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).