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Area forecast discussion 
National Weather Service Albany New York
933 am EST Friday Jan 30 2015

Synopsis...
low pressure will move to our east of Cape Cod this afternoon.
An Arctic front will cross the region this afternoon. Periods of
snow this morning followed by scattered to numerous snow showers
and perhaps a snow squall this afternoon. A bitterly cold Arctic
air mass will follow ushered in by strong gusty winds which will
produce dangerously cold wind chills tonight into Saturday
morning.

&&

Near term /until 6 PM this evening/...
as of 930 am EST...snow has become moderate to heavy at times
across a large portion of the forecast area including the capital
region...northern Catskills...N-cntrl Taconics...and southern Vermont as the
strong differential vorticity advection from the short-wave trough
coupled with low-level convergence evident in the Mohawk/Hudson
River valley and a saturated column are focusing the snow.

An additional 1 to 3 inches is possible...and the advisory will
remain up to the north...and we will extend it to 1 PM in terms of
the snowfall. We will use Special Weather Statement statements outside the
advisory...instead of flip flopping back and forth on the headlines.

This is not a classic clipper...since a secondary low has formed
just south and east of Long Island /more of a hybrid system/. Expect a 2
to 6 snowfall across most of the region...with isolated higher
amounts...and isolated lower amounts.

Highs temperatures will be close to current readings in the 20s to l30s.
An Arctic front will swing through this afternoon.

There will be scattered snow showers around and perhaps even an
isolated snow squall this afternoon. However the big story will be
strong gusty winds reaching 35-40 miles per hour most places which will begin
to drive temperatures downward. After cresting midday...they will
drop back through the 20s during the afternoon/teens Adirondacks.

&&

Short term /6 PM this evening through Saturday night/...
wind chill warnings for northern Herkimer County and Hamilton
counties. Wind chill advisories for the remainder of eastern New
York and adjacent New England. All times are from 6 PM through 11am
Saturday.

Tonight...there still could some upslope snow showers for awhile
across the southern greens of Vermont. Otherwise...the sky should
eventually clear but the wind will continue and temperatures will
dive to near zero in the capital region...5 to 15 below zero across
our northern zones...single numbers south of the capital region.
Wind gusts will again be in the 35-40 miles per hour range at times.

The combination of the wind and very cold temperatures has prompted
US to continue wind chill advisories everywhere tonight except wind
chill warnings northern Herkimer and Hamilton counties.

The wind will be result of a deep low pressure deepening in the Gulf
of Maine. The low will only slow further move away on Saturday.

Saturday will be a mainly sunny but windy and bitterly cold day. The
wind will abate a little during the afternoon...but temperatures
only recover to 20 at best in the middle Hudson Valley...teens further
north in and around the capital region...only single numbers over
our northern areas...including most of southern Vermont.

Saturday night...believe it or not...yet another Arctic front a weak
clipper will work across New York state. Any sensible weather should
be mainly confined to areas north of the capital region where clouds
and the threat of snow showers will exit. The approaching front
will serve to prevent temperatures from falling quite as low as they
would have otherwise. Still look for temperatures around zero to
then north of the capital region...single numbers to around 10
capital region and points south.

&&

Long term /Sunday through Thursday/...
nearly excellent synoptic agreement among the long term forecast
guidance this morning as the forecast trends for the Monday event
have trended northward once again.

For Sunday...February 1st...Arctic frontal boundary that we have
been discussing the past several days is still prognosticated to slide
southward and either stall or become ill-defined through the day.
Placement of this front does differ among the guidance with recent
tendencies placing it along or just north of the i80 corridor. Then
we quickly shift our attention to the approaching Ohio Valley system.

