Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service New York New York
408 PM EST Tuesday Jan 27 2015

Synopsis...
high pressure builds tonight and Wednesday behind the noreaster.
High pressure retreats to the northeast Thursday...as a clipper
system approaches from the northwest. This storm impacts the area
Thursday night and Friday. High pressure builds in from the west
Friday night through Saturday night...then slides to the east on
Sunday. A storm system approaches fromm the south late Sunday...then
passes near or over the area Monday...then exits to the northeast
Monday night. High pressure then builds in on Tuesday.

&&

Near term /until 6 am Wednesday morning/...
lingering snow...in disorganized bands behind the
storm...associated with upper trough...will continue this evening
before tapering off late tonight. Will maintain Winter Storm
Warning for southeast CT and eastern Li...with winter weather advisories SW
CT and western Suffolk.

Would generally expect an additional 1 to 3 inches of snow in any
of these bands. In addition...blowing snow will reduce
visibilities into tonight...mainly for CT and Li where higher snow
amounts were observed.

Otherwise...cold air behind this storm will move in on gusty northwest winds.
Expect low temperatures ranging from around 10 degrees across the
interior to upper teens near the coast.

&&

Short term /6 am Wednesday morning through Wednesday night/...
upper trough departs with ridge building in late Wednesday and
Wednesday night. Dry weather is expected...with gusty northwest winds
persisting. These winds...combined with chilly temperatures will produce
wind chill readings in the single digits to teens.

Morning clouds give way to sunshine from west to east.

High temperatures middle 20s to around 30...with lows from zero to the
teens. Good radiational cooling conditions are anticipated due to
clear skies...lightening winds and snow cover.

&&

Long term /Thursday through Tuesday/...
northern stream ridging exits to the east on Thursday...with a
northern stream shortwave quick on its heels. For now appears
Thursday should be dry...except for a slight chance of light snow
late in the afternoon over far western zones. This shortwave lifts
through Thursday night followed by the approach of a deeper full
latitude trough...whose axis crosses the area on Friday.Have likely
probability of precipitation for light snow as a result Thursday night with the
shortwave...then chance probability of precipitation on Friday with the upper trough. At
this time it appears that the area will experience a sub-advisory
(less than 3 inch) snowfall from Thursday night through Friday.

For highs on Thursday a blend of mav/met/ecs guidance...with NAM
2-meter temperatures and a mix down from 975 hpa per BUFKIT
soundings were used. Highs should be around 5 degrees below normal.
The minimum of mav/met guidance...the previous forecast and NAM
2-meter temperatures was used for lows on Thursday night...then a
degree was subtracted to reflect the influence of snow cover. Lows
should be slightly above normal. For highs on Friday a blend of
mex/men/ekd/ece/ecm/wpc guidance with NAM 2-meter temperatures and a
mix down from 900-875 hpa was used...with values forecast to be a
few degrees below normal.

Deep layered ridging builds in Friday night through Saturday
night...with its ridge axis sliding to the east on Sunday. It should
be dry Friday night-Saturday night due to subsidence underneath the
ridge.

There are some differences in solutions for a storm system forecast
to impact the area early next week. The European model (ecmwf) is the warmest
solution...the Canadian the coldest and fastest...and the GFS in
between. Noting the gefs ensemble mean supports a solution to the southeast
of the GFS...leaned towards a slightly cooler version of the GFS
solution. So have a rain snow mix near the coast and snow across the
interior from late Sunday into Monday.

Ridging begins to build in Monday night and Tuesday...with a dry
forecast as a result.

For temperatures Friday night-Tuesday a blend of
mex/men/ekd/ece/ecm/wpc guidance was used with temperatures forecast
to be below normal during this time frame.

&&

Aviation /21z Tuesday through Sunday/...
low pressure east of Cape Cod will track northward into the Gulf of ME tonight and
into the Maritimes on Wednesday.

Mainly VFR across the city and western arpts through 23z...then stratus may
again develop thereafter. Some light snow or flurries possible.

Elsewhere...mainly MVFR through the taf period with pockets of IFR or
lower in light to MDT snow early this evening.

Northwest winds around 330 true through the taf period. Strongest flow through
this evening.

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: may remain VFR tonight if stratus does not
redevelop.

Klga fcster comments: may remain VFR tonight if stratus does not
redevelop.

Kewr fcster comments: may remain VFR tonight if stratus does not
redevelop.

Kteb fcster comments: may remain VFR tonight if stratus does not
redevelop.

Khpn fcster comments: may remain VFR tonight if stratus does not
redevelop.

Kisp fcster comments: edge of light snow may remain just east of the Airport
this evening.

Outlook for 18z Wednesday through Saturday...
Wednesday...VFR. Northwest winds 15-25kt.
Thursday night...MVFR or lower in snow.
Friday...MVFR possible in the morning with snow. Northwest winds 20-30kt.
Sat...VFR.
Sun...MVFR or lower possible.

&&

Marine...
deep low pressure east of Cape Cod will depart to the northeast as
high pressure gradually builds in from the west.

Gusty northwest winds will diminish this evening as the pressure
gradient relaxes somewhat. Gale Warning remains in effect through
the evening for the eastern waters...with Small Craft Advisory gusts continuing
tonight and through Wednesday for the other waters. Seas gradually
subside...but remains rather rough through Wednesday.

Winds diminish further Wednesday night as high pressure builds.

A relatively relaxed pressure gradient will produce sub-small craft
conditions over the waters Thursday and Thursday evening. The
pressure gradient begins to increase Thursday night...with at least
Small Craft Advisory level seas possible on the coastal waters late Thursday night.

A tightening pressure gradient and strong low level cold advection
makes gale conditions probable on all waters from Friday and Friday
night.

Winds diminish Saturday as high pressure builds in...with only Small Craft Advisory
level seas possible on the coastal ocean waters by afternoon. Sub
Small Craft Advisory conditions should develop on all waters by late Saturday
night...and continue on Sunday...with a relaxed pressure gradient
forecast to be over the region.

&&

Hydrology...
liquid equivalent amounts will be less than a tenth of an inch
for eastern locales this evening. No Hydro issues are expected.

No significant precipitation is expected from Thursday through early
Sunday. Some light snow is likely Thursday night and Friday...but no
hydrologic impact is expected.

There is the potential for at least a half an inch of liquid
equivalent to fall from late Sunday and Monday. Some or most of this
is currently forecast to be in the form of frozen precipitation...so
little or no hydrologic impact is expected at this time.
However...if the warmest solution with this system verifies...then
most of this could be of liquid form...and could produce hydrologic
concerns...especially over areas just receiving a foot or more of
snow.

&&

Okx watches/warnings/advisories...
CT...Winter Weather Advisory until midnight EST tonight for ctz005-
006-009-010.
Winter Storm Warning until midnight EST tonight for ctz007-008-
011-012.
New York...Winter Weather Advisory until midnight EST tonight for nyz078-
080.
Winter Storm Warning until midnight EST tonight for nyz079-081.
New Jersey...none.
Marine...Small Craft Advisory until 6 PM EST Wednesday for anz335-338-
345-353-355.
Gale Warning until midnight EST tonight for anz330-340-350.

&&

$$
Synopsis...maloit/pw
near term...precipitable water
short term...precipitable water
long term...maloit
aviation...jmc
marine...maloit/pw
hydrology...maloit/pw

National Weather Service Glossary of Abbreviations