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Area forecast discussion 
National Weather Service Albany New York
1244 PM EST sun Jan 25 2015

Synopsis...
an Arctic air mass will move across our region today allowing for
much colder temperatures. A significant coastal storm will impact
the region Monday afternoon through Tuesday.

&&

Near term /until 6 PM this evening/...
no changes to current headlines at this time. Significant
Nor'easter to impact region Monday afternoon through Tuesday.

Cold front has cleared the forecast area. Brisk and gusty winds
will decrease as ridging builds in from northwest as we head
through the afternoon. Temperatures will continue to fall despite
the sunshine.

&&

Short term /6 PM this evening through 6 PM Monday/...
a large ridge of high pressure centered over southern Canada will
nose into our region tonight. It will be cold and fair tonight
with lows forecast to range from 10 below zero northwest to around
10 above zero southeast.

On Monday a storm system will move to the middle Atlantic coast
and the track northeastward toward southern New England coast.
This will result in increasing clouds during the morning hours
with snow developing from southwest to northeast across the area
during the afternoon. There is good frontogenetic forcing with
this system and banding of snow is expected especially starting
late Monday. We have some light accumulating snows as far north as
the Mohawk Valley and Lake George Saratoga region for Monday
afternoon. Snowfall totals through Monday afternoon should
generally range from a few tenths of an inch north to around an
inch or so south. Expect highs on Monday to be in the range from
the middle teens northwest to the middle 20s southeast.

&&

Long term /Monday night through Saturday/...
Winter Storm Watch for most of eastern New York and western New England
for Monday afternoon through Tuesday night...

Monday nt-Tuesday nt...the potential for significant impacts from a major
coastal storm continues to increase...especially across western New
England. 00z/25 deterministic models and ensemble suites continue to
support the idea that a clipper type system explosively intensifies
off the northern middle Atlantic coast Monday...and slows its forward
movement as strong upper level energy impinges from the
northwest...allowing for a closed middle/upper level low to form and
capture the intensifying low...and thereby allowing it to possibly
retrograde/loop for a bit southeast of Long Island before tracking
northeastward. The key to this overall evolution appears to be in
part related to a secondary pv anomaly racing east across western
Canada today before diving southeast into south central Canada
tonight and Monday. This pv anomaly helps to induce the closed low
that eventually captures the developing surface low...preventing it from
moving out to sea. There remains some uncertainty in how this
evolves...including how far north and west the surface low potentially
retrogrades as it is captured by the upper level feature. The
00z/NAM and UKMET appear to be outliers at this time with less
capturing and a more progressive evolution...although can not be
completely discarded.

Based on the available guidance...it appears that snow should
develop across southwest areas by Monday afternoon...in association
with isentropic lift. Then...as the surface low rapidly strengthens and
pivots north and west...strong middle level f-general is expected to allow for
bands of snow to move northwest or west across the region late Monday
nt into Tuesday. How far west these bands reach remains in
question...but confidence is high enough at this time for a watch
issuance...with the best chance for heavy snow across western New
England. Should the storm evolve as some of the westernmost guidance
suggest...then widespread heavy snow and strong winds could
eventually encompass much of eastern New York outside of the western
Mohawk Valley and Adirondacks on Tuesday.

Additional refinements will be made to the forecast as newer
guidance becomes available.

Wednesday-Wednesday nt...in the wake of the potential winter storm...high
pressure should translate east across the region...with a break in
precipitation. Temperatures will remain below normal.

Thu-Fri...there is a possibility of another storm system to affect
the region during this time frame...although details are very
sketchy. At the very least...a period of steady snow or snow showers
should move across the region during this time frame. Temperatures will
remain below normal.

Sat...below to well below normal temperatures are expected. Some lingering
snow or snow showers could affect eastern portions of the region.

&&

Aviation /18z Sunday through Friday/...
as we start the taf period...weather conditions will remain tranquil
as a storm system will move toward the region affecting most taf
sites toward the end of the taf period. As we start the taf period
up through 06z Monday...all taf sites will experience VFR conditions
with just some high clouds moving into the region. As we go past 09z
Monday... areas in our southern region around kpou will experience
some light snow moving into the region ahead of the main low
pressure system with lower ceilings. It wont be until after 12z
Monday where kalb/kpsf/kpou will experience more wide range snow
where MVFR/IFR conditions are expected in conjunction with low ceilings
and visbys.

Winds will be out of the northwest before 00z Monday shifting to the
north and then northeast as the storm impacts parts of the region.
Winds will generally be between 5 to 10 knots.

Outlook...

Monday night-tuesday: high operational impact. Definite snow
Tuesday night: moderate operational impact. Chance of snow.
Wednesday-Wednesday night: no operational impact. No sig weather.
Thursday-friday: moderate operational impact. Chance of snow.

&&

Hydrology...
no significant Hydro problems are expected through the middle of
the week. The precipitation that does occur will be in the form
of snow...some of which may east heavy Monday night through Tuesday
evening.

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...Winter Storm Watch from Monday afternoon through late Tuesday
night for ctz001-013.
New York...Winter Storm Watch from Monday afternoon through late Tuesday
night for nyz041>043-047>054-058>061-063>066-083-084.
Massachusetts...Winter Storm Watch from Monday afternoon through late Tuesday
night for maz001-025.
Vermont...Winter Storm Watch from Monday afternoon through late Tuesday
night for vtz013>015.

&&

$$
Synopsis...iaa/frugis/11
near term...iaa/11/NAS
short term...11
long term...kl
aviation...lfm
hydrology...iaa/11

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