Area Forecast Discussion
Issued by NWS Albany, NY

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245
FXUS61 KALY 191440
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
940 AM EST Sun Nov 19 2017

.SYNOPSIS...
A strong cold front will sweep across the area this morning. Conditions
will become blustery with a colder air mass being ushered in during
the day. Precipitation will become less widespread with a mix and
changeover to snow across the the higher terrain. Lake effect snow
will develop by this evening impacting the western and central Mohawk
Valley and Schoharie Valley tonight then shifting northward into
the western and southern Adirondacks on Monday. While isolated
to scattered showers are expected elsewhere.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 940 am est...Strong surface low is lifting across
northern Vermont and surface cold front extends southward across
our portion of western New England. In the wake of the front,
strong westerly winds are developing, with gusts of 40-55 mph
occurring across much of the Mohawk Valley and Capital Region.
Albany Airport gusted to 49 kts (56 mph) last hour right behind
the frontal passage. Winds will be picking up across southern VT
and the Berkshires shortly, and we have expanded the Wind
Advisory to now include all of southern Vermont.

Although temps were in the mid 40s to low 50s ahead of the
front, temps are rapidly falling into the 30s behind the
boundary. Temps will continue to hold steady or slowly fall this
afternoon.

Web cam imagery already shows lingering light precip has
changed over to snow across the western Adirondacks with a light
coating in the Old Forge area. Up to an inch or so is possible
there, as light upslope snowfall continues through the day.
Another spot which could see an inch or two of accumulation
today is the southern Green Mountains with moist upslope flow,
as temps quick cool later this morning behind the boundary. Some
light rain or snow showers are also starting to develop within
the upslope flow across the Taconics as well, and a light
coating of snow is possible there by later today as well.
Elsewhere, the coverage of showers should diminish today, but
cannot rule out some light passing sprinkles or flurries,
especially for western facing slopes.

Tonight, concern turns toward lake effect snow potential. H850 temps
fall to near -12C over Lake Ontario, representing a Delta-T of
around 22C. A secondary shortwave, seen crossing the Upper Midwest
early this morning, will result in a return to cyclonic flow tonight
after very brief midlevel ridging this afternoon. Per local
research, good setup for inland extent of LES band, given multi-lake
(Superior/Georgian Bay) connection, moderate instability, fairly
unidirectional low-level flow, good speed shear in the sfc-1 km
layer, low speed shear in the 1-3 km layer, and inversion depths
approaching 3 km agl per forecast soundings at KUCA. The band looks
to target southern parts of the Mohawk Valley into the Schoharie
Valley initially (around 00-03Z). Thereafter, the band has the
potential to extend eastward toward the Capital District, Taconics,
Berkshires, and possibly even NW CT. Roughly 1 to 4 inches is
forecast overnight where the band will be the most long-lived
(Mohawk/Schoharie Valleys), with a few tenths up to an inch over the
remainder of the aforementioned areas depending on where exactly the
band sets up. Since it is lake effect, there is potential for sharp
snowfall gradients and isolated higher totals if the band remains
stationary. Hi-res models show potential for large inland extent,
e.g., the 4km NAM extending a snow band clear into northeastern CT.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
Lake effect snows will continue on Monday. However the low level
flow will back as ridging builds in and the band will shift northward
out of the Schoharie and western/central Mohawk Valleys into the
western and southern Adirondacks. An additional inch or so of snow
is expected Monday in the western Mohawk Valley with 1 to 3 inches
in the western Adirondacks. Isolated to scattered snow showers
are expected across much of the forecast area during the day
with upslope snow showers across the Taconics, Berkshires and
southern Green Mountains with the brisk westerly flow.

It will be another blustery day as the region is squeezed between
the departing system and an advancing highs. Will have westerly
flow again however not be as strong as today (Sunday). Expecting
gusts up to 30 to 35 mph down the Mohawk Valley across the Capital
District, Taconics and Berkshires as well as across the eastern
Catskills, Litchfield Hills and southern Green Mountains.

