955 
fxus61 kbgm 212346 
afdbgm 


Area forecast discussion 
National Weather Service Binghamton New York 
646 PM EST Sat Nov 21 2009 


Synopsis... 
a moist northwesterly flow will keep our skies generally cloudy 
overnight. High pressure will build over the region on Sunday 
making for a partly to mostly sunny afternoon. Fair weather will 
continue through much of Monday as high pressure gradually moves 
northeast into Nova Scotia. 


&& 


Near term /until 6 am Sunday morning/... 
abundant low level moisture trapped under a subsidence inversion 
will result in cloudy skies for the overnight period. With light 
northwest flow conditions will be slowest to improve across the 
upslope areas primarily the Susquehanna region with the lake 
plain and NE PA seeing improving conditions possibly toward 
daybreak. 


With overcast skies went several degrees above MOS guidance, 
basically middle to upper 30s, with temperatures around 40 in the lake plain. 


&& 


Short term /6 am Sunday morning through Tuesday/... 
light northerly flow associated with high pressure over Quebec 
will bring dryer air south across the area on Sunday. Left over 
clouds trapped beneath the inversion Sunday morning should 
dissipate in most areas by afternoon as dry air filters in. Some 
light downslope south of the Adirondack Mountains will aid the 
clearing early Sunday in the Mohawk Valley. 


Quiet weather will continue on Sunday night into Monday with clear 
skies and continued above normal temperatures. GFS/NAM/ECMWF and 
Gem are all in agreement that the next chance for precipitation 
will be late Monday into Tuesday as a weak wave of low pressure 
moves up the middle-Atlantic coast toward New England. This morning's 
sref's indicate a 50 to 60 percent chance for some light rain with 
this wave Monday night into Tuesday... with the highest chances 
over northeast PA. Based on this have edged probability of precipitation up from low chance 
to high chance during that period. 


&& 


Long term /Tuesday night through Saturday/... 
today/S medium range models are all over the place during this 
period. HPC favors a European model (ecmwf)/ensemble blend and will thus strictly 
follow their guidance with only minor modification. These solutions 
suggest that a deep trough will move out of the central US during the 
Wednesday-Thursday time frame and gradually move through the east Fri-Sat. 
Initially the trends look a little slower than earlier models...and 
have trimmed back probability of precipitation for Tuesday night before allowing chance probability of precipitation to 
cover the rest of the week due to high level of uncertainty. 
Cny/nepa remains on the mild side of the system with mainly rain as 
the ptype. Then the air looks to become cold enough on northwesterly flow Friday 
night and Saturday for potential les. To account for this...we have 
increased precipitation chances above guidance over the lake prone 
vectors from 270-300 degrees. 


&& 


Aviation /00z Sunday through Thursday/... 
an expansive shield of low-level clouds exists across the area this 
evening as moisture remains trapped below a a layer of warm air 
aloft. All indications suggest MVFR...and possibly some embedded 
IFR ceilings will dominate through the remainder of the overnight 
period with improvements likely after 15z. Current thought is that 
kelm/kbgm will be the most susceptible for IFR ceilings as well as 
kith due to weak northwesterly flow off of Cayuga Lake. For the 
time being...not overly concerned about visibility restrictions despite 
high amounts of low-level moisture as the cloud deck already in 
place should limit to a large degree the amount of nocturnal 
cooling. Trends will have to be monitored however. Clearing skies 
and weak northeasterly winds will dominate through the conclusion 
of the forecast period with high pressure firmly in place. 


Outlook... 


Sun ngt/Monday...VFR. 
Monday ngt/Tuesday...MVFR possible in showers. 
Tuesday night through Wednesday night...VFR. 
Thursday...MVFR in showers. 


&& 


Bgm watches/warnings/advisories... 
PA...none. 
New York...none. 


&& 


$$ 
Synopsis...rrm 
near term...rrm 
short term...mse 
long term...jab 
aviation...cmg