000
FXUS61 KOKX 281152
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
752 AM EDT Tue Sep 28 2021

.SYNOPSIS...
A cold front passes through the area this afternoon and evening,
followed by high pressure. A series of weak cold fronts will move
through Wednesday into Thursday. High pressure will then build in
and remains through the weekend. A frontal system will approach
late Sunday into the beginning of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Forecast is mainly on track and has been updated to capture
latest obs and trends. Light showers can be seen on radar just
west of our area and will move through northeast NJ and the
Lower Hudson Valley over the next hour.

An upper level cut-off low spins over Quebec, as a trough extends
down the east coast. At the surface, it`s associated low pressure
system drags a cold front that is currently analyzed over central
New York. This feature will bring showers and thunderstorms to the
area throughout the day.

Showers and thunderstorms will be possible as early as the morning
hours, as shortwave energy ahead of the front moves through the
area. As daytime heating occurs the area should be able to
destabilize even more, which will allow for another round of
showers and thunderstorms in the afternoon and evening. There is
some uncertainty with how much heating will occur due to cloud
cover from the earlier showers. This will play a big factor in
how today will play out. With dewpoints in the lower 60s at the
surface and 500mb temps around -15C, 750-1000 J/kg of MUCAPE can
be expected by the afternoon. Given the greater instability
later in the day and effective shear values of 25-30 knots,
there is a chance of isolated strong to severe thunderstorms
developing. SPC has outlined the southern half of our area in a
marginal risk. The primary threat will be isolated damaging wind
gusts, but given the cold temperatures aloft, 1 inch hail can
not be completely ruled out. Locally heavy rainfall is possible
in any thunderstorms, but with quick moving storms flash
flooding is not a threat. Storm total rainfall is expected to be
around a quarter of an inch for most, with locally higher
amounts possible.

The whole area should be dry just after midnight tonight. Behind the
cold front, winds will be northwesterly as a dry airmass and high
pressure build in. Dewpoints will drop into the 40s across the area.
The interior should see great conditions for radiational cooling and
temperatures should be able to drop into the mid 40s.

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
Northerly/Northwesterly flow will continue on Wednesday. A cool day
is expected, as temperatures won`t make it out of the 60s for most.
These highs will be a few degrees below normal for late September.

Late in the day a weak cold front swings through the area, as
the aforementioned cut-off low moves further south towards the
New England coast. Although moisture is very limited (PWATs .50
to .75 inches), The cold pool aloft combined with surface
heating may create enough instability for an isolated light
shower or two late Wednesday night.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Models continue in good agreement with a -1 to -2 STD height 500hpa
upper low, and associated deep trough, centered over New England on
Thu, and then slowly retreating northeast through Canadian Maritimes
this weekend. The evolution of this closed upper low and deep NE
troughing is expected to keep Hurricane Sam well out to sea late
this week into weekend. The main impacts for the local area will be
an increasing threat for rough surf and dangerous rip currents late
week into this weekend. Please refer to the National Hurricane
Center for the latest forecasts on Sam.

At the surface, a weak front push through the region Thursday as the
closed upper low slides through northern New England. Cyclonic flow
and pva will bring considerable instability cloud cover and even
potential for isolated shower across northern and eastern areas
Thursday. Thereafter, Canadian high pressure builds into the region
Fri into Sat, lingering into Sunday bringing dry and early fall like
weather. Highs will generally be in the 60s to around 70, with lows
in the 40s and 50s.

As the closed low lifts N/NE of the area this weekend, models coming
into a bit better agreement with development of broad troughing over
the north Central US, with a mid week SW US upper low shearing
towards the region in a flattening upper flow late weekend/early
next week. This will have a frontal system approaching the eastern
US Sunday into early next week, but uncertainty on how much progress
eastward it makes with confluent upper flow and Canadian high
pressure still nosing into the NE US. This system would bring the
next threat for rain early next week, but predictability low at this
time.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
A cold front approaches this morning and moves through the
terminals this afternoon into evening. High pressure builds
towards the region tonight.

VFR, outside of shra/tsra. Isolated showers and tsra this am,
then scattered showers and thunderstorms expected between 16z
and 24z.

SW winds 8 to 12 kt early this morning, veering west through morning
push. W/WNW winds this afternoon, becoming NW this evening with
frontal passage. NW winds 8-12 kt with occasional gusts
to 20 kt tonight.

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

Isolated shra and tsra btwn 13 and 16z. Scattered shra and tsra
and MVFR cigs btwn 16z and 24z. Winds will hover between 300
and 320 mag this afternoon, becoming definitively right of 310
mag during eve push.

.OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
.Wednesday-Thursday...VFR. NW winds. Gusts 15 to 20 kt on Wed.
Isolated showers east of the NYC metro terminals Wednesday night and
Thursday.
.Friday through Saturday...VFR.

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

&&

.MARINE...
A SCA for the ocean waters remains in effect through 2 PM for 5 foot
waves. Waves should fall below SCA criteria after this time.
Occasional northerly wind gusts up to 25 knots are possible late
tonight after the passage of the cold front over the ocean
waters.

Winds are expected to remain below SCA criteria (NW gusts to 20 kt)
with a series of weak cold fronts moving through the waters Wed thru
Thu, and then diminishing further Friday into the weekend as high
pressure building over the waters.

Waves are expected to be sub-sca through the remainder of the week,
but energetic long period swells from Hurricane Sam will begin to
affect the waters Friday and continuing to build into the
weekend.

&&

.HYDROLOGY...
No hydrologic impacts are expected through next Saturday.

&&

.TIDES/COASTAL FLOODING...
For today, despite a developing offshore flow, a high risk of rip
currents is likely with 2-ft long period ESE swells and residual 4-5
ft southerly wind waves.

For Wednesday, an offshore flow continues. Any residual waves
diminish to 2-4 ft and will come out of the northeast, which is not
a favorable direction. However, 1 ft waves with a long period (13
sec) out of the SE are expected, leading to a moderate risk of rip
currents.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Rip Current Risk through this evening for NYZ075-080-081-
     178-179.
NJ...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for ANZ350-
     353-355.

&&

$$
SYNOPSIS...JT/NV
NEAR TERM...JT
SHORT TERM...JT
LONG TERM...NV
AVIATION...NV
MARINE...JT/NV
HYDROLOGY...JT/NV
TIDES/COASTAL FLOODING...JT

NWS OKX Office Area Forecast Discussion