The strong pv anomaly was ashore along British Columbia as
moisture continues to advect into The Four Corners region per the
water vapor analysis this Friday morning. The combination of these
features are forecast to merge across the Central Plains/mid-
Mississippi River valley Sunday night and spawn surface
cyclogenesis between i70-i80. The upper trough amplifies over the
Ohio Valley as the surface low begins to deepen across the middle
Atlantic Monday morning. The quantitative precipitation forecast fields and 2d-fgen fields line up
mainly south of i90 on Monday where an accumulating snow event is
expected. Ensemble data and plumes now suggest more than half the
members are further north than previous runs. In fact...the latest
30/06z nam12 is further north as well with moderate quantitative precipitation forecast values. We
will reintroduce this potential Miller type b event into the severe weather potential statement
at this time. Thermal profiles across the region are not only cold
but will offer a challenge with respect to liquid to snow ratios.
The higher ratios will likely be along and north of i90 where
values could be approaching 20:1. Still plenty of time as this pv
anomaly will be entering the upper air network which
should...hopefully...resolve and narrow the solutions. As an
for your information...evaluating the latest cips guidance...many of the matches do
bring an accumulating snow to the region.

This wave departs off the coast Monday evening as 1030mb surface
high slides into the Ohio Valley and extends its influence into the
northeast. As h850 temperatures are expected to fall below -20c...and
potential for a fresh snow cover...will provide the opportunity for
a very cold night across the region. Would not be surprised if some
locations attempt to approach record lows.

The high slides across the middle Atlantic region through Tuesday which
should keep our weather pattern tranquil yet chilly. Next Arctic
impulse is forecast to move southeast toward the Great Lakes region
for the middle week period with another chance for snow showers later
Wednesday into Thursday. The timing of this Arctic frontal and
track of a southern stream impulse could make for an interesting
coastal development through Thursday. While majority of the
ensemble members keep this wave offshore...there are a few outlying
members that keep this wave closer to the coastline.

Temperatures through the period will be below normal.

&&

Aviation /14z Friday through Tuesday/...
periods/occasional bursts of snow will continue to move across the
region this morning. Due to this...visibilities will be a challenge
to forecast as we will observe MVFR to IFR in short/brief bursts.
At the minimum...ceilings will be solidly in MVFR at all taf sites
through at least this morning.

Trends in the short term models continue to hint at band of snow
moving through the Hudson River valley this morning where the best
potential for IFR conditions at all taf locations.

Thereafter...during the late morning hours...conditions will improve
with respect to diminishing trends in the snow and low ceilings. Then a
wind shift will result in an increase of magnitudes where some
blowing snow could result for the remainder of the day.

Winds this morning will generally be southerly around 10kts with
some gusts. Winds will quickly shifts to the west then northwest
around noon with 10-15kts with gusts at or above 20kts.

Outlook...

Saturday night: low operational impact. Slight chance of shsn.
Sunday: no operational impact. No sig weather.
Sunday night: moderate operational impact. Chance of snow.
Monday: moderate operational impact. Chance of snow.
Monday night: no operational impact. No sig weather.
Tuesday: no operational impact. No sig weather.
Tuesday night: no operational impact. No sig weather.
Wednesday: low operational impact. Slight chance of shsn.

&&

Hydrology...
no significant Hydro problems are expected through the next 5 days.

Snow will taper to snow showers by afternoon. Snowfall will range
from 1-3 inches from the capital region southward...3-6 inches
further north.

Additional snow showers are possible this afternoon into evening
with generally minor additional accumulations.

There is also a low to moderate chance of snow Sunday night into
Monday.

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.

&&

Aly watches/warnings/advisories...
CT...Wind Chill Advisory from 6 PM this evening to 11 am EST
Saturday for ctz001-013.
New York...Wind Chill Advisory from 6 PM this evening to 11 am EST
Saturday for nyz038>043-047>054-058>061-063>066-082>084.
Winter Weather Advisory until 1 PM EST this morning for
nyz032-033-038>043-082>084. Wind chill warning from 6 PM this
evening to 11 am EST Saturday for nyz032-033.
Massachusetts...Wind Chill Advisory from 6 PM this evening to 11 am EST
Saturday for maz001-025.
Vermont...Wind Chill Advisory from 6 PM this
evening to 11 am EST Saturday for vtz013>015. Winter Weather
Advisory until 1 PM EST this morning for vtz013>015.

&&

$$
Synopsis...hwjiv/wasula
near term...hwjiv/wasula
short term...hwjiv
long term...bgm
aviation...bgm
hydrology...hwjiv/wasula

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