638 
fxus61 kbgm 211927 
afdbgm 


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


Synopsis... 
a moist northwesterly flow of air will keep our skies generally cloudy 
today. On Sunday, an area of high pressure now located over the 
Ohio Valley will build overhead helping to clear out the clouds 
making for a bright end to the weekend. 


&& 


Near term /until midnight tonight/... 
northwest flow combined with a shallow layer of moisture will keep 
area generally cloudy this afternoon with some improvement late. 
Maxes will be around 50. Current forecast in great shape with only 
minor adjacent made. 


The often moisture laden NAM keeps in moisture through tonight 
while the GFS seems to have a better idea by thinning out the deck 
of clouds gradually. The key word tonight will be gradually as 
even the more optimistic GFS does not show drying below the 
inversion until after 06z. 


&& 


Short term /midnight tonight 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/... 
updated as of 101 am...no appreciable changes to the forecast this 
period. 


Model consensus still indicates that the majority of the rainfall 
with the surface wave off the East Coast on Tuesday will stay 
east of the forecast area...so only slight chance probabilities 
look good from this Vantage Point. 


The start of the Holiday period from Wednesday through Friday 
still carries plenty of forecast uncertainty at this time. 
Overall...longer range guidance is leaning towards a slower onset 
of precipitation (more like on Thanksgiving day or Thanksgiving 
night)...with Wednesday mainly dry. The GFS...however...is much 
faster in carrying energy eastward into our neck of the Woods by 
Wednesday...with showers beginning at that point. Given all the 
model discrepancies...won't tinker much with our going 
forecast...which does mention at least a low chance of showers on 
Wednesday. One well agreed upon scenario is that Wednesday and 
Thanksgiving day will continue to feature mild temperatures. 


By Friday...it appears that colder air will begin to filter 
in...as a storm system winds up offshore. This would likely 
result in some lake response...with a good shot of rain and snow 
showers. 


&& 


Aviation /19z Saturday through Thursday/... 
weak northwest flow combined with a shallow layer of moisture will 
keep mainly MVFR ceilings across terminals through middle morning Sunday. 
At ksyr/kelm/kavp, conditions may improve to VFR with ceilings around 
3,500 feet this evening but MVFR ceilings are again likely by the way 08z-12z. 
By middle morning Sunday conditions should improve to VFR with scattered/broken 
clouds around 4k feet. 


Northwest winds around 5 knots becoming light and variable after 
sunset. Light and variable winds on Sunday or light north-northeast. 


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...emh/rrm 
near term...emh/rrm 
short term...mse 
long term...mlj/rrm 
aviation...rrm