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Area forecast discussion 
National Weather Service Albany New York
656 PM EST sun Feb 1 2015

Synopsis...
a low pressure system passing to our south will bring a widespread
significant snowfall to the area tonight through Monday. The snow
is expected to become heavy before sunrise then continue through
the day...coming down heavy at times in the morning. The steady
snow is expected to taper off to scattered snow showers by
evening. Another shot of Arctic air will be ushered into the
region Monday night into Tuesday.

&&

Near term /through Monday/...
winter storm warnings remain in effect for entire forecast area
for a widespread significant snowfall tonight and Monday. High
confidence forecast.

As of 655 PM EST...regional mosaic radar shows snowfall still well
upstream of the region over western NY/PA. The latest 3km hrrr
shows steady light snowfall beginning across our area between 02z-
6z going from southwest to northeast. The upper level dynamics are
still way back to the west across the Midwest...but its headed
towards our area.

Overrunning snowfall will occur across the region tonight and Monday
as a low pressure system passes to our south. Have a vigorous
northern stream system combining with southern stream moisture. The
guidance remains in agreement keeping the system progressive with
an open wave aloft. However the guidance has trended a bit farther
to the north with the track of the storm. The low is now expected to
move across Pennsylvania and New Jersey then across New York City
and Long Island. This storm track allows warmer air to penetrate
farther inland which should result some sleet into the middle Hudson
Valley and northwestern Connecticut for a brief time Monday morning.

The ensemble plumes guidance remain well clustered which increases
confidence in our snowfall forecast. Also the probabilistic
guidance indicates 80+% chances for 8+ inches of snow across the
forecast area.

Snow ratios across the southern portion of the forecast are still
expected to start out high then trended toward climatology...while
ratios will remain high across much of the forecast area especially
as you head northward.

Guidance indicates the snow will increase in intensify before
sunrise and come down heavy at times through the morning. This is
when the best isentropic lift will occur as the strong 60-70 knots
low level jet passes to our south with 40-50 knots winds north of
the frontal boundary across the local area. Snowfall rates of 1 to 2
inches an hour can be expected.

The snow is expected to taper off by evening so keeping the 6 PM
expiration time. There could be some light snow after 6 PM.

&&

Short term /Monday night through Tuesday night/...
in the wake of this storm another shot of Arctic air. This along
with a fresh snow cover...temperatures Monday night are anticipated
to drop into the single digits in the middle Hudson Valley with 10
degrees below zero and colder across the southern Adirondacks.
Will likely need wind chill warning and advisories for Monday
night into Tuesday morning...have highlighted in our hazardous
weather outlook.

Brisk and gusty northwesterly winds Monday evening will cause
blowing and drifting of the snow. The winds will slacken overnight
as the low moves farther away and ridging builds in.

Higher pressure will build in and quickly shift across the area
Tuesday as a clipper system approaches from the northwest with chances
for snow showers into the western portion of the forecast area
late Tuesday night.

Tuesday will be another cold day with highs mainly in the
teens...15 to 20 degrees below normal. Temperatures Tuesday night
will be much warmer than Monday with a southerly flow across the
area ahead of the clipper...but still below normal by 5 to 10
degrees.

&&

Long term /Wednesday through Sunday/...
the extended forecast period features below normal temperatures with
a couple of Arctic fronts impacting eastern New York and western New England
Wednesday-Wednesday night...and another on the weekend.

The long term opens with fairly good agreement with the ensembles
and medium range operational guidance that a clipper low will move
across PA/New York with an amplifying positively tilted h500 longwave
trough. There is a good chance of snow showers with perhaps a period
of upslope snowfall for the western dacks...and southern greens late Wednesday PM
into the evening. Snowfall accums look light with an inch or less in
most locations with 1 to 3 inches in the western/southern dacks...and southern
greens. Some warm advection will occur ahead of this system with
highs warming closer to normal in the middle and u20s from the capital
district...Mohawk Valley...and the Berkshire north and west...and
u20s to l30s to the south and east. The Arctic front slides through
the region Wednesday night...and much colder air moves back into the forecast
area with lows in the teens from the capital district south and
east...and single digits to slightly below zero north and west.

