Area Forecast Discussion
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443
FXUS62 KTAE 260712
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
312 AM EDT Wed Jul 26 2017

.NEAR TERM [Through Today]...

This evening`s surface and upper-air analyses showed a weak area of
low pressure across south GA (850-500 mb), with ample deep layer
moisture concentrated along the low`s southern flank. The 1000-700
mean winds across much of our forecast area will be from the north
today, on the western periphery of this low. This will likely pin
the FL Big Bend and Panhandle sea breeze fronts at the coast until
mid to late afternoon, which means a later start to our daily
thunderstorms. The highest PoPs (60%) will be around Tallahassee,
Madison, Valdosta, and Tifton, where there will be more favorable
moisture and mesoscale forcing. (The FL/GA east coast sea breeze
fronts may also play a role in GA`s late afternoon storms).
Elsewhere PoPs will be 30 to 40%.

Despite the presence of the low pressure system, deep-layer vertical
wind shear will be light (15 kt or less) and mid-layer lapse rates
unimpressive (6 C/km), and not conducive for organized severe
storms. However, there is almost always enough CAPE and mesoscale
forcing during the summer afternoons to support a few "pulse severe"
storms, capable of producing marginally damaging winds and/or hail.
High temperatures will be in the lower 90s.


.SHORT TERM [Tonight Through Friday]...

With the absence of any appreciable upper level flow across the
region, the mid-level low currently meandering in the region will
persist through much of the short term period before an amplifying
trough across the eastern third of the CONUS kicks it eastward
Friday. This feature will continue to influence shower and
thunderstorm development each day, with POPs generally ranging in
the 30 to 50% range. Low to mid level northerly flow due to the
position of the aforementioned low will likely delay the progress
of the daily sea-breeze circulation, resulting in a later start of
convection each day. Some model guidance is hinting at some mid-
level dry air impinging upon the region on Friday, which would
lower storm coverage somewhat and result in warmer temperatures.
Expect afternoon highs in the low to mid 90s each day, with
overnight lows in the low to mid 70s.


.LONG TERM [Friday Night Through Wednesday]...

The amplifying trough and associated upper low mentioned in the
short term discussion will swing eastward across the eastern third
of the CONUS Friday night into Saturday. An associated front will
sag southward through the region Saturday, bringing with it
increased shower and storm chances. While the front will likely
dissipate across the region, the latest model guidance is in
better agreement tonight in northwesterly flow bringing drier air
into the northwestern half of region for the latter part of the
weekend, yielding a brief reprieve of shower and thunderstorm
activity in these areas. Abundant moisture continues to be progged
to stick around across the southeastern half, with associated
shower and storm chances remaining elevated in these locales.
Moisture will gradually spread inland once again through the work
week, as high pressure builds to the east of the area with shower
and thunderstorm chances each day. Increased cloud cover and storm
coverage will keep afternoon highs limited to the upper 80s to
low 90s through much of the period, with lows in the mid 70s.

&&

.AVIATION [Through 06Z Thursday]...

The numerical guidance consensus forecasts areas of IFR (or lower)
cigs and/or MVFR-IFR Vis across south GA and AL overnight. While
recent obs in south GA show this forecast verifying so far, low
cigs/fog were also developing at KTLH and a few other NW FL sites.
Thus we`re now forecasting periods of IFR conditions at all
terminals but KECP overnight. Conditions will return to VFR by mid
morning. Scattered to numerous TSRA will develop across the region
mid to late afternoon, especially at KTLH and KVLD where deep layer
moisture will be maximized. Elsewhere PoPs will be 40% or less, not
quite high enough to include in this TAF package.

&&

.MARINE...

Southwesterly winds generally around or below 10 knots and seas up
to 2 feet will prevail through the next several days. Winds of 10 to
15 knots and seas up to 3 feet will be common this weekend as a
weakening front approaches coastal waters. Showers and thunderstorms
are possible each day.

&&

.FIRE WEATHER...

No concerns.

&&

.HYDROLOGY...

All rivers are expected to remain below flood stage over the next
several days. Afternoon showers and thunderstorms could yield
locally heavy rainfall in some locales across the region.

&&

.PRELIMINARY POINT TEMPS/POPS...

Tallahassee   91  74  91  74  95 /  60  30  40  20  30
Panama City   89  77  90  78  91 /  40  20  30  20  20
Dothan        91  73  93  74  94 /  30  20  30  10  30
Albany        90  74  90  74  93 /  40  20  40  10  30
Valdosta      88  74  91  74  93 /  70  40  50  20  40
Cross City    90  74  90  75  91 /  20  20  40  20  30
Apalachicola  89  77  90  77  92 /  40  20  40  20  20

&&

.TAE WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

NEAR TERM...Fournier
SHORT TERM...Pullin
LONG TERM...Pullin
AVIATION...Fournier
MARINE...Pullin
FIRE WEATHER...Fournier
HYDROLOGY...Pullin



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