Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
1242 PM EST Monday Jan 26 2015
low pressure to the Lee of the mountains in Virginia and North
Carolina will redevelop off Cape Hatteras later today...then slow
track to the east of Long Island by Tuesday morning...and east of
Cape Cod by Wednesday morning. This storm will bring a crippling
blizzard to Litchfield County and heavy snowfall to the remainder of
adjacent western New England and much of eastern New York. To the
west of the Hudson Valley...snow accumulations will be moderate.
Near term /through tonight/...
the winter storm watches for northern Warren County...as well as
Fulton County and Montgomery counties have been downgraded to winter
All other headlines of winter storm warnings (and the Blizzard
Warning from Litchfield county) remain the same...1pm today through
The only update with this issuance was to make some minor
modifications to the probability of precipitation and weather grids for today.
Initially...some light snow will attempt to March north into areas
south of the capital region. Meanwhile...high pressure from eastern
Canada will continue to crest southward so if anything...dry air
will initially win out...keeping most of the light snow south of the
Mohawk River through midday or even much of the afternoon...with
maybe a few flurries further north.
It will be cold day with little or no sunshine...so temperatures
will be mainly confined to the teens from the capital region
northward...around 20 to the south of Albany.
The 06z GFS and especially 06z NAM actually increased the quantitative precipitation forecast
compared to the 00z runs of each. The 00z runs were pretty light
from Albany north and west. The 06z runs...while not quite as heavy
as older guidance maybe signaled a trend to heavier amounts again.
It will all depend on how far westward the deformation band can get.
It still looks as if the good fgen band (with 2-4 inch per hour
snowfall rates) should stay north and west of the I-84 corridor.
Short term /Tuesday through Tuesday night/...
a major Nor'easter to impact region...bringing a blizzard with up to
two feet of snow in Litchfield County. Heavy snow with some blowing
and drifting snow will impact the Hudson Valley from the Saratoga
region southward...with more than a foot of snow to fall south of
Albany...8-12 inches Albany northward.
The Winter Storm Watch for the Mohawk Valley (including all of
Fulton county) as well as northern Warren County was converted into
an advisory. The remainder of the headlines for winter storm
warnings (and the blizzard in Litchfield county) remain the same.
All times remain the same starting at 100 PM and ending by midnight
By tonight...high pressure will drift offshore...allowing the flow
to become more northeasterly which will allow for an increase in
At the same time...surface low pressure will begin to reform off the
coast of Cape Hatteras by late in the day. The low will interact
with a strong baroclinic zone offshore...and a strong piece of middle
level energy (already evident on the water vapor loop) working to
the east of the southern Appalachian Mountains.
As a result...strong isentropic lift will generate moderate to heavy
snowfall to the north and west of the storm as frontogenesis
increases markedly. This snow will rapidly fill in to the south and
east of the capital region early this evening...then overspread
most of the remainder of our region by the overnight.
The 00z model guidance has overall trended a tad further east with
the track of the low pressure...placing it about 50 miles to the
east of Montauk Point on Long Island by Tuesday morning. At this
point...the upper level portion of the storm will have "captured"
the surface storm...peaking its intensity as it will likely fall
below 980 mbs and produce quite a gradient over areas from the coast
to about 100 miles inland.
This will produce strong northeast wind even in our southeastern
zones (litchfield) strong enough to justify a Blizzard Warning
(already issued) with gusts to 40 miles per hour. This wind combined with a
fairly dry snow will produce extensive blowing and drifting of snow
and life threatening conditions.
Further inland...terrain damping will produce much less wind in the
Hudson Valley...but even here...with the snow being dry and
powdery...wind gusts of 25 miles per hour could produce a little blowing and
drifting snow in the outlying areas. Higher terrain areas like the
Catskills...Berkshires and southern greens will see a little more
blowing and drifting snow...but the wind at this point looks to just
fall below blizzard criteria.
There is likely going to be a sharp line of demarcation between
heavy snow...and light to moderate snowfall (determined by where
exactly the f-general sets up). Most 00z model guidance points to this
areas being close to...or just to the northwest of the I-84
corridor...including Litchfield County and southeastern Dutchess
County. This where snowfall rates late tonight into early Tuesday
could reach 3-4 inches per hour...perhaps even a rumble of thunder.
For now...decided not include any thunder since the best chance of
this happening might be closer to the coast. This band could set for
several hours...producing prolific amounts of snowfall.
Further north and west into the Hudson Valley and
Catskills...smaller bands or bandlets could produce snowfall rates
of 1-2 inches per hour...probably not lasting as long as the
classical frontogentic band...mainly on Tuesday.
