Area Forecast Discussion
Issued by NWS Upton, NY-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 080533
Area Forecast Discussion
National Weather Service New York NY
1233 AM EST Thu Dec 8 2016
Weak high pressure builds in tonight...followed by a series of
cold fronts cross the area Thursday through Saturday. High
pressure follows for Saturday night into Sunday. This moves
offshore and gives way to low pressure impacting the Tri-State
from Sunday night into Monday night. High pressure returns Tuesday
into Wednesday next week.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SW flow aloft will maintain areas of mid to high clouds
overnight. With no shortwaves of note embedded in the flow and
low-level westerly flow...drying conditions expected overnight.
With breaks of cloud cover and light winds, brief windows for
radiational cooling should allow temps to fall into the mid-upper
20s across interior portions of the Tri-state. With dewpoints
well into the 30s today...patchy black ice is likely in these
areas. If clearing is more widespread, black ice potential and
areal coverage will increase across the outlying areas of the
Lows generally in the mid to upper 20s across interior...and lower
to mid 30s for the coast.
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
A northern stream trough builds into the area Thursday and
Thursday night, with multiple shortwaves passing over the area as
the push around the base of the trough. The first shortwave passes
mainly to the north on Thursday and the second on Thursday night.
The passage of each shortwave will usher in a shot of
progressively colder air.
Dry low then mid levels should keep all areas dry through Thursday
evening. It appears that there should be sufficient moistening of
the low-mid levels by late Thursday night to warrant slight chance
of snow showers over the NW 1/3 of the CWA with flurries possible
elsewhere in response to the second shortwave.
Helping to usher in the cold air will be gusty w-nw winds
increasing to 20-30 mph Thursday night - with wind chills mainly
in the teens to lower 20s just before sunrise Friday morning.
Highs Thursday were based on a blend of MAV/ECS/MET guidance, NAM
2-meter temperatures and a mix down from 925-850 hPa per BUFKIT
soundings. Highs should be near normal - with some falling
temperatures by mid-late afternoon - especially over western
For lows Thursday night, a blend of MAV/MET guidance and NAM
2-meter temperatures was used, with readings around 5 degrees
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Overall a colder weather pattern is shaping up across the region for
the long term as conveyed by the upper level jet stream. For most of
the time, this jet will be situated south of the region.
In the mid levels, a fast quasi-zonal flow Friday through the
weekend will become more amplified next week. A small less amplified
shortwave moves across Saturday with a stronger one moving across
Monday through Monday night. Forecast ends with large amplified
trough or cutoff upper level low in Southeast Canada to the
At the surface, a series of cold fronts move across Friday night
through Saturday. High pressure builds Saturday night through early
Sunday with a low pressure area then traveling towards the region
Sunday night through Monday as the high slides well offshore.
Uncertainty on exact position of surface low. For Monday night
through mid next week, high pressure returns, building in from the
west. Again, uncertainty here with position of high pressure and
whether it moves closer to region or stays farther west of the area.
In terms of weather, much colder air is expected Friday through
Saturday night. Temperatures do not get that much warmer for next
week, although Monday, with the development of return southerly
flow, temperatures are expected to be well into the 40s for a
majority of the region. Otherwise, looking at temperatures during
the day mainly 5-10 degrees below normal. In terms of precipitation,
snow showers are possible Friday and Saturday with a more widespread
precip event expected Sunday afternoon through Monday evening,
mainly stratiform. Uncertainty with position of parent low with
large differences in terms of precip. For example, latest ECMWF, 12Z
Wednesday, shows low well to the west, keeping mainly a rain event,
while other models show more of a snow potential inland. All
generally show more rain at the coast. Too early to tell with exact
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR through the TAF period as high pressure slowly builds through Thursday.
Light and variable winds for all terminals tonight. However, there
could be brief periods of WNW-NW winds for the city terminals, mainly
after 06, and they should only be 5-10 kt. Winds back to the W
Thursday, with gusts 20-25 kt.
.OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY...
.Thursday Night...VFR with W-NW G20-25KT. Flurries possible
.Friday...VFR with NW gusts 25-30KT, diminishing to around 20KT at
.Sunday...Mainly VFR, slight chance of -SN in MVFR inland.
.Monday...MVFR or lower possible in chance rain/snow mix inland and
chance of rain near coast.
A relaxed pressure gradient will keep winds to 10 kt or less
through Thursday morning. Seas have fallen below 5 ft, thus the
small craft for hazardous seas on the ocean waters has been
After a brief sub-sca respite late tonight into Thu morning...the
pressure gradient tightens sharply Thursday afternoon and remains
fairly tight over all waters Thursday night. As a result expect
gusts to 25-30kt on the coastal ocean waters Thursday afternoon
and on all waters Thursday night.
Active period on the waters with at least SCA conditions Friday
through Saturday. Gales will be possible Friday through Friday night
for all waters. Sub SCA conditions mostly Saturday night through
Sunday with high pressure more in control. SCA conditions resume
Sunday night and continue into early next week, mainly on the ocean.
It should be dry through Thursday evening, then mainly dry late
Thursday night through Sunday.
There is a chance of a widespread 1/2 inch or more of precipitation
from Sunday night through Monday.
The New York City transmitter, KWO35, is off the air. Time for a
return to service is unknown.