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Area forecast discussion 
National Weather Service Tallahassee Florida 
215 PM EDT Friday Jul 18 2008 


..drier and warmer weekend on tap for local area... 


Synopsis... 
at 2 PM EDT..it was mostly sunny across the local area. Temperatures ranged 
from around 90 north to middle 90s closer to the coast. Winds were 
variable 5-10 miles per hour. 


At upper levels... 
looking at the big pictures...Summer time pattern continues to dominate 
highlighted in northern stream by westerlies near US/Canadian border with 
several shortwaves embedded in flow. Main activity will follow from 
large scale trough/closed low developing over British Columbia with 
downstream waves...Montana and in ont north of Lake Superior. In between... 
persistent upper ridge central rockies to southern Appalachians. Over southern 
stream... flat ridging over much of the southern Continental U.S. Except for 
low over Southern California...a weak ridge over the 4 corners...a relatively 
small low near the East Texas Gulf Coast..a deep layer low off the southeast Georgia 
coast and another low over the Bahamas. 


At lower levels... 
latest surface analysis showed a weak 1013 mb low about 40 miles 
east of the coast of south/central most Georgia. Associated trough extends from 
low SW to across NE fla/Georgia border. Per jax radar...convergent rain 
bands reaching East Coast of Florida with deep convection only on east side. 
12z regional soundings with pronounced east-west moisture gradient. I.E. 
Jax closest to low with 2.16 precipitable water...followed by tae 1.92 precipitable water...ffc 
(atl) with 1.31 precipitable water and bmx with 1.23 precipitable water. Latest NHC two product 
indicates that surface pressures falling steadily and system may 
become more favorable for development into a depression next 48 hours. 


South of low...high pressure remains centered over the middle-Atlantic 
stretching S/SW into the NE Gulf with a typically flat pressure 
gradient. A pocket of dry air was nosing down from north Georgia to the 
Florida Panhandle on the backside of this low. The latest numerical 
guidance takes the low slowly north northeastward placing it off the Carolina 
coast on Saturday morning...continuing slowly northward along the East 
Coast and to the New England area by Monday. 


In its wake...E-W deep layer ridging builds over the NE Gulf region 
through the weekend with decreasing precipitable waters  and precipitation mainly shallow sea 
breeze induced precipitation. Warm temperatures aloft due to subsidence 
will tend to inhibit convection through short term with daytime 
temperatures running a few degrees above climatology. By early week..the 
ridge weakens as next upper trough develops and moves eastward and a cool 
front moves into Georgia/ala midweek. The active Caribbean tropical wave 
will have very minimal effect on rain but should lead to a return 
of a low level light and variable or onshore flow which should 
persist through the early work week 


&& 


Short term...tonight through Monday 
a dry pattern setting through short term with any precipitation associated with 
shallow sea breeze...mainly across Big Bend. 


Tonight...a few showers are possible eastern most zones. Otherwise... 
patchy light fog possible late tonight...especially if there is any 
residual moisture in eastern zones. Inland pre-dawn lows around 70. 


Saturday through Monday... 
as the deep layer ridging develops...expect the 1000-700 mb steering 
flow to become light and variable especially beginning on Sunday. 
This usually allows the Florida Big Bend and Panhandle sea breeze fronts 
to propagate slowly inland. However limited deep layer moisture will 
keep rain chances below climatology at or below 20 (except 30 percent 
eastern Big Bend and adjacent ga). Maximum/min temperatures will be close to 
average...middle 90s and around 70. The unusually Low Cape and weak 
vertical Theta-E gradient will reduce the threat of pulse severe 
storms today. 


Long term... 
(monday night through friday) the upper pattern will become more 
amplified as a ridge builds out west and a trough digs down the 
eastern Seaboard. At the surface... high pressure will ridge 
across the Gulf from the western Atlantic through middle week and 
then break down as a cold front approaches from the north. The 
front is forecast to push into North Florida on Friday with drier 
air entering our Alabama/Georgia zones. We can expect below normal probability of precipitation on 
Tuesday due to deep layer ridging...followed by climatology or slightly 
below climatology probability of precipitation Wednesday into Friday. Of interest during this 
period is a possible tropical system in the southwest Gulf. The gfsx 
tracks it west northwest toward south Texas. 


&& 


Aviation...VFR conditions are expected through tonight. With the 
low center and higher moisture well east of the area, will include 
vicinity rain showers at kvld this afternoon. Prevailing winds will be northerly less 
than 10 kts, except shifting to a westerly direction at kpfn with the 
afternoon sea breeze. With near calm winds and mostly clear skies 
overnight, there is the potential for a brief period of radiation 
fog with MVFR visibilities at the terminals during the pre-dawn hours on 
Saturday. 


&& 


Marine... 
winds and seas will remain low through the weekend as a surface 
ridge builds over the region. If the tropical wave (currently 
moving quickly west through the caribbean) develops like the 
global models suggest...there could be a slight bump in the 
southerly swell here by middle week. 


&& 


Fire weather... 
although drier air moving in...critical relative humidity should remain above 
red flag levels through at at midweek. 


&& 


Preliminary point temps/pops... 
Tallahassee 72 93 71 94 / 10 20 10 20 
Panama City 76 91 76 91 / 10 20 10 20 
Dothan 72 95 73 93 / 0 10 10 10 
Albany 72 96 73 95 / 10 20 10 10 
Valdosta 71 95 71 95 / 20 30 10 20 
Cross City 71 93 72 93 / 20 30 10 20 


&& 


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


&& 


$$ 


Fire wx/aviation...jamski 
public/marine...block 
long term...Barry 

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