402 
fxus61 kakq 082020 
afdakq 


Area forecast discussion 
National Weather Service Wakefield Virginia 
320 PM EST Thursday Jan 8 2009 


Synopsis... 
a secondary cold front pushes off the coast this evening. High 
pressure will build into the region tonight through Friday...then 
move off the coast for Friday night into early Saturday. The next 
cold front pushes across the area late Saturday into Saturday 
night. High pressure returns for Sunday into Monday. 


&& 


Near term /until 6 am Friday morning/... 
colder air mass set to arrive overnight as middle level trough exits CST...and 
deep layered northwest flow takes control. Decent clearing trend across forecast area so far 
this afternoon...W/ area of cloudiness about to exit eastern NC...and widespread SC 
generally limited to the mountains most of SC across forecast area at this time expeceted to dspt 
overnight...lvg generally sky clear for most plcs. Not xpctg low level winds to 
dcpl...remaining (at least) brzy this evening...W/ spds slow to decreases from 
inland to CST overnight. Low temperatures mainly M/u20s to l30s. 


&& 


Short term /6 am Friday morning through Sunday night/... 
surface hi pressure builds into the region by Friday afternoon...then shifts offshr for 
Friday night into Erly Sat. Low level flow will be slow to swing to the S 
Friday afternoon...limiting any wrmup. Higher level moisture from warm air advection developing in vicinity of 
southern lakes region spreads into the forecast area from the northwest by afternoon hours. So...the 
day begins sny...then becomes psny for most plcs. Hi temperatures will be in 
the l/m40s north...M/u40s S. 


Xpctg quik drop in temperatures Friday evening...b4 rdgs level off...as surface hi 
pressure slides offshr. Surface low pressure tracks through the Ohio River valley Friday 
night...W/ xtsv cloudiness extending eastward across northern mdatlc region. Will have p/mcldy 
north...clr/pcldy S...W/ low temperatures from the m20s to l30s. 


Surface low pressure continues moving eastward near the Mason-Dixon line Sat/Sat evening. 
Trailing cold front pushes into forecast area late Sat...then off the CST after 
mdngt Sat night. Blended model probability of precipitation (though NAM about 3-6 hours sloer west/ 
frontal passage)...boosting to 40-60%. Drying from the northwest lt Sat night 
through sun...though clearing...especially closer to CST...may be mr gradual due 
to low level flow from the north and low level cold air advection over "wrmr" waters. Low temperatures Sat 
night in the 30s/l40s...hi temperatures sun from u30s/around 40 north to m40s S. 


&& 


Long term /Monday through Thursday/... 
high pressure looks to remain in control for the beginning of next week 
west/ fairly benign weather and cooler low temperatures in the 20s to low 30s...and 
highs in the 40s. Models still indicating that a weak trough will swing 
through from the northwest on Tuesday. This feature appears to dry as it mvs over 
the mountains...so decided to keep probability of precipitation low at 20-30% (higher over the northern 
half of forecast area.) Colder air is prognosticated to arrive later in the week. 
There is great uncertainity with pattern after the medium range..with 
Euro/GFS showing dramatically diff solutions. 


&& 


Aviation /20z Thursday through Tuesday/... 
VFR through the taf cycle. Cold front passing through the region 
Erly this afternoon. Some -ra/virga may occur over southeast Virginia/NE NC this afternoon 
with passage but do not foresee any visibility problems at surface. Look for 
wind gusts of 30 to 35 kts for a few hours as front passes. Winds 
subside overnight to at or below 10 kts for most locations. Winds shift to 
the north...which will lead to orf winds to increase off the Bay 
overnight...but held gusts near 20 kts (could see stronger gusts 
for a few hours). Winds shift more to the northwest twrds 09/10z ending 
gusts. 


VFR conds continue on Friday as high pressure mvs into the area. 
Clouds expected to increase on Sat however as the next system 
approaches...with precipitation possible Sat afternoon. 


&& 


Marine... 
pressure gradient continues to relax into this evening as the surface 
low mvs NE and surface high pressure from the west mvs into the region. 
However...Small Craft Advisory conds expected for all areas through Friday morning until the 
upper trough mvs thru(and offshore) and high pressure begins to build 
in over the region in earnest. 


Another system will approach the waters on Saturday...and looks to 
again increase winds into Small Craft Advisory range by midday. This front mvs east 
of the waters by Sunday morning however...with winds diminishing below 
criteria by late aftn/evng. 


&& 


Akq watches/warnings/advisories... 
Maryland...none. 
NC...none. 
Virginia...none. 
Marine...Small Craft Advisory until 11 am EST Friday for anz630>633-650- 
652-654-656-658. 


&& 


$$ 
Synopsis...alb 
near term...alb 
short term...alb 
long term...smf 
aviation...ccw 
marine...smf