Outside of these bands...snowfall rates in the Mohawk Valley
northwestward will generally peak in the one half inch to one inch
per hour...often falling lightly. Still...even in these
areas...light snow could fall for a long duration producing a
respectable 4 to 8 inches of snow in a twenty four hour
Snow to liquid ratio should be high...around 15:1 in most areas. The
good news...this will not be the type of snow to bring down power
lines. However...the wind themselves might be enough for a local
power outage or two in Litchfield County. However...the fluffier is
more prone to blowing and drifting.
Overnight lows and highs on Tuesday will very cold...single numbers
north and teens north. The cold...combined with the wind...mainly in
Litchfield County will again lead to very dangerous travel
conditions. Travel is strong discouraged. Highs on Tuesday will be
20-25 Albany south...teens north.
By Tuesday night...low pressure will begin to weaken and loose it
deep moisture. Snow will slowly diminish in intensity...but not
ending until late Tuesday night or early Wednesday. There will still
be some wind adding a little more blowing and drifting of the snow.
Roads will likely not improve until Wednesday.
By Wednesday...the low will depart into the Gulf of Maine...taking
any remaining nuisance snow with it. Increasing sunshine will be the
rule...but it will remain cold and breezy. Highs will be in the
20s...except teens Adirondacks and southern greens.
A steep snowfall gradient with this storm will be across our
forecast area. A graphic of our forecast total snowfall is available
on our web Page under news headlines.
Long term /Wednesday through Sunday/...
active long term period expected with increasing potential for
another storm system to produce accumulating snowfall across the
region Thursday into Friday.
A rather tranquil period of weather expected Wednesday night into
early Thursday as surface ridge and positive height rises are
expected along the eastern Continental U.S. In the wake of the East Coast
storm. So a mostly clear sky will eventually filter with more
clouds overnight into early Thursday as temperatures will be near to
slightly below normal for the end of January.
The next clipper system is still forecast to arrive later Thursday
and could have lasting impacts into Friday. Unlike the current East
Coast storm...this wave will be predominately northern stream.
However...one can not ignore a few of the ensemble members with yet
another amplification along the Gulf Stream which leads toward a
more negatively tilted trough axis Thursday night which would allow
for lasting impacts into Friday. For now...we will follow the
previous excellent set of the grids/forecast with high chance probability of precipitation
and continue to highlight in the severe weather potential statement.
The weekend appears to be turning colder with some discrepancy if
another pv anomaly impacts our region as suggested by the GFS.
Either way...a much colder air mass seems to be in the picture as
the qbo returns /quasi-biennial oscillation/ as the eastern higher
latitudes exhibit a strong blocking pattern.
Aviation /18z Monday through Saturday/...
major Nor'easter will have a severe impact on all terminals mainly
tonight and Tuesday with snow and some wind.
Mainly VFR conditions will continue at kgfl/kalb well into this
evening...while kpou/kpsf have occasional IFR conditions in light
snow well out ahead of the developing low off the middle Atlantic
coast. As the low moves northeast and then northward for a time
tonight and early Tuesday. Snow will become steadier and heavier
tonight with widespread IFR to LIFR conditions spreading slowly
northward across the taf sites. At kpou widespread IFR or less
conditions will begin around or after 27/01z...03z at kpsf...05z at
kalb...and 08z at kgfl. During the daylight hours on Tuesday...
mainly vlifr conditions expected at all the taf sites in moderate to
heavy snow and some blowing snow.
Surface will be mainly northerly at 8 to 10 kts for the rest of
today...then 8 to 12 kts tonight with some gusts to 15 to 20 kts at
kpsf/kpou. On Tuesday winds will continue from the north to
northwest at 12 to 14 kts with gusts of 15 to 25 kts.
Tuesday afternoon: major operational impact.Breezy definite snow.
Tuesday night: moderate operational impact. Chance of snow.
Wednesday: no operational impact. No sig weather.
Wednesday night: no operational impact. No sig weather.
Thursday: moderate operational impact. Chance of snow.
Thursday night: moderate operational impact. Chance of snow.
Friday: moderate operational impact. Chance of shsn.
no significant Hydro problems are expected through the middle of the
week. The precipitation that does occur will be in the form of snow.
A significant snowfall will occur tonight and Tuesday across western
New England and most of east central New York.
Ice will continue to thicken on rivers...streams...creeks...lakes
and other bodies of water.
The Eagle bridge gage on the hoosic river continues to be hampered
by ice effects.
For details on specific area rivers and lakes...including observed
and forecast river stages and lake elevations...please visit the
advanced hydrologic prediction service /ahps/ graphs on our website.
CT...Blizzard Warning until 1 am EST Wednesday for ctz001-013.
New York...Winter Storm Warning until 1 am EST Wednesday for nyz041-043-
Winter Weather Advisory until 1 am EST Wednesday for nyz039-
Massachusetts...Winter Storm Warning until 1 am EST Wednesday for maz001-025.
Vermont...Winter Storm Warning until 1 am EST Wednesday for vtz013>015.