000
FXUS61 KOKX 232004
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
404 PM EDT Sat Sep 23 2023
.SYNOPSIS...
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The region will be in between high pressure in the Northern Atlantic
and Tropical Storm Ophelia well to the south and west tonight.
Ophelia is forecasted by the National Hurricane Center to transition
from tropical storm to a post-tropical depression tonight into
Sunday morning as it moves northward within the mid-Atlantic.
Meanwhile, an associated warm front will approach the region tonight
and stall south of Long Island this weekend.
The area of low pressure will continue to approach to close this
weekend before passing south of Long Island early next week. This
will be followed by high pressure building in from Southeast Canada
mid into late next week.
For the latest forecasts on Tropical Storm Ophelia, refer to the
National Hurricane Center at www.nhc.noaa.gov and/or the NWS New
York office`s tropical page at weather.gov/okx/tropical-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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Tropical Storm Ophelia made landfall in North Carolina early today
and has been weakening over land as it slowly track northward.
Precip along a warm front from Ophelia has been steadily falling
across the region with mostly light rainfall rates. This is expected
to continue into tonight, though it may be more intermittent at
times as most guidance gives a break tonight into early
tomorrow.
Winds may still gust around 30 mph for southern areas for the
evening with winds letting up overnight with peak gusts around 25
mph.
With gusty winds, persistent cloud cover, and occasional rain,
temperatures tonight will remain in the low 60s for southern
portions of the CWA with northern portions of the CWA seeing
mid/upper-50s tonight.
Instability looks very low with many models, but a few such as the
NAM does hint as slightly higher levels of elevated instability
overnight. I`ve included the chance for isolated thunder in the
forecast for this chance, but I emphasize it will likely remain
isolated.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
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High moisture and lift associated with Ophelia and its warm front
will persist on Sunday as Ophelia transitions into a post-tropical
depression. Precip will likely be on-and-off through the day with
mostly light to moderate rain expected. Some areas of heavier
embedded rain is possible associated with the slow-moving Ophelia as
it nears, enhanced by the nearby warm front just offshore to the
south. WPC has a portion of the area under a slight risk for the
risk of heavier rainfall leading to localized flood issues. HREF
neighborhood probabilities of exceeding 0.5"/HR are around 30% in
some areas. Total rainfall for tonight and tomorrow is forecast
between 1.5-2.25" with the highest totals in NE NJ, W LI and NYC
metro. HAFS and REG GEM differ from most models and have Ophelia
moving a little quicker which would place more precip over CT, but
confidence in this scenario is much lower.
Winds will remain from the east to north east on Sunday gusting up
to 25 mph, with the best chances for this for areas to the south.
Temperatures will continue to be cool, but warmer than Saturday,
with highs in the mid/low-60s. More breaks in the rain earlier in
the day will likely allow for these temperatures to be warmer than
Saturday before coverage has the chance to increase again later in
the day.-- End Changed Discussion --
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
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Much of the guidance has come into good agreement with a band of
moderate to heavy rain to the north and west of the remnant low
track, which passes to the south Monday morning. This appears to be
due to enhanced baroclinicity to the north of the low. Models have
been going back and forth with this scenario the past week, but the
12Z guidance is strongly supporting this solution. The rain will
gradually shift to the south and east during the day with most
locations expected to dry out from north to south in the afternoon.
Stayed above NBM PoPs in this instance which seemed low based on the
latest trends.
Thereafter, a large dome of high pressure over eastern Canada
settles south through the week, building across the Northeast and
Mid Atlantic states. Also, during this time the area will be under a
prolonged period of NE/E flow. A gusty NE flow Monday, 20 to 30 mph,
strongest at the coast, will gradually diminish Monday night into
Tuesday. Once past Monday night, there should be a fair amount of
sun during the period. The one caveat to watch is with the easterly
flow perhaps some cloud cover lingering near the coast.
