-- Discussion containing changed information from previous version are highlighted. --
766
FXUS61 KOKX 241139
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
739 AM EDT Tue Sep 24 2024

.SYNOPSIS...
High pressure over the Canadian Maritimes and the Northeast
will remain anchored for one more day before gradually giving
way to an approaching frontal system on Wednesday. The front
moves across the area Thursday into Thursday night. High
pressure builds to the north Friday and then remains into the
beginning of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Upper level ridging gets another boost across the region today
ahead of an amplifying upper trough over the mid and upper MS
Valley. This will keep the surface high over eastern Canada
anchored for another day. There should be mix of sun and clouds
with the best chance to see sun today across CT and LI. It`s a
bit tricky with moisture being advected on an easterly flow
beneath an inversion at 85h.

Highs today are forecast to top out in the upper 60s to around
70.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
There is generally good overall agreement in the guidance with
some small timing issues. Upper ridge axis across the area
begins to translate east as an upper trough approaches form the
Mississippi Valley. The latter of which closes off an upper low
over the Mid MS and TN Valleys Wednesday into Thursday. However,
the northern part of the trough axis slides east across the
Great Lakes and Northeast, sending a frontal system across the
area on Thursday. The better dynamics and lift pass to the north
and west of the area along with the heavier rainfall. Areas to
the north and west of NYC may see amounts up to quarter inch or
perhaps a bit higher. The dry air and ridging hanging on just
off the east coast will take time to overcome and rainfall
amounts from NYC and points east may be as low as tenth of an
inch or less. This is a trend downward from the previous
forecast. Most of the shower activity will br driven by weak
thermal forcing late Wednesday into Thursday. Have also removed
thunderstorms as well due to 85-50h lapse rates generally less
than 5C and CAPE values less than 500 J/kG. NAM is a bit more
unstable, but not buying into at this time.

Expect plenty of clouds tonight into Thursday with temperatures
and humidity gradually on the rise Wednesday night into
Thursday. Highs Wednesday will be in the 60s, then up into the
70s Thursday as a warm front lifts through and SE winds become
SW. Lows by Thursday morning will be upper 50s inland to the
lower 60s at the coast, warmest across the NYC metro. These
values are about 5 degrees above normal.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Key Point:

* An extended period of dry weather is expected for much of the long
  term period, from Friday through the beginning of next week.

As a departing trough pushes off to the east and the circulation
originating from the tropics becomes intertwined in an upper level
low over the Southeast US, a strengthening ridge builds over much of
the Northeast for the weekend. This mid-level ridging is likely to
be accompanied by a strong surface high pressure system dropping out
of Canada that will act as a shield over the Northeast US allowing
for mostly dry conditions. There has been some model trends recently
that may result in some shower activity approaching parts of the the
southwestern portions of the area as a large cut-off low pressure
system spins over the Southeast US, but confidence in shower
activity is low. As a result, kept PoPs capped at slight chance for
the extreme southwest portions of the area through much of the
extended period. It will not be until the cut-off low becomes
reintroduced to the large-scale flow sometime Tuesday-Wednesday that
the area will see the next decent chance of showers.

Temperatures during the long term will be around average with highs
each day in the upper 60s to middle 70s. Lows each night will be
generally in the 50s.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
High pressure remains in control through today.

Mainly VFR expected today though an area of low stratus is
resulting in localized MVFR conditions for some city terminals
this morning, mainly KEWR and KLGA. This is expected to scatter
out before 15Z. More widespread MVFR ceilings are expected to
move into most terminals after 00-03Z Wednesday.

Widely scattered SHRA may approach the terminals from the west
on Wednesday morning but confidence is too low to include in the
TAFs at this time.

E-NE winds around 10 kt during the day shifting more E in the
afternoon. An occasional gust of 15 to 20 kt is possible during
the late morning into the early evening hours.


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

Unscheduled amendments possible for changing flight categories
due to marginal MVFR cigs.

OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...

Wednesday: Chance of showers with MVFR or lower cond from the NYC
metros north/west, otherwise VFR.

Wednesday night: Chance of showers with MVFR or lower cond
throughout, but mainly after midnight at KISP/KGON. Slight chance of
a tstm in the evening from the NYC metros north/west.

Thursday: Chance of mainly morning showers/MVFR cond, otherwise VFR.

Friday and Saturday: VFR.

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

&&

.MARINE...
Elevated long period easterly swells from a slow departing
offshore low pressure will to continue to produce SCA seas into
Wednesday. Confidence beyond that time is not sufficient to
extend farther out in time, but a definite possibility.

Waves on the ocean may remain near 5 feet early Thursday night but
fall below SCA thresholds by early Friday morning behind a weak
frontal system. Sub-SCA conditions are then expected through
the weekend for all waters.

&&

.HYDROLOGY...
There are no hydrologic concerns through this weekend.

&&

.TIDES/COASTAL FLOODING...
Water levels continue to slowly recede as high tides lower.
However, easterly swells have made it difficult for back bay
locations of western LI to drain. Additional brief minor coastal
flooding is possible at the most vulnerable locations in the
south shore back bays this afternoon, particularly in southern
Nassau and SW Suffolk. Plan to stay closer to Steven`s guidance
for this reason, which is higher. No additional issues are
anticipated beyond that time.

The high risk of rip currents continues through Wednesday
evening with offshore low pressure still producing long period
E/SE swells across the waters.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Risk for Rip Currents through Wednesday afternoon for NYZ075-
     080-081-178-179.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT Wednesday for ANZ350-353-
     355.

&&

$$

SYNOPSIS...DW/MW
NEAR TERM...DW
SHORT TERM...DW
LONG TERM...MW
AVIATION...MW
MARINE...DW/MW
HYDROLOGY...DW/MW
TIDES/COASTAL FLOODING...