Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
937 PM EST Thursday Nov 27 2014
a trough of low pressure will move across the area tonight followed
by high pressure Friday through Saturday. A warm front will move
northeast across the area followed by a cold front Monday. High pressure
follows Tuesday and Wednesday.
Near term /until 6 am Friday morning/...
have adjusted pop and weather grids to reflect current trends.
Have increased pop across New London County with snow showers.
Little to no accumulation is expected. Have also removed slight
chance probability of precipitation for snow showers from the city north and west. Even
with short wave trough across western PA...air appears to be
drying out across eastern PA and western New Jersey and do no expect any
of the activity with the trough to make it into the region.
Have also issued an Special Weather Statement to account for melted snow refreezing
overnight across the interior.
Clouds will remain in place as low pressure develops off the NC
coast and moves NE. Models show the development of an inverted
trough developing northwest from this low toward southeast New England. This low
level convergence could produce some light snow showers across
eastern Long Island and southeast CT overnight.
Low temperatures tonight will fall into the 20s except right
around 30 degrees in NYC.
Short term /6 am Friday morning through Friday night/...
Friday...a cold Canadian high pressure system will follow the passage of the
upper level trough bringing a reinforcing surge of cold air. Northwest
winds of 10-20 miles per hour will bring wind chills down into the teens and 20s
to start the day before rising into the 30s during the afternoon. Another
cold day is on tap with temperatures averaging around 10 degrees below normal.
Friday night...strong radiational cooling will result as surface winds
decouple from the upper flow as high pressure passes overhead. Lows
are forecast to dip into the teens and 20s area wide.
Long term /Saturday through Thursday/...
a zonal flow will develop this weekend with several fast moving
frontal systems to impact the area through the upcoming week. Pacific
short wave energy will phase with polar jet energy with a cold
frontal passage late Monday...and another Wednesday aft/eve. Light to
moderate warm advection precipitation precedes each system with a brief mix
of frozen precipitation at the onset possible across the interior before
Thermo profiles warm. Sun morning and Tuesday night are the times of
interest. The latter is potentially the more significant of the two
as it preceded by a transient 1045 mb high moving across New
England. Warm sector rain or showers will precede each cold
For the most part...looking at slightly above normal temperatures through
the period due to the progressive flow...the exception being Sat at
the start of the period with residual cold air in place...and Tuesday
following the Monday cold frontal passage.
The 12z GFS and European model (ecmwf) are in close agreement with small timing
differences with the frontal systems. The European model (ecmwf) is also more
amplified with the upper trough moving across eastern Canada and the
NE on Wednesday. Thus...it is more aggressive with the warm advection and
amount of quantitative precipitation forecast.
Aviation /03z Friday through Tuesday/...
a high pressure ridge builds in through Friday.
Mainly VFR...except for kswf where there is some weak moist
flow...and at kgon where -sn is slowly exiting. All areas expected to
improve to VFR by 6-7z.
VFR Friday and Friday night.
Northwest winds blw 10 knots tonight...then gusts up to 20 knots Friday.
Outlook for 00z Sat through Tuesday...
Sun night-Mon...MVFR possible with a chance of rain showers.
all small craft advisories were cancelled through tonight for the
Atlantic Ocean coastal waters except from Moriches Inlet to
Montauk pt...where they were extended until midnight Sat.
Small craft advisories were issued for wind gusts of 25 knots...
6 am - 7 PM Friday from Sandy Hook New Jersey to Fire Island Inlet New York
6 am - midnight Sat from Fire Island Inlet east to Montauk
pt...eastern Long Island Sound and gardiners and Peconic bays
Another surge of cold air is forecast to produce northwest winds of 15-25
knots by sunrise Friday.
Winds and seas will subside...especially after midnight Saturday
as high pressure passes over the coastal waters.
Ocean seas/winds could again reach marginal Small Craft Advisory levels Sat night
into Sunday night via a moderate SW flow. Small Craft Advisory seas may linger on
the ocean into Monday. Sub-Small Craft Advisory conditions are forecast from Monday night
no significant precipitation is forecast during the next 7 days.
Marine...Small Craft Advisory from 6 am Friday to midnight EST Friday
night for anz330-340-353.
Small Craft Advisory from 6 am to 6 PM EST Friday for anz355.
Small Craft Advisory until midnight EST Friday night for