discussion on 2023-10-11

000
FXUS61 KOKX 111129
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
729 AM EDT Wed Oct 11 2023

.SYNOPSIS...
Weakening low pressure north of the Great Lakes will track
slowly across eastern Canada through the end of the week. At
the same time, weak high pressure will set up over the northeast
through Friday. Low pressure then passes to our south this weekend.
Weak high pressure will be left in its wake on Monday before
another area of low pressure potentially impacts the region on
Tuesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Forecast on track early this morning. The main weather feature
over the next few days will continue to be low pressure spinning
across eastern Canada. A shortwave passes offshore early this
morning. The cyclonic flow aloft will bring in varying amounts
of cloud cover to start the day. Subsidence behind the shortwave
and rising heights aloft into the afternoon should yield partly
cloudy to mostly sunny conditions in the afternoon.
Temperatures will reach the middle and upper 60s for most
locations with some of the usual warm spots in NE NJ touching
70. These readings are a few degrees above normal for this time
of year.

Dry and mostly clear conditions prevail tonight as a weak high
pressure settles over the area from the SW. Interior locations
and the Long Island Pine Barrens will likely fall into the
lower to middle 40s with upper 40s to lower 50s most elsewhere.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Low pressure begins to shift east towards Northern New England
Thursday and then to the Maritimes on Friday. At the same
time, another upper level closed low will track eastward into
the northern and central Plains through Friday. Brief ridging
builds over the Ohio Valley into the northeast ahead of the
system on Friday. The upper low then begins to interact with the
closed low over the Maritimes Friday night, pushing the
associated frontal system and low pressure towards the region
for the first part of the weekend.

Middle level moisture is progged to increase late Thursday
into Thursday night as a broad shortwave axis moves across the
area. Increasing confluent flow aloft between the building
heights to our west and departing closed low over the Maritimes
will gradually push this moisture south and east of the area.
However, mostly cloudy conditions look likely for the southern
half of the area Thursday night. The subcloud layer remains dry
and there is little forcing to support any precip.

High pressure will briefly build out of southern Canada ahead
of the next upper low on Friday. The confluent flow aloft will
likely lead to mostly sunny conditions for Friday. Clouds
should begin to increase from west to east Friday night. A
model consensus blend indicates increasing chances for rain
late at night into early Saturday as warm advection commences.

Highs on Thursday will be a few degrees above normal in the
middle and upper 60s. Thicknesses lower on Friday which should
bring temperatures closer to normal in the lower to middle 60s.
Nighttime temperatures are expected to be in the 40s inland and
lower 50s closer to the coast.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
A shortwave embedded in a longwave trough at 500mb digs through
the Ohio River Valley and Mid-Atlantic on Saturday before
emerging off the eastern seaboard early Sunday, then lifting NE
Sunday night. Meanwhile, a blocking 500mb low lingers over the
southern Canadian Maritimes through the weekend before shifting
NE. A spoke of energy rotates through the longwave trough Monday
and Tuesday, tracking through the Mid-Atlantic.

At the surface, low pressure to the west transfers energy to a
developing low off the Mid-Atlantic coast that passes to our SE
Saturday night into Sunday morning. Rain becomes likely during
the day Saturday and remains likely into Saturday night with
rain chances lowering on Sunday. Rain intensity appears to be
more likely on the light to moderate side. Additionally, this
system is starting to look more progressive as the 500mb low
over the south Canadian Maritimes and spoke of energy dropping
south through the eastern Great Lakes Region help steer the
storm center eastward to our south before it gains strength
while moving NE. With these in mind, impacts here still appear
to be more on the minor side. See the hydrology section below
for more details.

Cyclonic flow aloft remains on Monday, sustaining a chance of
showers. Another low pressure system may then begin to take
shape near us or to our south on Tuesday with the spoke of
energy moving through the Mid-Atlantic. More rain will be
possible.

High temperatures Saturday through Tuesday will remain below
normal due to the rain and clouds - generally in the mid 50s to
around 60.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --Weak high pressure remains in place today.

VFR. Light WSW-SW winds this morning, backing more SW this
afternoon and increasing to around 10 kt. Sea breeze expected
for KJFK and KLGA this afternoon, shifting winds south.


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

Winds might be more SW than forecast this morning. Chance that
sea breeze does not reach KJFK and more so KLGA this afternoon.
Chance that sea breeze shifts winds SE at KEWR and S-SE at KTEB
this afternoon.

OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...

Thursday: VFR.

Friday: Mainly VFR. MVFR possible late Friday night with a chance of
rain.

Saturday-Sunday: MVFR/IFR in rain. E-ESE winds 10-15G20KT Saturday.
ENE-NE winds 15G25KT Saturday night. NE-N winds 15G20KT Sunday.

Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --

&&

.MARINE...
A relatively weak pressure gradient will lead to winds and seas
below SCA levels through the remainder of the week. Low pressure
then approaches the Mid-Atlantic coast Friday night into
Saturday with winds veering ENE and increasing through the day
and night as a frontal system approaches us from the west. This
will help push wave heights above 5 feet over the ocean Saturday
night, with advisory-level wind gusts on most, if not all
waters into Sunday.

&&

.HYDROLOGY...
No hydrologic impacts are expected through Friday night.

Current forecast has an inch to two inches of rain for Saturday
through Sunday. Based on current flash flood guidance, there is
only a low chance of flash flooding. Still can`t rule out
future changes in guidance regarding potential rain amounts, and
also need to consider that soil moisture, while decreasing
through Friday, will still be high enough to not completely rule
out isolated flash flood potential. Impacts including
minor/poor drainage flooding as well as minor flooding of some
of the quicker responding rivers and streams still appear to be
the more likely scenario.

&&

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

&&

$$

SYNOPSIS...JC/DS
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...JC
AVIATION...JC
MARINE...JC/DS
HYDROLOGY...JC/DS