Area Forecast Discussion
Issued by NWS Upton, NY

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026
FXUS61 KOKX 202008
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
408 PM EDT Fri Sep 20 2024

.SYNOPSIS...
Low pressure will remain south and east of Long Island through
Saturday, then head slowly farther out to sea into early next
week. Meanwhile, high pressure will nose in from the northeast
this weekend and remain in control through at least early
Tuesday. A frontal system may then approach and move through
during mid to late week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Showers have drifted westward into part of the forks of Long
Island and far SE CT as expected. These are already starting to
retreat very slowly back to the east, but expect another chance
for showers out east tonight especially after midnight as a mid
level vort max pinwheels around the upper low centered just SE
of New England. This should also bring mostly cloudy skies to
areas to the west, but those area should also remain dry.

As weak CAA begins on N-NW flow, low temps tonight should range
from the lower 60s in the metro area and along the coast, to
the mid 50s well inland.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Cooler conditions expected on Sat as nigh pressure noses down
from the NE, with wind gusts 20-25 mph mainly from NYC east, and
continued chance of showers across far ern sections. Interaction
with the upper low and weak troughing approaching from the Great
Lakes will likely increase overall cloud cover a bit, through
there could be more in the way of afternoon sunshine across
western sections. High temps will be in the 70s in most places,
but remain on the upper 60s across some far ern sections of
Long Island and CT.

Continued CAA n a N-NE flow will lead to low temps in the 50s
throughout.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Key Points:

* Dry into much of Tuesday.

* Possible showers mid to late week with an approaching frontal
  system.

* Temperatures will likely end up slightly below normal starting
  Monday.

Offshore low pressure continues to departure on Sunday as high
pressure centered well to our northeast noses into the area.
Aloft, heights start to rise, especially the second half of
Sunday, as an upper level ridge builds in. This pattern will
lead to dry and mostly sunny conditions Sunday and Monday. With
low pressure heading away from the area, the pressure gradient
will lower and allow winds to gradually decrease. Used the NBM
10th percentile for low temperatures Sunday night across
northern portions of the interior as winds will be lightest and
there will likely be less cloud coverage. Otherwise, followed
the NBM closely for Sunday and Monday.

There is some disagreement for what happens mid to late week
with the approach and passing of a frontal system. Any
unsettled weather from this system will depend on strength of
surface high pressure and evolution of the approaching upper
level trough. Went slightly lower than NBM with PoPs based on
the latest GFS keeping the surface high locked in over the
northeast. Otherwise, stuck close to the NBM. With the
wetter/cloudier solution temperatures will likely be just below
normal much of the week. If guidance starts trending closer to
the latest GFS, a drier/more sun solution may end up with
slightly warmer temperatures.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
Low pressure will remain south and east of Long Island through
Saturday.

Mainly VFR but some MVFR stratus this evening, mainly eastern
terminals. VCSH out toward KGON where some low level moisture
may spiral in off the ocean from the north east. However, rain
shield has been struggling to move farther west. There may be
more low stratus late tonight and early Saturday as additional
moisture briefly increases off the Atlantic, otherwise Saturday
will be mainly VFR with pockets of MVFR once again.

NE winds 10-15 kt with gusts near 20 kt this afternoon will
diminish to 5-10 kt flow on average tonight. NE winds 10-15 kt
with gusts near 20 kt possible Saturday.

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

Amendments possible for any potential MVFR ceilings.

OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY...

Saturday: VFR. MVFR in possible showers, but low chance of
occurring, mainly near KGON. NE winds G15-20kt possible, highest
east.

Sunday: VFR. NE winds G15-20 kt possible, highest east.

Monday: VFR.

Tuesday and Wednesday: Mainly VFR, with pockets of MVFR
possible.

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

&&

.MARINE...
SCA has been extended into daytime Sunday for the ocean waters,
and into daytime Sat for the far ern Sound and
Peconic/Gardiners Bays. Winds there should gust to 25-30 kt,
highest on the ern ocean waters, with ocean seas on the outer
waters building from 6-7 ft to 8-10 ft by daytime Sat.
Ocean seas should subside somewhat Sat night back to 6-7 ft.

With the exception of the far eastern ocean waters, wind gusts
will likely be below 25 kt on Sunday. Ocean seas will however
remain elevated through at least the middle of the week, and
extensions to the current SCA are likely.

&&

.HYDROLOGY...
There are no hydrologic issues through the middle of next week.

&&

.TIDES/COASTAL FLOODING...
Coastal flooding should continue into and early next week due
to offshore low pressure and an associated persistent E wind
fetch, with elevated ocean seas. Surge increases into tonight
and then may not change much into Saturday. While astronomical
levels will be on a downward trend, the surge will compensate
for the total water level.

Forecast surge varies from near 1 to near 2 ft, highest along
the south shore bays of Long Island and parts of western Long
Island Sound. These areas plus parts of lower NY Harbor should
see the greatest impact.

Minor to moderate coastal flooding expected through Saturday.
Coastal flood watches are in effect for the Saturday high tide
cycle for for the south shore bays of Nassau/Queens, most areas
along the westernmost Sound and the SW CT coastline, and along
lower NY Harbor.

The high rip current risk through Saturday will likely need to
be extended into Sunday.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Coastal Flood Advisory from 11 PM this evening to 4 AM EDT
     Saturday for CTZ009-010.
     Coastal Flood Watch Saturday afternoon for CTZ009-010.
NY...Coastal Flood Advisory from 11 PM this evening to 4 AM EDT
     Saturday for NYZ071-073-078-176-177.
     Coastal Flood Watch Saturday afternoon for NYZ071-073-177.
     Coastal Flood Advisory from 8 PM this evening to 2 AM EDT
     Saturday for NYZ072-074-075-080-081-178-179.
     Coastal Flood Watch from Saturday morning through Saturday
     afternoon for NYZ074-075-080-178-179.
     High Risk for Rip Currents through Saturday evening for NYZ075-080-
     081-178-179.
NJ...Coastal Flood Advisory from 8 PM this evening to 2 AM EDT
     Saturday for NJZ006-106-108.
MARINE...Small Craft Advisory until 6 PM EDT Saturday for ANZ332.
     Small Craft Advisory until noon EDT Saturday for ANZ340.
     Small Craft Advisory until 6 PM EDT Sunday for ANZ350-353-355.

&&

$$

SYNOPSIS...BG/JT
NEAR TERM...BG
SHORT TERM...BG
LONG TERM...JT
AVIATION...IRD
MARINE...BG/JT
HYDROLOGY...BG/JT
TIDES/COASTAL FLOODING...DW