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Area forecast discussion 
National Weather Service New York New York
432 PM EST Monday Jan 26 2015

Synopsis...
a powerful noreaster will impact the region through Tuesday. High
pressure builds in for Wednesday...moves overhead Wednesday night
and offshore on Thursday. Meanwhile...low pressure over the
central US tracks through the Great Lakes Thursday and across New
England on Friday. High pressure builds back for the weekend and
then another storm system could impact the area early next week.

&&

Near term /until 6 am Tuesday morning/...
997 low about 200 miles east of the Delaware-Maryland-Virginia at 4 PM per msas. Water
vapor shows an extensive subtropical tap from the Pacific to the
western Atlantic. The radar composite indicated banding over Li...with
developing precipitation S of Li flowing northward.

The end result is that conditions will continue to deteriorate through
the early evening across the entire County Warning Area.

Snowfall rates will pick up from around 1 inch per hour into the 2-4
inch per hour range by 10pm or so. Some locally higher rates possible
with convection.

The favored NAM and European model (ecmwf) solutions drop the low into the 970s
overnight. As this occurs...the winds will rapidly increase with
gusts in excess of 40-50 miles per hour. Across extreme eastern Li...wind gusts
up to 70 miles per hour possible. Based this on the NAM...it is possible that
some even locally higher gusts are possible at the peak of the
storm.

Significant blowing and drifting of snow after midnight...with
whiteout conditions.

&&

Short term /6 am Tuesday morning through Tuesday night/...
it should be a raging blizzard at 6am...with heavy snow...damaging
winds and whiteout conditions across most of the area. Extreme
northwestern zones such as Orange and western Passaic may be a bit marginal
with respect to winds.

The low essentially stalls somewhere S of Cape Cod during the
day...then drifts away to the NE Tuesday night bringing and end to the
storm.

Depending on exactly where the storm sets up...there is the
potential that the dry slot could work into the region from the
north...cutting off the heavier precipitation where this occurs. West of this area
will be where the best deformation zone will be. The models differ
on this...with the 18z NAM placing this band over the city.

The snowfall forecast remains in the 20-30 inch range with locally
higher amts. A little less forecast across northwestern zones...but the latest
NAM suggests even over 2 feet into Orange County. The model produces
2.7 inch liquid over the Bronx...so there is definite 3 feet
potential with this system. Where exactly that ultimately plays out
remains to be seen.

With respect to temperatures...the guidance seems to be picking up the passage of a
coastal front on Li. For example...the met brings temperatures up to 41
degrees at kfok tonight. This seems unrealistic at this time with sustained
30kt northerly winds in the same guidance. As a result...temperatures blw
guidance for the event.

&&

Long term /Wednesday through Monday/...
not much change to the long term forecast as model guidance looks
similar to previous forecast.

General 500 mb pattern of ridging out west and troughing over the east
looks to continue through the period. Vortex develops over Hudson
Bay late this week with cold conditions persisting into early next
week. Only time periods of concern with regards to precipitation are Thursday
night into Friday as a clipper system tracks across the area...and
Monday...although there is high uncertainty with this system. Thermal
profiles are cold enough for snow Thursday night/Friday although amounts
will be light.

As for Monday...the GFS is more amplified with the 500 mb flow come early
next week and is tracking a clipper system across the Great Lakes
with redevelopment off the middle Atlantic coast. The ec being flatter
develops a low over the middle Mississippi Valley and tracks it eastward off
the middle Atlantic coast and out to sea.

Have gone below guidance for lows Wednesday night due to a deep snowpack
on the ground and good radiational cooling conds expected with high
pressure building ohd. Winds will be light so wind chills will only be a
few degrees below ambient air temperatures.

Temperatures will generally be in the 20s during the day and teens at
night...except for Wednesday night when they much of the area should drop
into single digits and Thursday/Friday with upper 20s to lower 30s and lower
to middle 30s respectively.

&&

Aviation /21z Monday through Saturday/...
** high impact snow and wind event expected from late today into
Tuesday night **

Low pressure developing off the middle Atlantic coast is expected to
track south and east of the region tonight.

LIFR conditions gradually developing from S to north through 00z.
Blizzard conditions expected at kjfk/klga/kisp/kgon by late this
evening. 1-3" of snow expected by 00z...then 2-4 inch an hour
rates develop from southeast to northwest starting around midnight.

NE winds strengthen with gusts 25-30kt by middle-late afternoon. Winds
back to the north-northeast late tonight...with gusts increasing to
25-40kt...lowest far west terminals and strongest far east terminals.

Moderate icing is likely below fl180. Moderate turbulence between
surface-fl390 with local severe possible fl200-310. Refer to zny meteorological impact statement and
significant meteorological information Victor for more information.

New York metropolitan enhanced aviation weather support...

Detailed information...including hourly taf wind component forecasts can
be found at: http:/www.Erh.NOAA.Gov/zny/n90 (lower case)

Kjfk fcster comments: conditions may briefly drop to LIFR in snow
bands this afternoon. 1-3 inches of snow expected through 00z. After
00z...heavy snow with rates of 2-4 inches per hour likely.

Klga fcster comments: conditions may briefly drop to LIFR in snow
bands this afternoon. 1-3 inches of snow expected through 00z. After
00z...heavy snow with rates of 2-4 inches per hour likely.

