Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 101919
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
219 PM EST Tue Dec 10 2013
.NEAR TERM [Through Tonight]...
The cold front continues to make progression through the far eastern
portions of the forecast area and move into the Florida Peninsula.
Surface data continue to show the drier and cooler air overspreading
the forecast area. Surface high pressure at 19 UTC was located
across Northwestern Arkansas. This evening and overnight this area
of high pressure will spread quickly eastward into the Tennessee
River Valley and be near West Central Virginia by sunrise. With the
high pressure center remaining well to the north of the area, the
resulting pressure gradient will be sufficient enough to support 5
to 10 kt sustained winds across most of the area during the night.
Moreover, the flow will be veering throughout the night, which is
not the best scenario either for very low temperatures. As a result,
think any radiative effects will be diminished and temperatures will
gradually fall overnight into the low to mid 40s across north
Florida tapering down into the mid to upper 30s in Southern
Alabama/Georgia. If there is a weak spot in the pressure gradient,
it is across East Central Alabama and West Central Georgia, so our
northern tier of counties will have the best chance of dropping to
the 33 to 35 degree range. This is supported by the vast majority of
the model guidance, which continues to indicate much warmer
temperatures than the GFS-based MAV guidance, which has had quite a
cold bias this weekend with post-frontal airmasses.
.SHORT TERM [Wednesday Through Thursday Night]...
Much of the eastern CONUS will be dominated by a broad long wave
trough at 500 mb, and a large area of high pressure at the surface.
The airmass across our region will be cool and dry, with near
average temperatures (i.e. lows in the upper 30s to mid 40s and
highs in the 60s). However, low temperatures may approach freezing
in our normally colder inland sites Friday morning, provided that
the wind stays calm.
.LONG TERM [Friday through next Tuesday]...
The zonal 500 mb flow and fair & mild weather on Friday will give
way to high rain chances this weekend, as a cold front moves through
the region. The PoP will increase from west to east Fri night/Sat
morning, then taper off from west to east on Sun. The GFS was a bit
faster than the ECMWF, but they both indicate very high PoPs. There
appears to be enough vertical wind shear and forcing for a non-zero
chance of a few severe storms, but as usual, the instability looks
marginal with SBCAPE values around 500 J/KG or less and poor mid
tropospheric lapse rates. There is also the question of whether or
not these storms will be surface based. Fair weather and
near-average temperatures are expected behind the cold front through
.AVIATION [Through 18z Wednesday]...
Post-frontal MVFR ceilings will continue to thin and move out of the
area before sunset. Expect VFR conditions to prevail at all sites by
23z this evening and remain in place through the end of the TAF
cycle on Wednesday. Gusty winds this afternoon should diminish by
The tight pressure gradient overnight will keep winds and seas at
advisory levels. This gradient will temporarily weaken on Wed, as
winds drop to around 10 KT late Wed afternoon. However, a strong
high pressure system will develop across the Tennessee Valley Wed
night and Thurs, causing winds and seas to once again approach
No fire weather concerns are expected on Wednesday, however a
reinforcing shot of drier air on Thursday will create the potential
for fire weather conditions across North Florida, depending on the
ERC values. Elsewhere on Thursday, while relative humidity values
will be near critical levels, durations of low relative humidity
will not be met. A moistening trend begins on Friday which will end
any potential red flag concerns until next week.
Today`s frontal passage brought rain amounts up to 0.5 inch. The next
chance of rain is expected over the weekend, with rainfall totals of
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 41 65 43 62 33 / 0 10 10 0 0
Panama City 43 63 47 62 40 / 0 0 0 0 0
Dothan 35 60 36 58 32 / 0 0 0 0 0
Albany 35 61 36 60 31 / 0 0 0 0 0
Valdosta 42 63 43 61 34 / 0 10 10 0 0
Cross City 47 69 49 67 34 / 10 10 10 10 0
Apalachicola 49 65 49 63 39 / 0 0 0 0 0
GM...SMALL CRAFT ADVISORY until 5 AM EST Wednesday for Apalachee
Bay or Coastal Waters From Keaton Beach to Ochlockonee
River Fl out to 20 Nm-Coastal Waters From Ochlockonee
River to Apalachicola Fl out to 20 Nm-Coastal waters from
Suwannee River to Keaton Beach out 20 NM-Coastal waters
from Apalachicola to Destin FL out 20 NM-Waters from
Suwannee River to Apalachicola FL from 20 to 60 NM-Waters
from Apalachicola to Destin FL from 20 to 60 NM.