645 
fxus62 kcae 231148 
afdcae 
area forecast discussion 
National Weather Service Columbia SC 
648 am EST Monday Nov 23 2009 


Synopsis... 
low pressure along the Carolina coast will move northeast today. High 
pressure will continue to wedge into the Carolinas from the north 
through Wednesday. 


&& 


Near term /until 6 PM this evening/... 
radar at 08z showing rain shield moving mainly north of the area 
early this morning. Models indicate isentropic lift will diminish 
after daybreak. Cold air damming in place so extensive low 
cloudiness with areas of drizzle today. Little change in temperatures 
expected...mav MOS guidance way too warm...met guidance appears better. 


&& 


Short term /6 PM this evening through Wednesday/... 
wedge pattern continues with southwest flow aloft and northeast 
wind at the surface. Shallow moisture trapped beneath a strong 
inversion will hold considerable cloudiness across the area 
through Wednesday. Patchy drizzle or light rain possible at times. 
Models show some uncertainty Tuesday night/Wednesday regarding 
precipitation chances. GFS appears overdone with moisture 
flux/isentropic lift associated with surface wave along coast. Sref 
probability of precipitation much lower although NAM suggests some weak isentropic lift. 
Temperatures likely to remain in the 50s across most of the region 
through Wednesday with soundings showing high relative humidity in 
the lower levels...wedge probably will not break down until 
surface trough moves through Wednesday night. 


&& 


Long term /Wednesday night through Sunday/... 
12z European model (ecmwf) and 12z GFS are in pretty good agreement through Sunday. 
A strong shortwave moves from the Dakotas to the Central Plains 
to deepen the upper low over the central MS valley and Ohio Valley 
through Friday. The surface low over the Great Lakes region slowly 
moves northeast, dragging a cold front across the southeastern 
states on Thursday. Since moisture is limited, expect to see some 
cloudiness but little if any rainfall. More plentiful moisture 
looks to remain south and east of the area and across the central 
Appalachians. Will keep the forecast dry Thursday. 


Large middle and upper level low pressure over the eastern half of 
the country moves off the coast Saturday. Surface high pressure 
building in from the west for next weekend, bringing a cool and 
dry air mass. 


&& 


Aviation /12z Monday through Saturday/... 


High pressure over the Middle-Atlantic States and New England will move 
slowly offshore through today. Meanwhile an area of low pressure 
along the Carolina coast will continue to move northeast. 88d/observation 
indicate some light precipitation occurring across the area...mainly drizzle. 
Observation also indicating most taf sites reporting IFR conditions. 
Anticipate IFR/LIFR conditions for much of the 24 hour taf 
period...with some brief periods of MVFR ceilings/visibilities during the 
afternoon today...with conditions deteriorating by evening into the 
overnight hours. 


Extended aviation outlook...widespread MVFR or IFR conditions will 
continue into early Tuesday and perhaps even into Tuesday 
afternoon/night as a wedge of high pressure continues to linger 
across the region. 


&& 


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


&& 


$$