Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 150037
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
837 PM EDT Sat Oct 14 2017

.SYNOPSIS...
Weak high pressure builds into the region tonight and remains
overnight, then drifts east during Sunday. A cold front
approaches on Sunday and passes through the area late Sunday
night. High pressure will build over the region for the rest of
the week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Updated the temperature and dew points, along with the overnight
lows as clouds will be moving into the region along with fog.
Weak low level warm advection will also be setting up after 03Z.
So, temperatures and dew points are expected to remain nearly
steady from current levels. However, temperatures may begin to
rise, especially along the coast, late tonight.

Vis in the fog was lowered in the grids to a half a mile across
ern CT and LI. A broad upper ridge over the Southeast and Mid
Atlantic states begins to give way to an approaching upper
trough over the Midwest. This will result in a strengthening,
deep-layered SW flow aloft and unseasonably warm and humid
conditions for the remainder of the weekend.

At the surface, the wave of low pressure that brought rain to
eastern portions of the tri-state area on Saturday will pass
well east of New England. In its wake, weak high pressure will
build across the area tonight. The combination of moist low-
levels and light winds will result in low clouds and areas of
fog forming during the overnight hours. There is some
uncertainty on how dense the fog gets and this may depend on how
much clearing the area sees into early this evening. A dense
fog advisory may be needed later tonight. Additionally, with the
strengthening low-level southerly above the surface, drizzle
will be possible as well.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
After some morning fog/drizzle, skies clear out with mostly
sunny skies by afternoon. Sunday will be well above normal with
temperatures generally in the mid to upper 70s. Gusty S-SW winds
may get up to 30 mph in the afternoon.

An upper trough and cold front will impact the area Sunday
night with increasing clouds and a chance of showers. The best
chance may actually be across eastern areas due to the
availability of deeper moisture. Instability though is weak, so
no thunderstorms are forecast. Rainfall amounts also look to be
light with a lack of deep forcing. The cold front passes east of
the area by daybreak Monday with strong cold advection and
gusty NW winds.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
A sprawling area of high pres will build from the w on Mon,
then set up over the area thru Sat. A residual shwr is possible
Mon mrng, otherwise it will be a breezy day with mixing likely
abv h85. This will allow for temps to peak in the 60s. For Mon
ngt, it appears the winds will stay up, especially along the
coasts, limiting temp drops. A blend of guidance was used. If
winds decouple, fcst temps will need to be lowered and there
could be some patchy frost in the normally colder outlying
spots. The high builds in for the rest of the week keeping the
area dry and mostly clear. A blend of the guidance was used for
temps, with readings quickly shooting abv average from midweek
on.

&&

.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
A weak surface pressure gradient will be across the region
through late tonight as high pressure over the northern Atlantic
moves well off shore and low pressure moves into the Great
Lakes. The low moves into southeastern Canada Sunday as a cold
front approaches.

Forecast timing of lowering ceilings and visibilities this
evening is uncertain and difficult. Initially, early this
evening conditions will be variable from MVFR to VFR ceilings
with local areas IFR at times. Conditions are expected to lower
with widespread IFR developing in fog, stratus, and areas of
drizzle. Areas of LIFR and likely with even VLIFR in
visibilities at times.

Conditions improve slowly after sunrise Sunday, eventually
becoming VFR, with the exception of KGON where VFR is not
expected until mid afternoon.

Winds will be light and variable to calm, with a light
southerly flow developing along the south coast of Long Island
late tonight. S to SW winds increase Sunday to 10 to 15 KT with
gusts developing early in the afternoon, gusting 18-25 KT.

.OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...
.Sunday Night...VFR early, then a chance of showers after 03Z with
MVFR conditions. SW winds G20-25KT early in the evening. Winds
shift to NW after 08Z and gust 20-25KT.
.Monday...Chc early AM showers and MVFR/IFR, becoming VFR. NW
winds G20-25KT.
.Tuesday-Thursday...VFR.

&&

.MARINE...
Marginal SCA seas will continue on the ocean waters tonight due
to a SE swell.

SCA winds and seas expected to build on the ocean in a
strengthening SW flow ahead of an approaching cold front Sunday
aft/eve, and then likely with the NW flow in its wake late Sun
Night into Mon morning. SCA gusts are likely on all waters, pre
and post frontal.

Winds and seas will remain at sca lvls Mon, then subside Mon
ngt. Winds and seas will then remain blw sca lvls for the rest
of the week.

&&

.HYDROLOGY...
No hydrologic issues expected through the end of next week.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from noon Sunday to 6 AM EDT Monday for
     ANZ330-335-338-340-345.
     Small Craft Advisory until 6 PM EDT Monday for ANZ350-353-355.

&&

$$



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