Temperatures during this period will generally be several degrees
below normal, with high in the 60s and lows in the 40s and 50s. The
coolest day will be Monday with highs in the lower to mid 60s,
warming to around 70 at weeks end.-- End Changed Discussion --
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
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Tropical Storm Ophelia, moving into southeastern Virginia at 19Z,
will track northward and gradually turn northeast by Sunday morning
as Ophelia reaches the Delmarva. Rain/showers will continue, with
breaks possible later this evening and into tonight. Widespread MVFR
with areas of IFR will persist through the forecast period. There is
uncertainty as to where and when IFR conditions will occur.
Winds remain from the NE to ENE through the forecast, with the
highest sustained winds and gusts near the coast. Winds will be more
ENE toward Sunday morning and through 18Z.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of any flight category changes is uncertain, with MVFR and
IFR. IFR is possible at KLGA and KJFK tonight, while KEWR and KTEB
remain at IFR. LIFR is not expected, but brief LIFR is possible
overnight.
OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...
Sunday: MVFR to IFR with showers. NE to ENE winds around 15kt
gusting 20-30kt early in the morning, and 20-25kt late morning
through the afternoon.
Monday: Mainly VFR. MVFR possible in showers, ending from nor south
to south through the afternoon.
Tuesday through Thursday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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For Sunday, wind gusts mostly in the SCA range which will
gradually lower below SCA thresholds Sunday night across the
forecast waters. Ocean seas remain well into SCA range Sunday
through Sunday night. For early Sunday, there could be some
remaining localized areas with gale force gusts.
Low pressure passing to the south of the waters on Monday and
building high pressure to the north could produce a period of gale
force gusts, especially on the ocean waters, through Monday evening.
Thereafter, winds and seas will gradually diminish, building to 7 to
10 ft by Monday evening, then slowly subsiding to around 5 ft by
Wednesday.-- End Changed Discussion --
&&
.HYDROLOGY...
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Storm total rainfall of near 1.5 to 2.25 inches forecast for
much of the region tonight through Monday. Maximum hourly rates
still appear to be mainly around a quarter to half inch but
could get higher Sunday with some convective showers. There
remains an isolated risk for flash flooding this weekend
especially for any locations that get locally more than a few
inches and if those locations are poor drainage and low-lying.
For Tuesday through next weekend, expecting a dry forecast.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
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There is a high rip current risk for all Atlantic facing beaches
through Sunday early evening due to long period easterly wind
waves and E/S swells.
A high surf advisory is in place for all coastal zones of Long
Island, including the ocean shorelines of Brooklyn and Queens
through early Sunday evening. Breaking waves of 6 to 10 ft are
forecast from a combo of E/S long period swells. This will lead
to beach flooding and erosion, with scattered areas of dune
erosion. The threat for localized overwashes is low at this
point. Surf will subside to 4 to 8 Sunday afternoon, but could
continue at that level into early next week with onshore flow.
Strengthening E/NE flow ahead of an approaching warm front will allow
for surge of around 1 ft to develop for the aft/eve high tide,
resulting in minor coastal flooding along the Lower NY/NJ
Harbor, Jamaica Bay, Great South Bay of Nassau County, as well
as coastal Westchester and Fairfield counties. Elsewhere across
LI and NYC, generally localized minor coastal flooding expected
due to combo of wave action and elevated water levels.
Another round of localized minor coastal flooding is likely for
Lower NY/NJ harbor and southern bays of NYC/LI on Sunday with a
persistent but weakened onshore flow. Additional rounds of minor
coastal flooding are possible for next week as astronomical tides
continue to increase, and E/NE flow possibly strengthening depending
on evolution of TS Ophelia.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Coastal Flood Advisory until 8 PM EDT this evening for CTZ009.
NY...Coastal Flood Advisory until 8 PM EDT this evening for NYZ071.
High Risk for Rip Currents through Sunday evening for NYZ075-080-
081-178-179.
High Surf Advisory until 8 PM EDT Sunday for NYZ075-080-081-
178-179.
Coastal Flood Advisory until 5 PM EDT this afternoon for
NYZ178-179.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT Monday for ANZ331-332-335-
338-340-345.
Gale Warning until 6 AM EDT Sunday for ANZ350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...BR/DW
NEAR TERM...BR
SHORT TERM...BR
LONG TERM...DW
AVIATION...MET
MARINE...BR/DW
HYDROLOGY...BR/DW
TIDES/COASTAL FLOODING...