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fxus62 ktae 231349 
afdtae 


Area forecast discussion 
National Weather Service Tallahassee Florida 
845 am EST sun Nov 23 2008 


Synopsis/discussion... 
(today and tonight) 13z water vapor and h4 RUC analysis showing a 
rather complex upper level pattern over North America this morning. 
Two large upper lows spinning across west-central Canada and over 
eastern Quebec are the dominant steering mechanisms for the northern 
stream. This flow dives into shortwave energy moving into the upper 
plains states around the southern periphery of the first mentioned 
upper low. The flow then briefly ridges up through the upper 
MS/valley and Great Lakes states before diving southeast to the 
middle-Atlantic around the southern periphery of the eastern Canadian 
upper low. Abundant southern stream moisture is also seen on WV 
imagery streaming northward from the Baja California peninsula into the 
Southern Plains. This middle-upper level moisture will help fuel the 
evolution of the shortwave currently approaching the upper plains as 
it amplifies into the MS valley during Monday. 


In the lower levels...surface ridge axis extends from the Carolina 
coast southwest into the forecast area keeping the gradient relaxed. 
With the ridge axis in place and combined with dry low levels... 
early morning temperatures were able to drop into the upper 20s to 
middle 30s over a large portion of the region before increasing 
middle-level clouds expanded southeastward and disrupted the 
radiational cooling process. This middle-level deck is resulting from a 
zone of low level warm advection to our west and characterized by a 
rather impressive ridge of isentropic upglide along the 290-300k 
surfaces. Regional radars are indication some light showers/drizzle 
falling out of this middle-level deck over southeast Alabama and southwest 
Georgia...however with surface dewpoint depressions between 10 and 
15 degrees...would not anticipate any measurable rainfall reaching 
the surface. GFS/NAM is agreement showing this feature slowly 
weakening through the day while keeping the resulting lift and best 
cloud coverage over the northwest half of the area. 


With the sun now up...temperatures are on the rise area-wide. Under 
the partly to mostly cloudy middle-level deck over the northwest zones temperatures 
will be a bit cooler topping out in the upper 50s to near 60. 
Further southeast under partly sunny skies...afternoon highs should 
easily reach the lower and middle 60s. 


Surface ridge will still be in control of the area tonight...however 
it will be weakening. Easterly flow will be slowly coming around to 
the southeast with time allowing for a steady increase in low level 
moisture. This moisture advection combined with at least partly 
cloudy skies should result in a much warmer overnight period than 
has been experienced the past several night. In fact low 
temperatures tonight should bottom out in the lower 40s for the 
coldest locations with upper 40s and lower 50s along the coast from 
Franklin County to the Florida Panhandle. 


&& 


Marine... 
surface high pressure remains to our northeast through the next 24 
hours while slowly weakening its influence on the marine area. Winds 
expected to continue from the northeast in roughly the 10 to 15 knot 
range although expect winds to decrease during the afternoon over 
Apalachee Bay to the 5 to 10 knot range. Seas remain in the 2 to 3 
foot range away from the coast. As the high weakens overnight should 
see the flow come around to the east and southeast. A cold front 
will then approach from the west on Monday crossing the forecast 
waters Monday night and Tuesday morning with a sharp wind shift to 
the north. A period of advisory level winds is possible Tuesday and 
Tuesday night in the wake of this front before high pressure builds 
south toward the area Wednesday and Thursday. 


&& 


Aviation... 
VFR conditions expected to prevail into the evening hours. Band of 
middle-level ac between 6 and 12kft continues to slowly progress 
southeast across the area and will be the main aviation concern over 
the next 12 hours. A few sprinkles can not be ruled out with this 
band of clouds...especially from kdhn to kaby and especially this 
morning. However...with fairly dry low levels still in place...any 
precipitation that does reach the surface should be very light and 
measurable rainfall is not expected. 


&& 


Fire weather...aside from the potential for brief 1 to 2 hour 
durations of relative humidity less than 35 percent in well inland North Florida 
this afternoon...critical relative humidity values are not expected until Tuesday 
afternoon. The combination of an incoming dry airmass and windy 
conditions may allow red flag criteria to be met Tuesday afternoon 
in portions of North Florida. This will continue to be monitored. 


&& 


Preliminary point temps/pops... 
Tallahassee 63 42 68 50 66 / 0 0 20 30 05 
Panama City 63 48 68 54 65 / 0 0 40 40 05 
Dothan 57 44 64 47 64 / 0 0 60 40 0 
Albany 58 40 64 47 64 / 0 0 40 40 0 
Valdosta 61 42 68 48 65 / 0 0 10 30 05 
Cross City 68 43 74 51 69 / 0 0 05 20 20 


&& 


Tae watches/warnings/advisories... 
Alabama...none. 
Georgia...none. 
Florida...none. 
GM...none. 


&& 


$$ 


Fire weather...Gould 
rest of discussion...mroczka