Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 121513
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1013 AM EST Thu Dec 12 2013
.NEAR TERM [Today]...
Chilly airmass will continue to work into the region today as high
pressure builds into the Tennessee Valley. Current 10am temperatures
(upper 40s and lower 50s) are a few degrees ahead of the current
forecast. In addition, 12Z KTLH sounding supports max temps a few
degrees higher as well. Therefore, only change to forecast for
this morning will be to bump up max temps a couple of degrees.
.SHORT TERM [Tonight Through Saturday Night]...
The short term will start off dry with cool high pressure the
dominant feature. Overnight lows tonight may dip to near freezing
in a few of the normally colder locations, but a widespread freeze
is still not expected. This is mainly due to the expectation
that winds may not go completely calm with high pressure centered
north of the area, and MOS has had a tendency to be a few degrees
too cold so far this cool season. The official forecast went on
the warmer side of the guidance spread for tonight.
Friday will be a transition day as surface ridging moves to the
east and the flow turns more southeasterly. The next system will
still be too far away to give us any chance of precip on Friday
though. Highs will be near the seasonal average.
Guidance is in agreement that Saturday will be a wet day as the
next system affects the area. Moisture return looks fairly
substantial with this system, and the eastern Gulf of Mexico SSTs
are currently above average for this time of year due to the lack
of very many cold air intrusions so far this cool season. There
remains a non-zero chance of isolated severe storms on Saturday
and/or Saturday night with this system, but it currently looks
like a lower end threat as the dynamics are not overwhelming and
the instability still looks a bit marginal despite the strong
moisture return. One additional thing to watch out for may be the
threat of heavy rain due to training convection. Both the GFS and
NAM forecast precipitable water values to rise to over 1.75 inches
on Saturday evening, which is near the 99th percentile for
December. (The December record is 2.00 inches.) As this occurs,
guidance shows the front temporarily slowing down, and training
convection would become a possibility with several inches of rain
occurring in a short amount of time over localized areas.
.LONG TERM [Sunday through Wednesday]...
A decreasing trend in the rain is expected during the day Sunday
as the front clears the area. Then, a seasonably cool, dry
airmass will be in place across the forecast area Monday through
Wednesday, with near-average temperatures.
.AVIATION [Through 12Z Friday]...
The threat for any period of MVFR Cigs has now passed, so nearly
unlimited VFR conditions should rule the skies for the next 24
hours. The only expected aviation hazard will be gusty winds out
of the N and NW during the daylight hours.
Winds and seas are increasing as advertised this morning, with
offshore locations showing winds exceeding 20 knots with seas at
5-6 feet. Elevated winds should continue through the evening
before diminishing overnight as high pressure edges closer to the
area and the gradient weakens. No changes planned to the forecast
with the morning update.
Relative humidity values will be quite a bit lower across the
region this afternoon, but it still appears that the other
necessary criteria for Red Flag conditions for each of our 3
states will not be met. However, as we gradually get into a drier
pattern, conditions will have to be monitored more closely as time
goes on, especially if ERCs begin to increase in FL and Fuel
Moisture levels start to drop in GA.
Average rainfall totals of 1 to 3 inches are expected this weekend,
but localized amounts around 5 inches are possible if training
convection occurs on Saturday. These rainfall totals will result in
rises along area rivers.
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 59 33 66 51 73 / 0 0 0 10 70
Panama City 59 40 64 56 73 / 0 0 0 20 70
Dothan 54 32 61 49 71 / 0 0 0 20 70
Albany 55 32 62 48 70 / 0 0 0 10 80
Valdosta 58 34 65 49 73 / 0 0 0 10 70
Cross City 63 35 70 51 75 / 0 0 0 10 50
Apalachicola 61 41 64 57 72 / 0 0 0 20 70
GM...SMALL CRAFT ADVISORY until 4 AM EST Friday for Waters from
Suwannee River to Apalachicola FL from 20 to 60 NM-Waters
from Apalachicola to Destin FL from 20 to 60 NM.