849 
fxus61 kbtv 211121 
afdbtv 


Area forecast discussion 
National Weather Service Burlington Vermont 
621 am EST Friday Nov 21 2008 


Synopsis... 
unseasonably cold weather is expected to linger across the north country 
through next week. An upper air disturbance will bring a chance of snow 
showers or flurries to the region today through Saturday. Gusty 
northwest winds are also expected across the region on Saturday 
as an intensifying low pressure area moves into the Canadian 
Maritimes on Saturday. A weak ridge of high pressure will build into 
the region on Sunday. A low pressure area moving southeast across the 
Great Lakes on Monday will bring more precipitation to the north 
country next week. 


&& 


Near term /until 6 PM this evening/... 
as of 456 am EST Friday...BUFKIT forecast soundings show a steep 
low level lapse rate will develop across the region today...with a 
chance of snow showers or flurries today...and skies becoming or 
remaining mostly cloudy. GFS MOS maximum temperature guidance for 
today looks too warm...so have gone a few degrees below this 
guidance for maximum temperatures today. 


&& 


Short term /6 PM this evening through Sunday/... 
as of 456 am EST Friday...an upper trough will move through the 
region tonight...with a chance of flurries or snow showers. Have 
gone with a chance of flurries across the valley locations for 
tonight with a chance of snow showers across the higher 
elevations. MOS probability of precipitation for tonight look too high in the valley 
locations where only flurries are expected...so have gone below 
MOS guidance for probability of precipitation tonight in the Champlain and Saint Lawrence 
valleys. 


On Saturday...a low pressure area will move into the Canadian Maritimes. 
This low will bring colder air into the region on Saturday...along 
with gusty northwest winds. Again...will go a few degrees below 
GFS MOS maximum temperature guidance for maximum temperatures on Saturday... 
as this guidance again looks a bit too warm with maximum temperatures 
on Saturday. MOS probability of precipitation again look too high for Saturday...so have 
leaned toward the lower 6 hour MOS probability of precipitation guidance for probability of precipitation on Saturday. 
Some residual flurries or snow showers could linger into early 
Saturday night...before a weak ridge of high pressure builds into the 
region late Saturday night. 


Model guidance showing some lake effect snow showers off of Lake 
Ontario could move into the Saint Lawrence valley and the Adirondacks 
Sunday afternoon...so have gone with slight chance probability of precipitation in these 
areas for Sunday. Have used a blend of the GFS MOS MOS and Eta model MOS for 
maximum temperatures on Sunday. 


&& 


Long term /Sunday night through Thursday/... 
as of 238 am EST Friday...unsettled weather expected for much of the 
extended period. Broad area of high pressure over the Atlantic 
will provide blocking pattern for the NE. On Monday...surface ridge 
still close enough to the East Coast to allow warm front associated 
west/ approaching slow to lift north of area during the day. During 
frontal passage...cold air from overngt will alow precipitation initally to be as light 
snow...then transition into rain shower/SW mix in valley locales as 
southerly winds kick in allowing some warm air advection into the area. Initial 
model probability of precipitation a bit high with bringing surface cold front through the area late 
Monday into Tuesday. Will transition back some...with best chances 
in nny until overngt Monday. Coastl low will form as front mvs 
offshore...then pivot north as it gains strentgh. This is going to 
allow strong easterly flow(bufkit suggests at least 30-45 miles per hour 
potential above 1000-1500ft) to set up over the region through Tuesday. 
West/ temperatures floating near the freezing mark over hir elev of c and east 
Vermont...potential exists for wintry mix(sleet/pockets of Fr 
rain/snow)...before going to mostly rain during the day Tuesday. North New York 
should stay cold enough to keep precipitation all snow and with high quantitative precipitation forecast 
potential...several inches of snow possible. Warm air does not 
reach into all of New York during the day Tuesday. Low will then shift 
ashore and remain over the north country into the end of the 
week...again due to blocking ridge offshore. Will transition rest 
of forecast period over to all -SW for County Warning Area due to cold air wrapping 
in to region as low mvs ashore. 


&& 


Aviation /12z Friday through Tuesday/... 
through 12z Saturday...all forecast sites will see varying cloud 
cover during period...from vfr(bkn-ovc035-045) down to mvfr(bkn015-030) 
at times. Precipitation during period will consist of mainly scattered flurries 
due to low cloud cover...but some bands of -SW through 15z this morning 
and again after 00z Sat may lower visibility to MVFR at times (3-5sm). Winds 
through entire forecast period will be west-northwest 5-10kts west/ some gusts 
around 15-20kt from 12z Friday-00z Sat. Hir terrain will be obscured. 


After 12z Saturday...through Monday...MVFR ceilings over the higher 
terrain with tempo MVFR in the Champlain Valley due to lower ceilings 
and scattered snow showers will be the norm through Saturday. 
Summits should stay obscured during most of this period with 
moist low levels and persistent northwest upslope flow. Sunday could be 
the clearest day with a short wave ridge moving into the area. By 
Monday clouds will increase with some very light snow...but 
visible/ceilings should stay VFR. 


&& 


Equipment... 
due to a local server failure...certain products from National Weather Service 
Burlington will be unavailable...including point and click 
forecasts on the web...and all phone recorded forecasts. 
Technicians are aware of the problem and will work to restore this 
later today. We apologize for any inconvenience. 


&& 


Btv watches/warnings/advisories... 
Vermont...none. 
New York...none. 


&& 


$$ 
Synopsis...wgh 
near term...wgh 
short term...wgh 
long term...jn 
aviation...jn/lahiff 
equipment...