070 
fxus62 ktae 180028 
afdtae 


Area forecast discussion 
National Weather Service Tallahassee Florida 
825 PM EDT Wednesday Mar 17 2010 


Synopsis... 
00z water vapor and h4 RUC analysis showing a very slow moving but 
amplified upper level pattern across much of the Continental U.S.. main feature 
for our region is the large trough extending from the Southern 
Plains/lower MS valley to the southeast Atlantic coastline. Within 
this trough we find a double closed low structure...with one low 
spinning overtop of our heads...and another pivoting down across 
eastern Texas and Louisiana. 18/00z ktlh sounding showing no lack of 
moisture under this upper low...with a nearly saturated profile 
below 700mb. As this upper level low has moved overhead...almost the 
entire column has undergone a 5-10c drop in temperature. The 850mb 
temperature has dropped to around 2c which is between a 2-2.5 Standard 
deviation from climatology. With this low/middle level cold pool 
forecast to linger overhead through much of Thursday...yet another 
well below normal day in terms of temperature is on tap. 


At the surface...a weak area of low pressure is now exiting eastward 
over the northern Florida Peninsula...and is prognosticated to deepen off 
the Georgia/SC coast later tonight. Weak cold air advection in the wake 
of this low is resulting in a brief ramp up of winds and seas over 
the coastal waters. Have issued a Small Craft Advisory for the 
offshore waters till 400 am as all guidance is in agreement for a 
drop off in the winds during the late night hours. 


Initial lobe of energy is exiting to the east of the forecast area 
this evening taking the main area of synoptic lift with it. Still 
seeing scattered light showers/sprinkles across mainly the northern 
and eastern zones...however this precipitation should not amount to much 
over the next several hours. Therefore outside of a few light 
showers...the overnight period should be rather quiet...albeit cool 
and raw. Temperatures will fall slowly from their early evening "highs" in 
the low/middle 50s (15 to 20 degrees below normal)...to the middle 40s 
by sunrise. 


Closed upper level low to our west will open up and phase with the 
energy overhead during Thursday. Most of Thursday will be dry...but 
with the cyclonic flow aloft and still plenty of available 
moisture...a few scattered showers can not be ruled out. Mostly cloudy 
conditions with a few breaks of sun from time to time can be 
expected. Even with full mixing (which we will not have)...high 
temperatures would only reach the middle/upper 60s. Therefore the Lower/Middle 
60s in the grids look reasonable. 


&& 


Aviation... 
broad deep layered cyclonic flow will keep low clouds and drizzle in 
place through the night for area terminals. Expect ceilings below 
alternate fuel minimums through middle morning Thursday with gradually 
improvement to VFR thereafter. IFR conditions expected at kvld 
through the night and tempo at ktlh...kdhn...and kaby during the 
early morning hours. 


&& 


Marine... 
winds and seas have increased from the northwest early this evening 
in the wake of a departing area of low pressure. This increase in 
winds is expected to be brief in nature with conditions settling 
below advisory levels during the late night hours. Moderate 
northwest winds will decrease further later Thursday into Friday as 
high pressure builds over the northeast Gulf of Mexico. 


&& 


Preliminary point temps/pops... 
Tallahassee 44 65 43 74 44 / 30 20 10 10 0 
Panama City 49 62 49 67 48 / 20 20 10 10 0 
Dothan 44 64 44 74 46 / 20 20 10 10 0 
Albany 42 65 43 75 45 / 50 20 10 10 0 
Valdosta 43 64 43 74 43 / 50 20 10 10 0 
Cross City 45 65 42 73 45 / 40 20 10 10 0 
Apalachicola 49 61 49 66 48 / 20 20 10 10 0 


&& 


Tae watches/warnings/advisories... 
Alabama...none. 
Georgia...none. 
Florida...none. 
GM...Small Craft Advisory until 4 am EDT Thursday for the following 
zones: waters from Suwannee River to Apalachicola Florida from 
20 to 60 nm...waters from Apalachicola to Destin Florida from 20 
to 60 nm. 


&& 


$$ 


Update/marine...mroczka 
aviation...Camp