Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 120204
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
904 PM EST Wed Dec 11 2013
.NEAR TERM [Until 6 AM Thursday Morning]...
Low level moisture will increase from the southeast overnight
resulting in an increase in low level cloudiness, particularly along
and southeast of a line from Tallahassee to Tifton. This cloud cover
will also help keep overnight temperatures a little warmer tonight,
generally in the mid to upper 40s. Because of the increased cloud
cover, min temps were bumped up about a degree over the
southeastern zones. Overnight, a reinforcing shot of cooler and
drier air will begin to move into the region behind a dry cold
front. While the coldest air won`t arrive until late Thursday,
this dry front will result in increased winds, making Thursday
morning seem rather cool for areas in Southern Alabama and Georgia
where wind chills will drop into the upper 20s. Actual temps could
briefly touch freezing over Coffee and dale Counties in Southeast
AL. However, durations will be too brief for a warning.
.SHORT TERM [6 AM Thursday Morning Through Friday Night]...
Cold air advection will be underway Thurs morning as a dissipating,
dry cold front moves through the forecast area. Despite plenty of
sun highs will only reach the upper 50s to lower 60s (except mid 60s
around Cross City). This is close to average, but north winds of 10
to 15 MPH will make it feel a little cooler. 500 mb heights will
gradually rise beginning Thurs as the trough (currently off the Baja
coast) ejects eastward into the Southern Plains by Friday. Despite
these height rises, Friday morning will likely be the coldest this
week- thanks to a very dry airmass, clear skies, and light winds.
However, our forecast is generally a few degrees warmer than the MOS
consensus, since winds may not be completely calm all night, and MOS
has frequently been too cold so far this cool season. Still, a few
of our normally colder inland sites may briefly reach freezing, and
patchy frost may develop where temperatures dip into the mid 30s.
Highs on Friday will range from the lower 60s north to around 70
around Cross City.
.LONG TERM [Saturday through Wednesday]...
The GFS and ECMWF are in agreement on a wet weekend, but they differ
on the timing of the system generating the rain. The GFS forecasts a
fairly standard cold front passage Saturday night, while the ECMWF
has a very "wavy", complex frontal system that will not exit our
region until Sunday night. Our forecast is in between these
solutions. With plenty of deep layer moisture and Q-G forcing, and
adequate 0-6 km vertical wind shear, there is a non-zero chance of
an isolated severe storm. However, CAPE values are likely to be
under 500 J/KG with poor mid tropospheric lapse rates. Additionally,
neither global model forecasts an impressive 850 mb jet stream- a
prerequisite for tornado outbreaks in the Gulf Coast this time of
year. A seasonably cool, dry airmass will be in place across the
forecast area Mon through Wed, with near-average temperatures.
[Through 00Z Friday] MVFR cigs moving in from the east will affect
VLD tonight, with scattered low level cloud coverage possibly
reaching TLH and ABY as well. Tomorrow VFR cigs and vsbys will
prevail, but winds will be a little stronger than usual. North winds
around 10-15 kt will be seen across the area, with gusts in the
15-20 kt range likely at ECP, DHN, and ABY after sunrise.
Winds and seas have been subsiding rather quickly today, but they
are expected to increase overnight and early Thursday, perhaps
approaching advisory levels on Thursday. Conditions will improve some
temporarily on Friday, but Saturday will be rough for boaters as
rather strong winds and rough seas affect the region ahead of an
approaching cold front.
While dry conditions with relative humidity values less than 25
percent are expected on Thursday, the other criteria needed for red
flag conditions will not be met in the tri-state area. Increasing
low level moisture on Friday will result in higher afternoon RH
values. A storm system will move through the region this weekend
bringing at least an inch of rain to the region. Dry conditions
will return by Monday.
The next chance of rain is expected over the weekend, with rainfall
totals of 1-3 inches. Currently most area river stages are at or
slightly above base flow. Rainfall totals in this range would
result in rises.
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 45 62 34 66 52 / 10 0 0 0 20
Panama City 47 61 42 65 57 / 10 0 0 0 40
Dothan 35 57 34 61 50 / 0 0 0 0 40
Albany 36 58 33 62 49 / 10 0 0 0 30
Valdosta 45 61 36 66 53 / 10 10 0 0 20
Cross City 54 67 36 71 53 / 10 10 0 0 10
Apalachicola 51 63 42 65 59 / 10 0 0 0 30
SHORT TERM/LONG TERM...Fournier