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Area forecast discussion 
National Weather Service Wakefield Virginia 
356 am EDT Wednesday Aug 20 2008 


Synopsis... 
a back door cold front will drop south of the area this morning...as 
high pressure builds in from the north. The high will slide off 
the New England coast Thursday afernoon...and remain in control into 
the weekend. 


&& 


Near term /until 6 PM this evening/... 
the backdoor front will drop S of the area this morng...with hi 
pressure bldng in from the north for the remainder of the day. Expecting scattered 
cumulus or ac across most of the region...so generally mostly sny sky. 
More comfortable temperatures today...with surface winds from the NE or east. Rdgs in 
the lower to middle 80s most places. 


&& 


Short term /6 PM this evening through Friday/... 
surface hi pressure just to the north-northeast of area tonight. Could be a few more clouds 
over southern/SW cnties due to low level moist from on shore flow. Othrwise...mostly 
clear sky with min temperatures in the upper 50s to middle 60s most places (lwr 
50s sby). 


The hi will slide off the New England CST Thursday afternoon and be in 
control through at least Friday. Prtly to mostly sny both days...with Erly 
surface flow keeping maximum temperatures in the lower to middle 80s. On shore flow/weak 
disturbance combination could produce isolated rain showers over extreme southern 
cnties during Friday. 


&& 


Long term /Friday night through Tuesday/... 
high pressure centered off of New England will nose down into the 
middle Atlantic Friday night through Saturday night. High temperatures will 
be in the Lower/Middle 80s along the coast under easterly flow...with upper 
80s farther inland. 


The 12z run of the GFS moves a stronger and deeper trough towards 
the region later Sunday through late Monday...while the European model (ecmwf) 
shows a weaker and more shallow trough remaining to our north. If the 
GFS scenario occurs then the remnants of Fay could be drawn 
towards our area by Tuesday if the trough digs far enough to the 
S. Will stick with persistence (close to HPC/European model (ecmwf) guidance) for 
now until more model run to run consistency occurs...with only a 
slight chance of diurnally driven precipitation included for each day in 
the extended. High temperatures will be 85 to 90 Sunday and Monday...with 
lower to middle 80s on Tuesday due to increasing cloud cover. Low temperatures 
will range from the middle 60s in the Piedmont up to the lower 70s near 
the beaches. 


&& 


Aviation /08z Wednesday through Sunday/... 
much drier airmass filtering in behind the front this morning...a 
good 10 degree or so drop in dew points behind this feature will keep 
fog at Bay. Ecg will see a few hours at the start of this taf period 
with fog however until front makes it through. For the rest of the 
day...just some scattered middle cloud across the area associated with 
front...and a few sites (mainly orf/phf and ecg) may see some gusts 
up in the 18-20kt range this afternoon. Not that confident in this yet 
however so have just put 12kts in tafs for now. Will re-evaluate for 
next set of tafs. 


High pressure moving north of the area will keep weather relatively quiet 
for the next several days. 


&& 


Marine... 
with front currently moving through...winds are shifting around to the 
north and picking up pretty rapidly. Have decided to go with Small Craft Advisory 
flags for all locations today as gusts are well within Small Craft Advisory range and 
should continue to be gusty throughout much of the day. Speeds begin 
to subside late this evening and all flags are dropped just after 
midnight tonight. 


Winds remain easterly through the start of the weekend (with speeds 
10-15kts or less) with high pressure moving north of the area. 


&& 


Akq watches/warnings/advisories... 
Maryland...none. 
NC...none. 
Virginia...none. 
Marine...Small Craft Advisory until 2 am EDT Thursday for anz632-633- 
654-656-658. 
Small Craft Advisory until 8 PM EDT this evening for anz630- 
631-650-652. 


&& 


$$ 
Synopsis...tmg 
near term...tmg 
short term...ccw/tmg 
long term...jrl 
aviation...jym 
marine...jym