Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 261033
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
533 AM EST Sun Feb 26 2017

.SYNOPSIS...
High pressure builds along the Eastern Seaboard today. The
strengthening high drifts over the Atlantic on Monday. A warm
front sets up in the vicinity on Tuesday, followed by a cold
frontal passage Thursday. A clipper may impact the area by the
end of the week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The forecast was on track with no major changes made. Low
pressure was over the Canadian Maritimes this morning, with the
associated cold front extending southward over the Atlantic.
Some snow showers and flurries were noted across Upstate New
York, but downsloping flow and subsidence are expected to keep
the forecast area dry today. A few flurries cannot be ruled out
of a potential broken deck around 4500 feet.

WNW winds this morning should gust to 20-35mph, strongest near
the coast and over NYC. Wind gusts should diminish this
afternoon, as 950-850 winds diminish to around 25 kt by evening.

The guidance was in good agreement so a blend was used for
temperatures.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
After the diurnal cumulus dissipates this evening, model time
heights suggest the mid and high clouds will hold off for all
if not most of the night. With winds decoupling, especially in
the usual outlying spots, temperatures were nudged slightly
below guidance.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
The forecast was generally on track for the extended. The most
significant change was to include a chance for snow on Friday.

An increase in mid level moisture will produce overcast skies
by the end of Monday. A lack of deep moisture and lift are
limiting factors for the development of precipitation at this
time. The forecast has therefore been kept dry through Monday
night. Rain chances increase Tuesday and Wednesday as Gulf
moisture infiltrates the region. Gusty winds of 35-45 mph are
likely Thursday with strong low level cold advection behind the
cold front and winds from 950-850 hPa progged at 40-50kt. There
is some potential for wind advisory criteria to met both in
coastal areas and at higher elevations. After the main band of
rain with the front, there could be some residual scattered
showers with steepening lapse rates and strong vorticity
advection. With the cold air pouring in, these showers could
mix with or change to snow. The passage of an Alberta Clipper
then appears to be a little more likely on Friday per the 00Z
model suite. As a result, a chance of snow has been introduced
to the forecast. Cold on Saturday with wind chills potentially
in the teens for most of the day.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
High pressure builds to the Mid-Atlantic coast into tonight.

VFR through the TAF period. Ceilings of 3500-5000 feet are possible
through this afternoon.

Gusty WNW winds through 00Z, with gusts diminishing through the day.
The flow will back slightly to the west and lighten significantly
this evening.

.OUTLOOK FOR 06Z MONDAY THROUGH THURSDAY...
.Late Tonight-Monday evening...VFR. SW winds G15-20KT possible
during the day on Monday.
.Late Monday night-Wednesday...Chance of MVFR or lower. LLWS
possible Tuesday-Wednesday.
.Wednesday night...IFR or lower possible. SW winds G15-25KT
possible along coast.
.Thursday...MVFR possible. W-WNW winds G30-40KT probable.

&&

.MARINE...
Strongest wind gusts over the waters will be this morning, then
diminishing in the afternoon as low level winds diminish to around
25 kt. Winds continue to diminish tonight from W to E. Have extended
the SCA through midnight over the western waters and until 6am
Monday on the eastern waters as a result.

There is some question on Monday as to whether or not we mix down
any of the 25-30KT low level winds, maybe by late afternoon - with
the best chance closer to the coast. Given confidence in occurrence
of SCA of less than 80 percent, did not extend SCAs over the eastern
waters into Monday.

Low level mixing should be limited Monday night and Tuesday, so even
though low level winds are 25-35 kt, have gone with a sub-small
craft forecast.

The pressure gradient tightens Tuesday night, allowing for at least
seas to possibly build to SCA levels east of Moriches Inlet.

The pressure gradient continues to tighten on Wednesday, with SCA
conditions likely on the coastal ocean waters, and possible on the
non-ocean waters. These conditions should continue through Wednesday
night.

With strong cold advection forecast for Thursday and low level winds
of 40-50kt progged in some guidance, gales are likely on the coastal
ocean waters and possible on the non-ocean waters. There is a small
chance for gusts to storm force as well on the coastal ocean waters.
These threats will be highlighted in the HWO.

&&

.HYDROLOGY...
The next chance for widespread precipitation is the middle of
next week, where around and inch of rain is possible.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until midnight EST tonight for ANZ335-338-
     345-355.
     Small Craft Advisory until 6 AM EST Monday for ANZ330-340-350-
     353.

&&

$$
SYNOPSIS...12
NEAR TERM...12/Maloit
SHORT TERM...12
LONG TERM...12/Maloit
AVIATION...Maloit
MARINE...Maloit
HYDROLOGY...12


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