Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 042040
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
340 PM EST Wed Dec 4 2013
...Unseasonably warm days and overnight fog through Friday...
.NEAR TERM [Through Tonight]...
The upper ridge across the Southeast continues to gradually amplify
as a short wave trough digs into the base of a western U.S. trough.
Plenty of upper level clouds continue to stream into the region.
Surface analysis continues to show high pressure centered northeast
of the area off the Mid Atlantic coast. A cold front is advancing
east toward the Lower Mississippi Valley. In between these two
systems, we continue to see deep layer southern flow into the
forecast area. This allowed temps to reach 80 in a few spots this
afternoon. Sea fog failed to develop today across the Apalachee Bay
as previously anticipated. Scattered showers are also a bit more
numerous and we expect these to continue to impact our western zones
for a while overnight. These factors, when combined with the
aforementioned cirrus have stayed our hand in terms of putting out a
long lead time dense fog advisory. We still believe that dense fog
is likely to develop across the region eventually and most of our
statistical and hi res guidance supports this. An advection-type fog
is still possible with nearshore SSTs now in the upper 50s to lower
60s and upper 60s dew points advecting over that. Do not be
surprised to see a dense fog advisory eventually for parts of the
forecast area. Overnight lows will once again be 15-20 degrees above
.SHORT TERM [Thursday Through Friday Night]...
An upper level ridge will continue to build from the Gulf across the
western Atlantic as a western trough swings into the midwest.
Elsewhere in the CONUS an arctic airmass will push south into the
southern plains strectching to the Ohio River valley, resulting in
a band of significant icing and snow. A 5910m ridge across central
and south Florida will allow daytime highs to climb 15 degrees
above normal for the next couple of days. Highs will be near 80
Thursday and Friday, with mild overnight lows in the lower to mid
60s (which are close to the normal high temperatures for early
Dewpoints have increased from the lower to mid 50s to the lower to
mid 60s in the past 24 hours and will remain in the 60s through the
period. This warm and moist flow over the relatively cooler shelf
waters of Apalachee Bay will likely result in sea fog which will
move inland Thursday night. Friday night the flow decreases in
advance of a cold front which will weaken advection, but we still
expect areas of fog. Fog will be slow to burn off, likely
persisting into late morning tomorrow and Friday, due to the very
moist boundary layer and low sun angle.
The warm and moist onshore flow will result in isolated showers,
mainly north and west of Tallahassee tomorrow and Friday. Also
we cannot rule out an isolated afternoon thunderstorm with the
weak surface instability. As we close in on the weekend, the
midwest cold front will approach the SE, moving to the Florida
panhandle, SE Alabama and central Georgia by late Friday night.
.LONG TERM [Saturday through Wednesday]...
This period will feature a couple of frontal systems. The first
cold front moves into the SE late Friday night, but becomes
stationary from the central FL panhandle to southeast GA by
Saturday evening. This front then pushes back north as a warm
front Saturday night, meaning that our area never gets into the
deeper moisture or lift behind the front. The drier return flow on
Sunday is short-lived, as a second much stronger cold front pushes
through the area late Monday night into early Tuesday. This front
has the upper support to push all the way south across the FL
peninsula, putting AL, GA, and northern FL well into the cold air.
As a result, the very warm temperatures of the past week could
drop by 15 to 20 degrees behind the front on Tuesday and
Wednesday, with readings in the 50s in SE Alabama and SW Georgia
to the 50s and lower 60s across northern FL.
Precipitation will generally be scattered through the period with a
chance of thunderstorms along and ahead of the first front Saturday
and again with the much more vigorous front on Monday.
.AVIATION...[Through 18 UTC Thursday] Fog is expected to develop
across much of the area and we are forecasting VLIFR/LIFR
visibility to develop at TLH, ECP and VLD between 02-04 UTC.
Further inland, we held visibility at IFR, but show low cigs.
These areas could see the visibility drop lower than forecast if
showers dissipate. There will a slow improvement Thursday morning
and VFR conditions are not expected until between 15-16 UTC. &&
Moderate onshore flow is forecast to continue over the coastal
waters into the weekend, with wind speeds occasionally approaching
exercise caution levels. Sea fog is expected to be an issue
beginning tONIGHT, especially over Apalachee Bay. Conditions will
continue to favor sea fog development through at least Friday. &&
Red flag conditions are not expected the next several days. Areas of
dense fog are expected to develop over the next several nights with
poor mixing and light winds. A cold front will bring much drier air
to the region for Tuesday and Wednesday. However, the RH is
currently forecast to remain above critical levels.
While there is a chance of rain through the weekend, total QPF
amounts will not be enough to have an impact on river stages.
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 62 80 60 79 62 / 10 10 10 10 10
Panama City 66 77 66 77 65 / 20 20 10 10 20
Dothan 63 80 63 80 59 / 30 30 10 10 30
Albany 61 81 61 81 63 / 20 20 10 10 20
Valdosta 60 81 61 80 61 / 10 10 10 10 10
Cross City 60 81 59 81 58 / 10 10 10 10 10
Apalachicola 66 75 64 75 65 / 10 10 10 10 10