AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1006 AM EST Thu Jan 31 2013

…Possible short duration light freeze tonight…
…Another freeze possible Friday night…

.NEAR TERM [Through Tonight]…
Updated at 945 am EST-
The 12 UTC regional surface analysis showed the cold front that
moved through our forecast area last night was over South FL,
while a 1024 mb high pressure ridge (centered over LA) was
building east along the Gulf Coast. Vapor imagery and upper air
data showed a broad trough over much of the eastern CONUS, with
plenty of dry air throughout the atmospheric column. Based on our
12 UTC KTAE sounding and the latest NWP guidance, we expect high
temperatures today will be in the mid to upper 50s.

With the ridge building in quickly, surface winds will likely
become calm shortly after sunset. This will allow for rapid
cooling, and a light freeze is possible at our normally coldest
sites (inland, relatively “open” areas away from cities). Even for
those areas that don`t quite reach freezing, frost will be
possible. The one limiting factor (which could prevent a deeper
freeze) will be the potential for surface winds to increase
slightly shortly before dawn, ahead of a dry cold front just to
the north.

&&

.SHORT TERM [Friday Through Saturday]…
High Temps both Friday and Saturday will be slightly below
climatology and generally range from the upper 50s NW to the mid
60s SE. On Friday night, however, we could see one of the coldest
nights of the entire Winter Season thus far, as the Sfc Ridge
behind the Dry Cold Front will be positioned right overhead of the
CWA. This will allow for nearly ideal conditions for Radiational
Cooling with clear skies and near calm winds. Low Temps could
bottom out in the middle 20s over much of the interior, which will
result in at least a long duration light freeze, and the
possibility of the first Hard Freeze of the season. Therefore, all
outdoor interests and those with sensitive vegetation should keep
abreast of the latest information from the National Weather
Service in Tallahassee.

&&

.Long Term [Sunday night through Thursday]…
Undated at 945 am EST-
Mostly zonal flow will dominate on the southern periphery of
broad eastern U.S. troughing through the period. A weak impulse
will pass overhead late on Monday, however, dry air will limit the
impacts to passing high clouds with no chance for rain. A slightly
stronger mid/upper wave will approach towards the end of the
period. At this time, little to no rain is expected with this
disturbance either. Overall, the period will be dominated by dry
conditions and near or slightly above average temperatures.

&&

.AVIATION [through 18 UTC Friday]…
Undated at 945 am EST-
Unlimited visibility and ceilings will prevail through the period.
Winds will be NW 5 to 10 KT this afternoon, light overnight, then
NW 5 to 10 KT again Friday. The only possible visibility
restriction could be caused by any large fire occurring near a
terminal, but currently we don`t see any “hot spots” on
satellite/radar imagery that would concern us.

&&

.MARINE…
Updated at 945 am EST-
Winds & seas were still solidly at advisory levels, but the latest
NWP guidance (including high resolution RAP and local 4km WRF) is
unanimous in having the winds fall below advisory criteria by
early afternoon. Thereafter, light to moderate offshore winds and
seas will dominate through Friday, with a period of cautionary
northeasterly winds expected on Friday night. Then, light winds
and low seas are anticipated for the upcoming weekend and
beginning of next week.

&&

.FIRE WEATHER…
Very dry conditions will overspread the region today and continue
into the weekend. Red flag conditions look like a near certainty
across much of North Florida today and possibly again on Friday.
Though RH values will be below 25 percent in Alabama and Georgia
today and on Friday, it appears as though the other required
criteria (winds and/or fuel moisture) will not be met. More moist
conditions will return by Sunday, putting an end to any red flag
concerns.

&&

.HYDROLOGY…
Despite a fairly widespread rainfall across the region on Wednesday
(with most areas receiving between 0.50″ and 2″ of rain, with the
highest amounts well to the N and W), only minor rises have been
observed on area rivers thus far. The only exception appears to be
the Choctawhatchee River, where the river may rise to near action
stage at Caryville during the next few days.