Area Forecast Discussion
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FXUS62 KTAE 171148
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
648 AM EST Tue Jan 17 2017

.AVIATION [Through 12Z Wednesday]...

Currently MVFR VSBY at VLD with possible IFR conditions before or
around daybreak. Otherwise, brief periods of MVFR conditions
possible at the remaining sites. Then, VFR conditions at all
sites aft 15Z with light southerly winds. A better chance for
widespread fog developing after 03z.

&&

.PREV DISCUSSION [301 AM EST]...

.NEAR TERM [Through Today]...

Deep layer ridging will remain over the local area. The east to west
surface ridge axis will drop slowly southward through the day as a
cold front presses further into the southeast CONUS from the
northwest. Low level southeast to south flow will continue to pull
in gulf moisture with PWAT values rising to 1.0-1.5" mainly west of
the river. As a result of the increasing moisture, very warm
temperatures and some modest isentropic lift, there will be a slight
chance for showers (20%) mainly along and west of a line from
Dothan to Panama City. Temperatures will be around 80 degrees.


.SHORT TERM [Tonight Through Thursday]...

Weak upper ridging is in place through much of the short term with
southwest to west flow across the CWA. At the surface, high pressure
is situated over the Atlantic and with the CWA on the western side,
flow is southerly at the surface, which will continue the flow of
Gulf moisture into the area. Although still on the lower side, rain
chances will increase Wednesday (widespread 20%) with increasing
moisture and isentropic lift. These chances will increase to
30-60% with the higher values across the western portion of the
CWA Thursday afternoon as a cold front approaches the southeast.
There`s enough instability (~400 J/kg) to mention isolated
thunderstorms on Thursday, however shear values aren`t impressive
at this time.

With southerly flow, temperatures will remain well above normal with
highs in the mid 70s and lows in the mid 50s to lower 60s.


.LONG TERM [Thursday Night Through Tuesday]...

The main focus of the forecast is on the long term with multiple
disturbances affecting the CWA. It will be a wet start to the long
term with a low pressure system moving across the Midwest Thursday
night and pushing a front into the CWA. While there should be a
break in precipitation by Friday night, this will not last long. A
weak surface low develops along the Gulf coast Saturday and tracks
northward into the lower Mississippi Valley, lifting a warm front
northward across the CWA on Saturday. This will bring the return of
the higher precipitation chances in addition to 1000 J/kg of CAPE
across the CWA. This, combined with 50kts of deep layer shear, will
allow for some strong to severe storms on Saturday however the
stronger parameters hold off until Saturday night into Sunday as
a surface low (associated with a strong upper level closed low)
sweeps across TX and absorbs the low that initially helps to push
the warm front northward across the CWA. As this stronger system
approaches, the GFS indicates more than 1500 J/kg of CAPE late
Saturday night into Sunday morning with around 60kts of deep layer
shear and 20-25kts of low layer shear. Given these values there is
the potential for severe storms. With multiple disturbances moving
through the southeast though and this still being 4-5 days out, do
not focus on the exact timing as this may still change, but
instead focus on the general chance for severe weather this
weekend and stay closely tuned into the forecast.

Although the front should clear the area Sunday night, with the
strong upper low lifting across the south and TN valley on Monday
some lingering showers may persist into early next week. While the
front will bring heavy rain and the potential for severe weather to
the CWA over the weekend, it will also bring more seasonable high
temperatures to the area on Monday with highs decreasing about 10
degrees behind the front.


.MARINE...

Winds will be southeasterly around 10 knots for the next few days
with winds and seas increasing late Thursday with a front
approaching. Rain chances will increase for the second half of the
week through the weekend with multiple disturbances affecting the
marine area. With a strong front moving through the marine area
Sunday into Monday, wind speeds increase to Small Craft Advisory
with Gale force gusts. This will also drastically increase seas to
more than 10 feet.


.FIRE WEATHER...

Hazardous fire weather conditions are not expected over the next
several days.


.HYDROLOGY...

Rain chances will increase late in the week through the weekend.
Heavy rainfall is possible with these disturbances. Latest
guidance shows widespread 2-4 inches across the area Thursday
through Sunday so the flooding potential will need to be monitored
closely.

&&

.PRELIMINARY POINT TEMPS/POPS...

Tallahassee   79  57  77  58  76 /  10  10  20  10  30
Panama City   75  63  72  62  72 /  10  10  20  20  40
Dothan        78  59  77  59  76 /  20  10  20  10  50
Albany        79  59  77  58  76 /  10  10  20  10  40
Valdosta      80  55  77  56  76 /   0   0  10  10  20
Cross City    79  53  77  55  77 /   0   0  10  10  10
Apalachicola  73  60  72  61  71 /  10  10  20  20  30

&&

.TAE WATCHES/WARNINGS/ADVISORIES...

FL...None.
GA...None.
AL...None.
GM...None.

&&

$$

NEAR TERM...Barry
SHORT TERM...Fieux
LONG TERM...Fieux
AVIATION...Barry
MARINE...Fieux
FIRE WEATHER...Barry
HYDROLOGY...Fieux


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