Temperatures will run 5 to 10 degrees below normal mainly in the
30s. Lower 40s are forecast for the mid Hudson Valley with
mid/upper 20s for the terrain 2000 feet and above.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Fair conditions are expected much of the week with unsettled weather
for the weekend. Guidance is in general agreement the longwave should
feature a trough over the Great Lakes region and Northeast with
northern stream short waves reinforcing it. While southern stream
energy should remain separated.

A cold front is expected to sweep across the region Tuesday night
into Wednesday however the main low passes well to our north
across eastern Canada and moisture should limited. A coastal low
associated with southern stream energy is forecast to pass well
south of Long Island during the day Wednesday. Only have slight
to low chance pops across local area for snow and rain showers.

Surface high builds in and is expected to dominate our weather
through Friday while aloft the region is expected to between
short wave troughs. Thus fair weather with light winds expected
Thanksgiving.

The next northern stream short wave is expected to deepen the
trough across the eastern United States with its associated low
pressure system forecast to track across the Great Lakes into
the Northeast Saturday. There are some differences in the guidance
with the exact track and timing of the system however there is
agreement the main low should pass to our north; the question
is how far to the north. Introduced pops Friday night as system
approaches with chance pops across the area with snow showers
changing to rain showers as we warm in southerly flow ahead of
the system.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
Strong cold front continues to move across the region. Winds are
shifting to the west with a strong gusts with its passage. This
is expected to occur around 13Z for KALB/KPOU/KGFL and around
14Z for KPSF. MVFR conditions are expected to improve to VFR in
the wake of the frontal passage, although upsloping should keep
ceilings at MVFR levels much of the TAF. Chances for showers
will decrease as the day progresses at the TAFs sites with
chances for snow showers returning at KALB and KPSF this evening
as lake effect develops. Have addressed threat with VCSH in
TAFs at this time.

Southerly winds ahead of the cold front will wipe around to the west
with its passage, The westerly winds will be strong and gusty
today with sustained winds of 20 to 30 knots and gusts 35 to 40
knots. Winds will decrease early this evening but remain gusty.
The gusts are expected to die off at KPOU and KGFL however
persist through the overnight at KALB and KPSF.

Outlook...

Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: Low Operational Impact. Slight Chance of SHRA...SHSN.
Wednesday: Low Operational Impact. Slight Chance of SHRA...SHSN.
Wednesday Night: No Operational Impact. NO SIG WX.
Thanksgiving Day: No Operational Impact. NO SIG WX.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.

&&

.FIRE WEATHER...
A strong cold front will sweep across the area this morning.
Conditions will become blustery with a colder air mass being
ushered in during the day. Precipitation will become less
widespread with a mix and changeover to snow across the the
higher terrain. Lake effect snow will develop by this evening
impacting the western and central Mohawk Valley and Schoharie
Valley tonight then shifting northward into the western and
southern Adirondacks on Monday. While isolated to scattered
showers are expected elsewhere.

&&

.HYDROLOGY...
No hydrologic problems are expected on the main stem rivers for
the next several days.

A strong cold front will sweep across the area this morning
and precipitation will become less widespread with a mix and
changeover to snow across the the higher terrain as colder air
is ushered in. Lake effect snow will develop by this evening
impacting the western and central Mohawk Valley and Schoharie
Valley tonight then shifting northward into the western and
southern Adirondacks on Monday. While isolated to scattered
showers are expected elsewhere. Mainly fair weather is then
expected the rest of the week with unsettled weather expected
for next weekend.

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.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory until 6 PM EST this evening for CTZ001-013.
NY...Wind Advisory until 6 PM EST this evening for NYZ038>040-
     047>054-058>061-063>066-082.
MA...Wind Advisory until 6 PM EST this evening for MAZ001-025.
VT...Wind Advisory until 6 PM EST this evening for VTZ013>015.

&&

$$
SYNOPSIS...IAA
NEAR TERM...Frugis/Thompson
SHORT TERM...IAA
LONG TERM...IAA
AVIATION...IAA/Thompson
FIRE WEATHER...IAA
HYDROLOGY...IAA



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