391 
fxus62 kcae 181826 
afdcae 


Area forecast discussion 
National Weather Service Columbia SC 
226 PM EDT Friday Jul 18 2008 


Synopsis... 
an area of low pressure off the southeast Georgia coast will drift 
northeast tonight and Saturday...and push east of our region 
Sunday. 


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Near term /through tonight/... 
low pressure center currently located just offshore southeast Georgia coast. 
Current dewpoints across our forecast area are running about 10 
to 15 degrees higher than at this time yesterday. Laps analysis 
indicating weak to moderate instabilities. Radar indicating band 
of showers across our east/southeast forecast area...pushing inland. Will expect these 
showers to gradually dissipate as it encounters drier air across 
our northwest forecast area. Will maintain shower chances east/southeast forecast area through tonight. 


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Short term /Saturday through Sunday/... 
NHC indicates some possiblity that the low offshore could develop 
into a tropical cyclone. Models have the low pressure area moving 
to the NE. NAM keeps the center offshore...while GFS/Canadian 
appear to move the low up the SC coast and inland into eastern NC. 
Either way...it appears that the center and most of the 
precipitation will remain generally to the south and east of our 
forecast area. Winds Sat/sun will be influenced by the track of the low and 
extent of any intensification. After coordination with adjacent 
offices...wind grids were populated with the NAM model...with some 
adjustments...through Sunday. By Sunday...it appears that the low 
will be to our east. A dry flow on the back side of the low 
appears will preclude convection Sunday. 


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Long term /Sunday night through Friday/... 
models indicate upper trough along the East Coast Monday with northwest 
flow aloft over our region. Relatively dry air to keep probability of precipitation down 
Monday. Expect gradually increasing atmospheric moisture during the 
week...but some building heights aloft could keep probability of precipitation down. A 
surface boundary may come down by Wednesday/Thursday time frame. Will 
generally go 20 to 30 probability of precipitation for diurnal convection during most of 
the period. 


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Aviation /18z Friday through Wednesday/... 
a low pressure system off the South Carolina coast will move slowly 
northeast overnight. Bulk of showers should remain east of taf 
sites. However...radar and models suggest bands of showers will 
continue to move west from the coastal areas into the midlands 
through the early evening. Expect a broken cumulus deck most areas 
with scattered showers mainly east of Columbia. So will put in 
showers in the vicinity at tafs...cae/ogb. These showers should not 
affect visibility and any rain should be brief. Clouds should 
diminish during the evening...especially csra where airmass drier. 
Models suggest stratus will develop after midnight as low level 
moisture increases...less threat csra. This will result in MVFR most 
areas toward daybreak. Low clouds should mix out after sunrise. 




Extended outlook...chances of restrictions to ceilings/visibilities depend on 
the movement of the low off the Georgia coast...with the best chance 
of those restrictions being Saturday. May see scattered diurnal 
showers and storms Sunday and Monday. 


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Cae watches/warnings/advisories... 
SC...none. 
Georgia...none. 


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$$