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000
FXUS61 KOKX 251954
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
354 PM EDT Sun Oct 25 2020

.SYNOPSIS...
High pressure to the north moves towards the Canadian Maritimes
tonight as a wave of low pressure meanders along the Middle Atlantic
coast. The low slowly lifts towards the area on Monday before
shifting offshore Monday night. High pressure then settles into
the Northeast through mid week before shifting offshore.
The remnants of Zeta and a larger low pressure system may impact
the region at the end of the week. Strong high pressure then
builds into the area over the weekend.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
High pressure to our north across southeast Canada continues to
advect cool and dry air southward under northerly flow. There is a
cold air damming signature in the pressure field from the Middle
Atlantic down into North Carolina east of the Appalachians.
This surface pattern is setting up an inverted trough along the
coast with a weak wave of low pressure developing along the
trough.

The surface high will slowly move towards the Canadian Maritimes
this evening and tonight. Warm advection and overrunning will
develop and help lower and thicken clouds through this evening.
The warm advection is stronger to our south this afternoon, but
light rain returns on Doppler Radar are having trouble moving
northward due to dry air and subsidence from the high. The
subsidence should weaken this evening from south to the north as the
high moves east. Warm advection/overrunning will be the main
forcing mechanism for light rain tonight. The light rain will
spread from south to north through the night, taking longest to
reach the ground across the interior due to the lingering dry
air. Light rain will then continue into the early morning hours.

Overall rainfall amounts will be light with around a tenth of an
inch or less across the interior to around two tenths near the
coast.

Lows will range from the lower to middle 40s inland to the upper 40s
near the coast. Temperatures could rise a few degrees early in the
morning as the flow becomes more easterly.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
Thermal forcing weakens Monday morning, which will bring an end to
the widespread light rain. The low levels will remain saturated
through the day however which will support a chance for light
rain or drizzle. The low pressure to the south will only slowly
lift towards the area in the morning and afternoon. Forecast
soundings indicate dry middle levels through the day, but with
continued easterly flow between the low pressure and high well
to the northeast, low clouds will remain in place. Slightly
warmer air pushes closer to the area through the day and with
the saturated low levels, patchy fog is possible outside of any
light rain or drizzle. Rainfall amounts will continue to be
light. Highs on Monday will be near normal in the middle and
upper 50s inland to around 60 close to the coast.

The low finally weakens and lifts northeast away from the coast
Monday night. Forecast soundings continue to indicate saturated low
levels. Mostly cloudy to overcast skies are anticipated with just a
slight chance of light rain. High pressure begins to build towards
the area late Monday night helping to shift the low level flow to
northerly. This should help to scour out some of the lingering low
level moisture. Lows range from the upper 40s to lower 50s.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
At the surface a high pressure system settles into New England
Tuesday into Wednesday. In the upper levels southwest flow continues
to bring moisture overhead. This moisture will likely manifest as
increased cloudiness though isolated light rain can quite be ruled
out. Regardless temperatures are mild in the mid to upper 50s both
Tuesday and Wednesday with overnight lows in the 40s.

Late Wednesday into Thursday as the high shifts offshore attention
shifts to the remnants of Tropical Storm Zeta and a deepening mid
level trough over the Oklahoma. Though the exact location is
uncertain, models show Zeta possibly in the right exit region of a
120 kt jet streak. This southwest to northeast jet transports the
system and moisture into the forecast area Thursday. As the low
transitions rain is likely to begin Thursday morning initially as
warm frontal showers. By the evening, precipitable water values
around 1.2 to 1.5 inches promote heavy rainfall throughout the
region. The main hazard will be nuisance flooding possible. A second
wave of moderate to heavy rain arrives Friday with the main upper
level trough.

Over the weekend a strong high pressure system builds behind the
trough into the Northeast. Dew points drop dramatically into the 20s
and 30s particularly for our inland counties. This sets up the
possibility of Freezing temperatures Saturday morning. The dry air
zeros out the rain chances through the weekend.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
High pressure builds north of the area through this evening while a
surface trough along the mid Atlantic coast resides over the region.
Low pressure will remain southeast of the area on Monday.

MVFR ceilings develop this evening, between 01-05Z. These conditions
will last through Monday morning. IFR conditions are likely to
develop Monday morning. IFR to MVFR conditions will continue into
Monday afternoon with only slight, if any improvement throughout the
day.

Mainly east winds for this evening as wind speeds will be 10-15 kt
for coastal terminals, 5 to 10 kt for terminals away from the coast.
For late tonight occasional gusts to 20 kts are expected for coastal
terminals. East winds will continue into Monday, but lighter at 5 to
10 kt.

 ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

Amendments are possible early this evening as ceilings continue to
lower. Further amendments are possible towards early Monday morning
with the likely development of IFR conditions. Any improvement from
IFR to MVFR into Monday afternoon is low confidence and would be
gradual.


.OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...
.Monday afternoon...IFR and MVFR conditions are expected with a
chance of -SHRA and -DZ.
.Tuesday...MVFR possible with a chance of showers.
.Wednesday...VFR.
.Thursday...MVFR or lower possible in RA.
.Friday...MVFR conditions possible in -RA.

Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/www.weather.gov/zny/n90

&&

.MARINE...
Long period swells subside this evening. However, seas will
remain elevated and should build to 6 to 7 ft tonight into
Monday in response to strengthening easterly flow ahead of the
an approaching low pressure system. Seas will slowly diminish
Monday afternoon into Monday night as the low moves away from
the waters. There will also be a period of wind gusts around 25
kt on the ocean as the low approaches tonight. No changes were
made to the Small Craft Advisory, which is in effect until 6 pm
Monday. Winds diminish on all waters Monday afternoon into
Monday night as the pressure gradient weakens.

Waves range 3-4 feet over the ocean with light east to northeast
winds through Wednesday. Late Wednesday southwest winds develop and
transition into northeast winds as the remnants of Zeta enter the
marine zones. Waves of 8-10 feet with wind gusts of 25 kts over the
ocean waters are possible Friday. These SCA conditions owing to the
system making its closest approach remain in place through
Saturday.

&&

.HYDROLOGY...
No hydrologic concerns through Wednesday. Heavy rain is possible Thursday
and Friday with the arrival of tropical moisture. The main
hazard will be from nuisance flooding.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT Monday for ANZ350-353-355.

&&

$$
SYNOPSIS...DJ/DS
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...DJ
AVIATION...JE
MARINE...DJ/DS
HYDROLOGY...DJ/DS