AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TALLAHASSEE FL 1021 PM EDT Fri Oct 21 2011

The National Weather Service in Tallahassee will be testing the
issuance of Area Forecast Discussions (AFD) in mixed case text. If
you wish to provide feedback regarding this test, please call
our office at (850) 942-8833. More information can be found at:

http://www.NWS.noaa.gov/om/notification/pns11mixedcasel.htm

.EVENING UPDATE...Clear skies and CALM winds are commonplace
across the entire area-of-responsibility right now. Therefore, the
focus for the evening forecast update was almost entirely on
TEMPERATURE trends. Through 02z, temperatures have been plummeting
at a more dramatic rate than the available guidance has been
willing to indicate. In fact, the 02z temperatures are cooler in
some areas than the NAM and GFS had forecast at 06z. Basically the
temperatures this evening have been tracking along, or just below
the lower limit of the guidance envelope, but have been very
similar to temperatures at this time last NIGHT. Based on the
22.00z SOUNDING observations of the 850mb temperatures, it looks
like the axis of cooler LOW-level AIR has shifted east and
therefore more of the CWA should be in the 30s for lows tonight.

For temperature trends, CURRENT conditions and trends from last
night were weighed and used to tweak a blend of MAV and MET MOS
down by a FEW degrees. The 18z MAV guidance came in particularly
cool for inland areas of Calhoun, Liberty, Gulf, and Franklin
Counties near the Apalachicola National Forest, with lows 34-36
degrees. This area was generally excluded from the initial FROST
ADVISORY, but it currently one of the coldest locations in our
area (temperatures already 44-48 degrees). AS such, lows were
nudged down slightly in that area, and the Frost Advisory was
expanded into those locations. That area, along with our far
western areas that were quite cold last night, are expected to be
the spots that are most at-risk for frost tonight. The remainder
of the forecast area should see lows 36-39 degrees, which is
rather borderline for any WIDESPREAD frost. We did not trim the
existing area of the Frost Advisory in Georgia in order to
maintain consistency, but the advisory was also not expanded any
further east. It`s not out of the question that a few typical cold
spots in the eastern part of our area may see some frost, but as
of now it`s not expected to be widespread enough to warrant an
advisory. Lows in the city of Tallahassee should be about 5-6
degrees warmer than at the airport. Our CLIMATE sites TLH and AAF
may approach record lows tonight (34 at TLH, 44 at AAF).