Weather

669 
fxus61 kaly 060912 
afdaly 


Area forecast discussion 
National Weather Service Albany New York 
412 am EST Tuesday Jan 6 2009 


Synopsis... 
high pressure will weaken today and shift eastward off the coast 
this evening. An area of low pressure will approach from the 
southwest today and will move across the Ohio Valley tonight...and 
into the Great Lakes region Wednesday. A secondary area of low 
pressure will develop near Long Island Wednesday. The lows will 
head northeast Wednesday night. The the coastal low will eventually 
become the dominate low Thursday as its head into the Canadian 
Maritimes. The combination of these lows will result in a complex 
weather situation that will bring snow...sleet and freezing rain 
to the region beginning Tuesday evening. 


&& 


Near term /through tonight/... 
ridge over region will weaken and shift eastward today and this 
evening. The model maintain dry weather for today with precipitation 
holding off until after 6 PM. 


Another very complex storm with phasing of streams. Similar to 
storms from last winter where do not quite reach snow criteria or 
ice criteria for a warning but have a high impact storm. A low 
pressure system approaches from southwest with overrunning 
precipitation overspreading region this evening as its associated 
warm front approaches. Will be cold enough for all snow through 
the evening. Warmer air will move into aloft over cold air at the 
surface setting the for freezing rain and sleet. Overnight the mix 
and change over will occur south of the capital district. Big 
concern is that the there is sub tropical connection of moisture 
into the system which can be seen on water vapor. Have moisture 
streaming up from the Baja California of California. Could mean more freezing 
rain. Concerned about potential ice accumulation. Have enough 
confidence to go with Winter Storm Warning for south of the 
capital district and will maintain watch across rest of forecast 
area at this time. Approach warnings and advisories will be issued 
later today. 


&& 


Short term /Wednesday through Thursday night/... 
coming soon 


&& 


Long term /Friday through Monday/... 
Friday will get off to a cold start...with lows near zero north 
to the middle teens south...with a shroud of lake and terrain 
enhanced cloudiness covering much of the forecast area from 
the capital district north and west...the result of Canadian 
air picking up moisture off lakes Huron and Ontario. Winds will 
slacken some as high pressure builds over the region...but 
temperatures will struggle to make it into the middle teens across 
the Adirondacks...and into the low and middle 20s in the Hudson... 
Mohawk...and Housatonic valleys. Clouds will increase Friday 
night as a low pressure system moves from the northern plains to 
the Great Lakes region and brings a flow of relatively warm and 
moist air from the Gulf states into the region against the 
cold air mass...resulting in the possibility of some light snow 
Friday night and Saturday and lingering Sunday with some lake 
enhancement as the upper low slowly makes its way to the 
Maritimes. That in turn will again open the icebox door and 
usher in even colder air Sunday and Sunday night. The 
temperature Sunday will struggle to make it into the upper 
teens in the Albany area...with highs in the single digits 
across the Adirondacks and higher elevations of the Green 
Mountains of southern Vermont. With a very dry air mass 
temperatures will plummet Sunday evening and night...with 
lows Monday morning well below zero across the Adirondacks 
..near zero in the capital district...And only in the 
single digits as far south as the middle Hudson region of New 
York and southern Litchfield County Connecticut. At this point 
we are probably looking at an advisory amount of snow although 
the fluff factor with the cold temperatures will probably make 
it higher...especially north and west of Albany. The good news 
is at this time it appears to be an all snow event without any 
rain or sleet. An Arctic high briefly drops into the region 
Sunday night and early Monday...but quickly moves east as 
another surface low moves from the Canadian prairies across 
the Great Lakes resulting in the possibility of some more 
snow across the region starting Monday night. 






&& 


Aviation /06z Tuesday through Saturday/... 
winds have slackened at kalb and were light from a generally 
westerly direction across the region. A plume of stratocu extended 
from Lake Ontario across the Adirondacks and at times was resulting 
in a 4000 feet ceiling at kgfl. A few wisps of it were noticed at kalb 
but for the most part skies across the middle part of the forecast 
area were clear. Farther south...high clouds associated with a 
low over the Tennessee Valley and its associated warm front 
covered the southern part of the forecast area with bases above 
fl150. A local situation has at times reduced the visibility at 
kgfl to IFR...but otherwise conditions were VFR across the 
forecast area and will remain so well through this afternoon. 


Conditions will start to deteriorate this evening with MVFR 
visibility due to snow and ceilings lowering to around 3000ft 
at kpou by around midnight. They are likely to deteriorate to 
IFR later tonight as ceilings lower and heavier snowfall 
reduces visibility...with the snow mixing with and turning to 
sleet/freezing rain south of kalb. 


Outlook... 
Wednesday...IFR vsby/cig. Sn/pl/fzra. 
Wednesday night...slow imprvmt to MVFR precipitation becmg all snow. 
Thursday...MVFR...cig. Chance -shsn. 
Friday...VFR...no sig weather. 
Sat...VFR/MVFR...chc -shsn. 


&& 


Hydrology... 
no hydrology related problems are expected through the week. 


A storm system is expected to bring a wintry mix of precipitation to 
the area Tuesday night and Wednesday. Temperatures are forecast to 
remain cold enough so that melt...and resulting runoff...should be 
insignificant. Models indicate that cold weather will persist into 
next week. Temperatures may be cold enough across the Adirondacks 
and southern Vermont Sunday through Tuesday for some isolated freeze 
up river ice jams to form by Tuesday. Elsewhere....river ice will 
form and thicken. 


Snow water equivalent data from field surveys is expected this week. 
Our initial 08-09 winter Spring flood potential outlook will be 
issued on Friday Jan 9th. 


For details on the rivers...please visit the advanced hydrologic 
prediction service /ahps/ graphs on our website. 


&& 


Aly watches/warnings/advisories... 
CT...Winter Storm Warning from 7 PM this evening to 7 am EST 
Thursday for ctz001-013. 
New York...Winter Storm Warning from 7 PM this evening to 7 am EST 
Thursday for nyz058>061-063>066. 
Winter Storm Watch from this evening through Thursday morning 
for nyz032-033-038>043-047>054-082>084. 
Massachusetts...Winter Storm Warning from 7 PM this evening to 7 am EST 
Thursday for maz001-025. 
Vermont...Winter Storm Watch from this evening through Thursday morning 
for vtz013>015. 


&& 


$$ 
Synopsis...iaa 
near term...iaa 
short term... 
long term...rck 
aviation...rck 
hydrology...dirienzo 

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