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fxus61 klwx 221555 aaa 
afdlwx 


Area forecast discussion...updated 
National Weather Service Baltimore Maryland/Washington District of Columbia 
1055 am EST Sat Nov 22 2008 


Synopsis... 
high pressure will build into the middle Atlantic this weekend. A 
cold front will move across the area on Monday. Low pressure in 
the upper levels of the atmosphere will remain over the northeast 
portion of the country through late week. 


&& 


Near term /until 8 PM this evening/... 
dry...cold and windy. Northwest flow shifting to more westerly though winds are 
again picking up across the northeast and middle Atlantic. A surface Lee 
trough axis lined up over the shndoh valley has winds turned westerly and 
the intense upper jet has influence through the column...keeping 
strong winds down into the boundary lay. Minor veering of the profile 
in the boundary layer west/ relatively decent amount of moisture in the low 
levels...but very dry at the surface. Wind gust this afternoon exptd in the 
20-30mph range across much of the area...espc much of Maryland and Nova 
/lesser effect S toward cho/. 


The steady west-northwest winds from the exiting cold upper trough axis will 
keep temperatures from reaching 40 across much of the area east of the Blue 
Ridge. Even if temperatures do reach that mark...it wont feel like it. 
Wind chills are exptd to remain steady in the M/u20s this 
afternoon. 


Lake effect machine not through yet. A more westerly component to the 
onshore Lake Erie winds have directed snow bands due southeast. Portions 
of the tail ends now making it across the Mason-Dixon line west/ only 
isld flurries exptd for the nrnmost zones late this morning through 
early afternoon. 


&& 


Short term /8 PM this evening through 6 am Sunday/... 
high pressure at the surface builds into the middle Atlantic tonight. 
Initially there may be some middle to high clouds but these should 
start to scatter out overnight. Advection will have waned...but 
radiation will take over and promote a colder night tonight. This 
will especially be the case if skies clear overnight. Snow pack in 
the far western County Warning Area was also considered for min T. 


&& 


Long term /Sunday through Friday/... 
another strong short wave trough is forecast to dig southeastward from central Canada 
into the northern middle Atlantic Monday. This system is forecast to evolve into a Deep 
Cut off low over the northeast Tuesday and meander over the northeast 
states through the end of the new work week. At the surface...moisture 
will surge northward into area Monday afternoon ahead of a cold front. Front will 
clear the area Monday night while another area of low pressure forms near 
NYC/Long Island. Rain is expected to be main precipitation type although a 
rain/snow mix is still possible over the higher elevs Monday afternoon. 
Lake enhanced snow showers will intensify on Tuesday as low-level winds 
strengthen. Low-level trajectories are expected to be from the west 
rather than northwest with no connection from Lake Erie which should tend 
to limit snow totals somewhat. Too early to issue any potential 
watches and/or advisories. Also...winds over the higher elevs on 
Tuesday could flirt with advisory criteria. 


&& 


Aviation /15z Saturday through Wednesday/... 
another day of gusty west to northwest winds today...although not 
quite as gusty as yesterday and gusts will abate after sunset. 
Snow flurries and squalls should stay to the north in 
Pennsylvania...allowing visual flight rules at all terminals 
during the valid taf period. 


MVFR conditions possible Monday afternoon and night. Gusty 
west winds Tuesday and Wednesday. 


&& 


Marine... 
gradient will remain tight for gusty winds over the marine waters 
through the day...W/ a gradual slackening drng the late afternoon and 
early evening hours...from an area of high pressure from the west. 
Gustiest of the winds will be across the lower Potomac and Middle 
Bay /btwn 25-30 kt/...then 20 to 25 knots will be more common this 
afternoon. Expect gusts to fall below Small Craft Advisory 
criteria over the upper Potomac by 03z...however 20 knots gusts may 
persist over the lower Potomac and Bay through the night and that 
headline will stretch out until 09z as inherited. 


Small Craft Advisory conditions returning Monday afternoon and persisting at least 
into Wednesday. 


&& 


Lwx watches/warnings/advisories... 
District of Columbia...none. 
Maryland...none. 
Virginia...none. 
WV...none. 
Marine...Small Craft Advisory until 4 am EST Sunday for anz530>534-537. 
Small Craft Advisory until 10 PM EST this evening for anz535- 
536. 


&& 


$$ 
Update...gms 
marine...peloquin/Rosa