Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 011745
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
145 PM EDT Sat Oct 1 2016

.SYNOPSIS...
Little change over the weekend with high pressure to the northeast
and low pressure over the Ohio Valley. The low will then slowly
weaken as it moves toward the region on Monday. Meanwhile, high
pressure will build from the north from Monday night through the
middle of the week, then retreat to the northeast later next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Drizzle has become more patchy in coverage along with the patchy
fog. There is some light rain across Eastern Long Island and SE
Connecticut with otherwise not much else in terms of radar
reflectivity this afternoon. Temperatures and dewpoints were
slightly adjusted in addition to the drizzle to reduce the areal
coverage of that. The rain was also lowered in terms of POPs as
the rain models had been showing has not materialized but the
chances do increase by evening as atmospheric column becomes more
moist.

Moisture is getting trapped by the NE flow underneath an
inversion that was conveyed by the morning OKX sounding to be at a
height of just under 2000ft. The region is in between a high
across the Canadian Maritimes and a low in the Ohio Valley.

The upper air pattern will be slow to breakdown with a slowly
filling upper low over the Ohio Valley, and a weakening upper
ridge over the western Atlantic that extends back NW across New
England into Eastern Canada. At the surface, high pressure to the
northeast and low pressure over the Ohio Valley both gradually
weaken. More importantly, this will mean a continuation of a NE
flow being overrun by a southerly winds aloft. Winds though will
be considerably lighter than recent days.

Its real difficult to hone in on any one feature for lift today,
but overall there is weak warm advection and saturated low levels.
Thus, expect a continuation of occasional light rain, drizzle,
and patchy fog.

While its warm aloft, the cool NE flow and cloud cover will keep
highs about 5 degrees below normal, generally the lower 60s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
More of the same tonight through Sunday night with a chance of
light rain, drizzle, and patchy fog. However, with the gradual
weakening of both the high to the north and the upper low over the
Ohio Valley, the activity should dissipate in coverage and with
time become more spotty in nature.

Highs on Sunday will be closer to normal as the low-level cold
air across the region begins to slowly erode. Lows will still be
several degrees above normal due to the nighttime cloud cover.

For Mon, although low levels should continue to dry, as upper
trough energy moves overhead, diurnal iso-sct shower activity
possible with cold pool/diurnal instability interacting with
residual moisture.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
For Tue, diurnal iso-sct shower activity continues with cold
pool/diurnal instability interacting with residual moisture.

Thereafter, models in good agreement with deep layered ridging
developing for mid to late week with region experiencing a
Canadian Maritime airmass. Meanwhile, the evolution of Hurricane
Matthew will be closely monitored, with forecast sensitivity tied
to the evolution of upper energy as it moves offshore the east
coast mid to late week, the mid to late week evolution of the
trough energy coming into the West Coast this weekend, and the
development of Matthew itself. Refer to the National Hurricane
center forecasts for the latest information.

Temps near or slightly below seasonable through the period.

&&

.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
The terminals will remain between high pressure to the northeast and
low pressure to the west into Sunday afternoon.

MVFR this afternoon except at KISP (IFR) and KSWF (LIFR), expect
all terminals to become IFR/LIFR tonight, last at KGON. Conditions
should improve to MVFR at KLGA/KJFK/KEWR around midday Sunday,
remaining IFR elsewhere. There will be some variablity +/-
a category from time to time, most likely at the city terminals

NE winds around 10-15kt through this afternoon - with gusts to
around 20kt at KGON. Speeds should decrease to under 10 kt
tonight, and should remain so into Sunday afternoon.

.Outlook for 18Z Sunday through Wednesday...
.Sunday afternoon/night...MVFR or lower possible with spotty light
rain or drizzle.
.Monday-Tuesday...Mainly VFR with isolated to scattered showers
possible. NE-E winds g15-25kt possible Monday Night/Tuesday.
.Tuesday night-Wednesday Night...VFR.
.Thursday...Low chance of MVFR or lower late, otherwise VFR.

&&

.MARINE...
Northeast winds and waves will diminish into tonight. However,
SCA remains on the ocean waters through late tonight as waves will
be slow to drop below 5 ft. Winds should remain below 25 kt
through Tuesday night.

A prolonged period of SCA is possible from Tuesday afternoon
through Thursday night on the ocean waters as seas build to 5 to 9
ft through this time period. NE Winds increase Tuesday, with 25
kt or higher possible for the ocean waters by Wednesday morning
through Thursday.

&&

.HYDROLOGY...
A quarter inch or less of rainfall is expected through Sunday in
mainly light rain/drizzle. An additional tenth of an inch is
possible on Monday in isolated showers.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 5 AM EDT Sunday for ANZ350-353-355.

&&

$$

SYNOPSIS...DW
NEAR TERM...JM/DW
SHORT TERM...DW
LONG TERM...NV
AVIATION...Maloit
MARINE...JP
HYDROLOGY...DW



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