Thursday-Thursday night...bitterly cold air moves back into eastern New York and western New
England in the wake of the front. Some residual scattered flurries and
isolated snow showers will linger during the day with maximum temperatures in the
teens to l20s with the southern dacks struggling to get out of the single
digits. H850 temperatures tumble close to -20c to -25c over the forecast area
with blustery northwest winds. Lows temperatures will be bitterly cold in the 10
to 20 below zero range north and west of the capital region and zero
to almost 10 below south and east with winds of 5 to 15 miles per hour will
yield some dangerous wind chills in the 15 to 30 below zero range.
Wind chill headlines will likely be needed again.

Friday-Friday night...Arctic high pressure builds in from the Midwest and
Ohio Valley with a cold finish to the week. Sunny skies will give
way to increasing clouds at night with another short-wave
approaching from the Canadian prairies and the Great Lakes region.
This disturbance will bring another shot of Arctic air for the
weekend. The threat for some isolated snow showers increases with
the warm advection ahead of the clipper. After highs only in the
teens...lows will be in the -5f to +5f range.

Saturday into Sunday...Arctic front rockets through the region on
Saturday based on the GFS/ECMWF/wpc guidance with isolated-scattered snow
showers and squalls. Highs in the 20s on Saturday will be
brief-lived. Lows will be back in the single digits and below
zero. Some wind chills may get close to advisory levels once
again...especially over the higher terrain. Arctic high will build
in for Sunday with cold and dry weather to close the week.

Bottom line...below normal temperatures are here to stay for awhile in the
northeast.

&&

Aviation /00z Monday through Friday/...
overcast middle level clouds are currently in place with VFR conditions.
However...steady light snowfall will be arriving between 02z-05z
over the area and ceilings lowering to about 4 kft. Flying conditions
may drop to MVFR for an hour or two initially...but will then go
IFR with snow around 2sm. By late tonight...snow will increase in
intensity...and moderate snow with 1/2sm looks likely for all
sites. This will continue through the morning hours with LIFR
conditions for all sites. Snow may start to lighten up for the
afternoon hours...but will continue to be IFR. Snow may finally taper
off to snow showers by the late afternoon or early evening hours on
Monday...with flying conditions returning to MVFR for both
cigs/vsby.

Precipitation type should be nearly snow. A brief period of pl mixing in
with the snow is possible during the morning hours on Monday at
kpou...but not enough confidence in this occurring to include in
the taf at this time.

Winds will generally be north-NE at 5-10 kts during much of the storm.
As the storm start to wind down...winds may become north-northwest...but will
increase to about 10-15 kts...especially for kalb/kpsf.

Outlook...

Monday night: moderate operational impact. Chance of snow in the evening.
Tue: no operational impact. No sig weather.
Tuesday night: low operational impact. Slight chance of shsn.
Wednesday-Wednesday night: moderate operational impact. Chance of shsn.
Thu: low operational impact. Breezy. Slight chance of shsn.
Thursday night-Fri: no operational impact. No sig weather.

&&

Hydrology...
no significant Hydro problems are expected this week. Widespread
significant snowfall tonight through Monday. Continued cold with
below normal temperatures which will allow ice to thicken on
rivers...streams...creeks...lakes and other bodies of water.

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.

&&

Climate...
Albany season snowfall total January stands at 40 inches which is
5.9 inches above normal.

The top 10 greatest February snowstorm for Albany...
23.5 inches...February 14, 1914
18.2 inches...February 22-25, 1893
17.9 inches...February 15-16, 1958
17.1 inches...February 24-25, 1966
16.8 inches...February 13-14, 2007
16.7 inches...February 6-8, 1983
15.5 inches...February 4, 1926
15.0 inches...February 1, 1898
14.7 inches...February 19-20, 1946
14.6 inches...February 13-16, 1950

&&

Aly watches/warnings/advisories...
CT...Winter Storm Warning until 6 PM EST Monday for ctz001-013.
New York...Winter Storm Warning until 6 PM EST Monday for nyz038>041-
047>054-058>061-063>066-082>084.
Winter Storm Warning from midnight tonight to 6 PM EST Monday
for nyz032-033-042-043.
Massachusetts...Winter Storm Warning until 6 PM EST Monday for maz001-025.
Vermont...Winter Storm Warning until 6 PM EST Monday for vtz013>015.

&&

$$
Synopsis...iaa
near term...iaa/frugis
short term...iaa
long term...wasula
aviation...frugis
hydrology...iaa
climate...

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