AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 230 PM EST Mon Dec 5 2011 .SHORT TERM (Tuesday through Wednesday night)... A long wave trough with a strongly positive TILT will extend from northern Quebec SWWD to the American Desert SW at the start of the period. A DOWNSTREAM RIDGE will remain parked over the FL peninsula. Surface high pressure will be centered SE of New England and continue to ridge swwd to FL. A slow moving cold FRONT will extend the LENGTH of the Appalachians and then swwd across AL to the N. Central Gulf of Mexico. We continue to see differences among the various models on the speed with which energy in the southern portion of the long wave trough will progress eastward across the southern U.S. This also maintains differences in the timing of the cold frontal passage. The 00Z Euro is on the fast side of the models with the 12Z NAM on the slower side. The GFS will be used as a compromise. Regardless of which model verifies best, the progress of the front should be pretty slow. We also anticipate some post-frontal precip with this system. Deep layer WSW winds aloft over the warm sector will warm the mid levels and limit instability. Therefore, little to no thunder is expected and none is included in the forecast. Looking at specific TEMP/POP trends, substantial differences can be expected at times across the forecast area. TEMPS should remain uniformly mild mild to warm across the region on Tuesday with highs in the mid 70s for most areas and upper 70s to around 80 over VLD and the eastern FL Big Bend. POPS will range from LIKELY NW to slight CHANCE SE. The front will begin to work its way slowly eastward across the CWA Tuesday night. Temps will remain mild ahead of it with lows in the 50s and 60s. Another round of fog is possible ahead of the front across the eastern zones. On Wednesday, the front will continue its trek across the area, but it will take until evening to clear the Suwannee River. PoPs will range from likely N to chance S. There will be quite a range in temps with S. Central GA and the eastern Big Bend counties getting into the mid to upper 70s once again and those stuck behind the cold front over SE AL and the central FL Panhandle seeing little rise in temps during the day. Depending on frontal timing, areas of light RAIN will come to an end Wednesday night, although the CURRENT forecast allows a slight PoP to linger into Thursday morning. MIN temps will get as low as the mid 30s by around 12Z Thursday over the NW zones with lower to mid 40s to the SE. .LONG TERM (Thursday through next Monday)... The models are now in much better agreement on the timing of the next low pressure system to impact the local region. The 12z ECMWF, 12z Canadian and 00z GFS show the cold front passing through all but our easternmost zones at the beginning of the extended period. By daybreak Thursday the front is forecast to be over or just south of Cross City. Will hold on to a slight PoP across the Big Bend and Valdosta regions Thursday morning to account for the system possibly lingering a bit longer. After the SHORTWAVE and associated cold front pass, additional shortwave energy will rapidly drop to the southeast from the northern plains allowing a trough to dig across the eastern U.S. This will send a dry cold front through the Tri-state area over the weekend bringing with it a re-enforcement of cold dry AIR. Temperatures will be below seasonal levels throughout the extended period with freezing or near freezing min temps possible for Sunday morning.