Kewr fcster comments: conditions may briefly drop to LIFR in snow
bands this afternoon. 1-3 inches of snow expected through 00z. After
00z...heavy snow with rates of 2-4 inches per hour likely.

Kteb fcster comments: conditions may briefly drop to LIFR in snow
bands this afternoon. 1-3 inches of snow expected through 00z. After
00z...heavy snow with rates of 2-4 inches per hour likely.

Khpn fcster comments: timing of gusts may be off by an hour or two.
Conditions may briefly drop to LIFR in snow bands this afternoon.
1-3 inches of snow expected through 00z. After 00z...heavy snow with
rates of 2-4 inches per hour likely.

Kisp fcster comments: conditions may briefly drop to LIFR in snow
bands this afternoon. 2-3 inches of snow expected through 00z. After
00z...heavy snow with rates of 2-4 inches per hour likely.



Outlook for 18z Tuesday through Friday...
Tuesday and Tuesday evening...LIFR or lower conditions with
blizzard conditions. NE-north winds g35-50 knots.
Late Tuesday night...gradually becoming VFR. Northwest winds g25-35kt.
Wednesday...VFR. Northwest winds g25-30kt possible.
Wednesday night-Thursday...VFR.
Thursday night...MVFR or lower conditions in light snow.
Friday...chance MVFR in light snow in the am. VFR with northwest winds g25-30kt in
the afternoon.
Sat...VFR.

&&

Marine...
970s low will produce storm to hurricane force conditions tonight and Tuesday.
Winds will diminish to Small Craft Advisory levels Tuesday night.

Conds will become sub-advsy on Wednesday as the storm continues to pull
away and high pressure builds from the west. The high will keep tranquil
conds on the waters through Thursday night as the high moves ohd and then
offshore. Small Craft Advisory conds return Friday into Sat as a clipper low intensifies
over the Gulf of Maine and strong high pressure builds from the west.

&&

Hydrology...
liquid equivalent amounts of 1.5 to around 2.25 inches with the
blizzard.

Ice on the Wallkill and Yantic rivers is causing minor
fluctuations in river levels at this time.

&&

Tides/coastal flooding...
a coastal Flood Warning is in effect for northern Long Island and
western New York coast within the western Long Island Sound.

For the Twin Forks of Long Island...coastal Flood Warning is in
effect.

A coastal Flood Warning for the South Shore bays of Long Island.

Coastal Flood Advisory is in effect for New York Harbor...and the CT
coasts.

The Nor'easter is expected to produce moderate coastal impacts for
parts of the region overnight into early Tuesday morning high tide.
There's the potential for flooding of vulnerable shore roads and/or
adjacent properties due to height of storm tide and/or wave action.

The uncertainty with the surge is in how quickly winds turn from
the NE to north. An earlier veering of winds to the north ahead of high
tide typically reduces surge in our region.

The most likely surge for coastal areas is:

- western Long Island Sound (ny zones)...3 to 4 feet of surge with
potential for up to 4 1/2 feet.

- Long Island Sound CT coast...2 to 2 1/2 feet of surge with potential
for up to 3 feet.

- The Twin Forks of Long Island where 3 to 4 feet of surge is possible
as water gets piled up around The Forks.

- New York Harbor and the South Shore bays...2 to 3 feet of surge.

Beach erosion and washovers are expected along ocean facing barrier
beaches of Long Island due to 7 to 12 feet waves and the high storm
tide. A few exposed Waterfront structures may be damaged.

High waves and high storm tide will also cause beach erosion along
north facing shorelines of Long Island Sound and along the Twin
Forks. A few exposed Waterfront structures may be damaged.

&&

Climate...
this blizzard has the potential to produce the largest single-
storm snowfall in NYC history. Here are the current top ten
snowfalls for the city...



Amount dates

26.9 Feb 11-12 2006
25.8 Dec 26-27 1947
21.0 Mar 12-13 1888
20.9 Feb 25-26 2010
20.2 Jan 7-8 1996
20.0 Dec 26-27 2010
19.8 Feb 16-17 2003
19.0 Jan 26-27 2011
18.1 Jan 22-24 1935 and March 7-8 1941
18.0 Dec 26 1872

&&

Okx watches/warnings/advisories...
CT...Blizzard Warning until midnight EST Tuesday night for
ctz005>012.
Coastal Flood Advisory from 1 am to 7 am EST Tuesday for
ctz009>012.
New York...coastal Flood Warning from 1 am to 7 am EST Tuesday for nyz079-
081.
Blizzard Warning until midnight EST Tuesday night for
nyz067>075-078>081-176>179.
Coastal Flood Warning from midnight tonight to 5 am EST
Tuesday for nyz075-080-178-179.
Coastal Flood Advisory from midnight tonight to 4 am EST
Tuesday for nyz072-074.
Coastal Flood Warning from 3 am to 7 am EST Tuesday for nyz071-
073-078-176-177.
New Jersey...Blizzard Warning until midnight EST Tuesday night for njz002-
004-006-103>108.
Marine...Storm Warning until 6 PM EST Tuesday for anz330-340-345-353-
355.
Gale Warning until 6 PM EST Tuesday for anz335-338.
Hurricane force wind warning until noon EST Tuesday for anz350.

&&

$$
Synopsis...jmc/24
near term...jmc
short term...jmc
long term...24
aviation...mmd
marine...jmc/24
hydrology...jmc/24
tides/coastal flooding...precipitable water
climate...

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