Area Forecast Discussion
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FXUS62 KTAE 211141
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
641 AM EST Tue Feb 21 2017

.NEAR TERM [Through Today]...

A narrow, mesoscale rain band developed near Mobile a few hours
ago, well ahead of forecast. Although this rain band appeared to
be moving into a progressively cooler and drier PBL, it has
recently intensified (though there was no lightning). Judging by
the wind observations, there appears to be enough of a surface-
based cold pool to keep this feature translating eastward into our
forecast area this morning before dissipating in a region of less
favorable thermodynamics. This feature has not been initialized
by any of the mesoscale guidance, so we went with "old school"
forecasting, and we believe it will make it to the
Chattahoochee/Apalachicola Rivers before dissipating later this
morning. We updated the early morning forecast to account for this
change in thinking; otherwise the forecast appears to be on
track, and more rain will develop across the region later this
afternoon.

The warm air aloft and increasing deep-layer moisture will actually
work against organized/severe convection as mid-layer lapse rates
will be poor, resulting in weak updrafts. Additionally, forecast
surface dewpoints will only reach the lower to mid 60s. Still, a
few thunderstorms are expected across the Panhandle and adjacent
coastal waters where MLCAPE is maximized. The increasing clouds
will help tamp down high temperatures a bit, with highs in the mid
to upper 70s. This is still well above climatology.

&&

.AVIATION [Through 12Z Wednesday]...

LIFR cigs have just recently developed at KVLD, but we expect
this to dissipate by mid morning. SHRA will affect KDHN and KECP
by mid morning, followed by a lull there early in the afternoon,
then more rain late afternoon, continuing well into tonight. This
rain will spread east and affect KTLH and KABY overnight. We
expect widespread MVFR cigs and Vis overnight.

&&

.PREV DISCUSSION [323 AM EST]...

.SHORT TERM [Tonight Through Thursday]...

The trough will move out into the northeastern Gulf Wednesday and to
south FL on Thursday. As the system moves southeastward, the highest
rain chances will shift from southeast AL and the FL Panhandle
tonight down to the FL Big Bend and our coastline. With deep layer
flow from the south through Wednesday, Gulf moisture will be
plentiful and we expect to get a good soaking rain over the next 2
days- about 2-3" west of a line from Apalachicola, FL to Enterprise,
AL. As we`ve received relatively little rainfall, and are about 1.5"
below normal for the month to date, this rain is not expected to
cause widespread flooding concerns, although localized flooding
cannot be completely ruled out. Warm air aloft will keep
instability low, so any lightning with these storms should be
isolated and mostly out over the water.

Temperatures Wednesday will be moderated by heavy cloud cover, with
afternoon highs in the low to mid 70s and morning lows only in the
low 60s both Wednesday and Thursday morning. Once the system clears
by Thursday afternoon, however, highs are expected to return to the
upper 70s to around 80.


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

Caught between a broad trough over the central CONUS and a decaying
shortwave trough off the east coast of S FL, a weak pattern will be
in place over the southeast through Friday. As the broad trough
swings into the Ohio Valley Saturday, however, it will sweep through
our next cold front. Chances for rain will be lower with this
system, peaking at 20%, but is expected to bring a brief relief in
the warm temperatures. Highs in the upper 70s to low 80s and lows in
the upper 50s will continue ahead of the front, dropping to highs in
the upper 60s to low 70s and lows in the 40s Saturday and Sunday. By
Monday, deep layer ridging and above normal temperatures will
return.


.MARINE...

Cautionary conditions are expected today over our western waters and
Wednesday over our eastern waters as a weak low pressure system
approaches, then sinks south of our coastal marine zones. A weak
pressure pattern will move into place in its wake until the weekend.
Saturday, winds will increase again as a dry cold front makes its
way through our area.


.FIRE WEATHER...

With high rain chances through Wednesday, there are no fire weather
concerns.


.HYDROLOGY...

Two to three inches of rain are expected over the next two days west
of a line from Apalachicola, FL to Enterprise, AL. This may cause
some slight rises along our area rivers, but is not expected to
cause flooding.

&&

.PRELIMINARY POINT TEMPS/POPS...

Tallahassee   77  61  75  60  80 /  40  70  50  30  10
Panama City   71  61  71  60  74 /  80 100  60  20  10
Dothan        75  60  74  58  78 /  90 100  30  10   0
Albany        77  61  76  59  79 /  50  70  40  20  10
Valdosta      78  62  76  61  80 /  10  50  60  40  10
Cross City    80  62  75  61  78 /  10  50  70  40  30
Apalachicola  72  62  71  61  75 /  50  90  70  30  10

&&

.TAE WATCHES/WARNINGS/ADVISORIES...

FL...High Rip Current Risk through late tonight for Coastal Bay-South
     Walton.

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

&&

$$

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


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