Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KOKX 130540
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
140 AM EDT Sat Oct 13 2018

.SYNOPSIS...
High pressure will build west of the region overnight into
Saturday, while an upper level disturbance passes across
overnight into Saturday afternoon. High pressure builds into the
region Saturday night into Sunday, then a cold front passes
through Monday night. High pressure then dominates the weather
pattern through Friday with the exception of a cold front moving
through on Wednesday.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Increased forecast clouds especially north and west of NYC with
slight adjustments to POPs for showers, temperatures and
dewpoints. Radiational cooling will be mitigated from the
increasing clouds from the west. Forecast overall remains on
track.

A strong northern stream shortwave approaches overnight into
early Saturday.

At the surface, high pressure builds west of the region. The
pressure gradient will decrease across the local area,
resulting in wind speeds continuing to decrease as well.

At the same time, a weak wave of low pressure, forced by the
above mentioned shortwave, will approach from the Ohio Valley and
move across the region on Saturday. The result will be increasing
cloud cover tonight with light rain showers activity developing
from W to E overnight into Saturday morning.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/...
Strong northern stream shortwave, and weak surface low reflection,
move across the region Saturday morning into early afternoon.
Model guidance is suggesting a high probability for a light qpf
event across the region in response. Rainfall should be
generally light, but high res models indicating enough
moisture/forcing/weak instability for some heavier showers
across LI/CT in the late morning/early afternoon.

Cloud cover, precip, and a cool Canadian airmass over the region
(850 hpa temps hovering around 0c) should result in an unseasonably
chilly day (around 10 degrees below seasonable) with highs
likely holding in the lower to mid 50s.

Shortwave departs Saturday night with zonal upper flow, with high
pressure building in at the surface from the west. The result
is expected to be clearing skies and diminishing winds, setting
up good radiational cooling conds across outlying areas. This
will bring the potential for lows in the mid to upper 30s across
interior and pine barrens, with first potential for frost
across the interior. Elsewhere along the coastal plain, lows
generally in the 40s elsewhere.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
High pressure builds into the region on Sunday with a mostly sunny
sky and high temperatures below normal. The high shifts offshore,
then a cold front approaches from the NW on Monday. Chances of rain
increase through the day from west to east. There`s still some
disagreement among the models regarding when the front passes
through with the highest chances of rain. Looks like it the passage
would be more likely after dark, but will cap PoPs at 50% for both
Monday and Monday night until the timing becomes more certain.
Monday`s high temperatures will be near normal.

Weak high pressure restores dry weather on Tuesday with a return to
below-normal temperatures. A cold front then passes through on
Wednesday. Models show a lack of moisture with the front, so
expecting a dry passage. Looks like the cold advection associated
with it occurs too late in the day to have much of an impact on high
temperatures, although they are still forecast to be below normal.
The cold advection and tightening pressure gradient will have an
effect on the winds, with a gusty westerly flow developing during
the day. Winds then subside Wednesday night with a chance of frost
forming in parts of the northernmost zones.

High pressure builds back in on Thursday with even cooler
conditions. Highs averaging only in the mid 50s. This will lead into
another chilly night with lows ranging from the mid 30s to mid 40s.
The high pressure center will then be offshore on Friday with a
milder return SW flow helping highs reach 55-60, but still at least
5 degrees below normal.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
An upper level disturbance will move across the area this
morning with a chance of showers.

VFR conditions with ceilings around 3-4 kft in the morning and
4-5 kft in afternoon. There is a low chance that a few location
could briefly have MVFR ceilings with the showers.

N-NW winds less than 10 kt overnight will veer to the W-NW by
daybreak, gusts up to 20 kt will be likely behind the
disturbance.

.OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
.Sunday night...VFR.
.Monday...Chance of MVFR in showers. SW gusts 20kt.
.Tuesday and Wednesday...VFR.

&&

.MARINE...
Seas have fallen below SCA levels on the ocean waters and will
continue to subside through this morning, thus the advisory has
been cancelled. A weak low pressure trough moving across
Saturday and high pressure building in Sat Night into Sunday
will keep conditions below SCA levels. Low prob of marginal SCA
gusts late Sat/Sat eve evening in wake of weak low.

High pressure will keep winds and seas below SCA levels Sunday, then
the next cold front passing through on Monday night will bring SCA
conditions to most of the waters Monday afternoon and night. Seas
above 5 ft then linger on some of the ocean waters Tuesday morning
before a brief period of sub-SCA conds lasting through Tuesday
night. SCA conds, and possibly even some gales, arrive on Wednesday
with another cold front.

&&

.HYDROLOGY...
No hydrologic issues expected through middle of next week.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO35 (162.55 MHz) remains off
the air for an extended period of time.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.