory until 9 AM CDT this morning for Coffee-Dale-
     Geneva-Henry-Houston.

GM...None.

&&

$$

NEAR TERM...HARRIGAN
SHORT TERM...GODSEY
LONG TERM...GODSEY
AVIATION...HARRIGAN
MARINE...GODSEY
FIRE WEATHER...HARRIGAN
HYDROLOGY...GODSEY






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