000
FXUS61 KOKX 222003
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
403 PM EDT Tue Aug 22 2023
.SYNOPSIS...
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High pressure will continue to build in from the west through
Wednesday morning, then moves offshore by early evening. A
frontal system will impact the area Thursday into Friday. A weak
cold front will pass through late Saturday, with Canadian high
pressure building in behind it early next week.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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An amplifying upper trough extending southward from the
Canadian Maritimes to along the New England coast will send
another shot of cooler air into the region overnight as lows
drop into the mid 50s inland, around 60 along the coast, and
lower to mid 60s across the NYC/NJ metro. Portions of the Pine
Barrens region of eastern LI may get down to 50 with light
winds/clear skies. This is about 5 degrees below normal.
At the surface, high pressure builds in from the eastern Great
Lakes. Northerly winds pick up a bit the second half of
tonight, especially across eastern LI and SE CT, where the
pressure gradient tightens a some cooler air filters south
across eastern New England.-- End Changed Discussion --
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
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High pressure builds across the area during the morning hours
Wednesday and then offshore in the afternoon as winds veer
around from the NE to S/SE at 5 to 10 mph. Heights aloft build
ever so slightly as the anomalously high amplitude ridge across
the mid section of the country expands a bit east and the
trough across New England lifts out into the western Atlantic.
Highs on Wednesday actually may be a degree or two cooler with
highs mainly in the mid and upper 70s.
Mid and high level clouds associated with warm advection ahead
of low pressure moving out of the Northern Plains and Upper MS
Valley approaches late in the day. Airmass will likely take some
time to moisten with low chances for showers after midnight
Wednesday, mainly north and west of NYC. Lows Wednesday night
may be a touch warmer in spots due to the return southerly flow
and increasing cloud cover.-- End Changed Discussion --
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
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Into late week, a northern stream shortwave rounds a sprawling but
flattening H500 ridge that retrogrades into the Southern Plains.
This will steer a developing frontal system toward and through the
region Thursday and Friday, before high pressure returns once again
this weekend.
As surface low pressure tracks into the Great Lakes, its warm front
stretches east into the Mid-Atlantic, lifting north toward the
region Thursday. This will allow for increasing rain chances through
the day as showers expand in coverage. Highest likelihood of rain
occurs Thu eve into the overnight as the front itself lifts through.
Rain chances remain elevated Friday as the region becomes warm
sectored, with a pre frontal trough helping to force additional
scattered convection ahead of the attendant cold front that moves
through Friday evening.
Exact strength/track of the surface low will be refined, but some
ingredients to work with for heavy downpours during this time
period, in terms of subtle shortwave forcing, moisture convergence
with a modestly strong LLJ developing ahead of low pressure,
interacting with edge of instability gradient to the SW and
subtropical moisture from once Pacific tropical cyclone Hilary
rounding the ridge into the region. Overall, QPF ranges from 0.5 to
1.5 inches, with locally higher amounts possible. CSU MLP and WPC
continue to highlight the region with a marginal risk of excessive
rainfall, which seems fair given the relatively high moisture
content but progressive nature of this system. At this point any
severe threat appears to be limited, with high shear in an elevated
CAPE environment but with a strong 700-900 cap. While the final
outcome will ultimately be contingent on strength/track of surface
wave, the overall pattern appears limiting.
The system pushes south and east on Friday, with the cold front
passing in the afternoon, maintaining chances for showers and a few
thunderstorms through this time. Weak high pressure builds in Fri
night/Sat, before another shortwave and reinforcing cold front
tracks through Sat aft/eve. While this might instigate a few showers
ahead of the fropa, widespread rainfall is unlikely at this point.
Drier conditions await early next week as high pressure tracks south
out of Canada.
Temperatures start off a bit below normal, with highs on Thursday in
the upper 60s to mid 70s, likely the coolest day in about two
months. This nudges up Fri/Sat with most closer to 80, before
another cooldown early next week as Canadian high pressure builds in
and maintains a northerly flow.
Finally, while additional impacts are unlikely, swells from well
offshore Tropical Storm Franklin will likely build early next week,
with increasing potential for high surf and dangerous rip currents.
Monitor https:/www.weather.gov/okx/tropical for the latest NHC
forecasts on this tropical system and others.-- End Changed Discussion --
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
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VFR. High pressure remains in control through Wednesday.
NNE-NE winds 10-15kt into early this evening. An occasional gust to
20 kt possible through 21z for Long Island and southeast Connecticut
terminals. Sustained winds begin to weaken this evening and the
direction may briefly veer towards the ENE-E for coastal terminals
towards sunset (KISP, KBDR, and KGON). Winds go back to the NNE
overnight and will remain light. NNE-NE winds under 10 kt Wednesday
morning will become S Wednesday afternoon.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Winds at KJFK could briefly shift towards the ENE-E around 00z.
Timing of wind shift to the S on Wednesday may be off by 1-3 hours.
OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
Wednesday Afternoon-Night: VFR.
Thursday: Chance of showers with MVFR possible. S-SE gusts 20-25 kt
possible in the afternoon.
Thursday Night-Friday: MVFR or lower possible. Showers with possible
thunderstorms, especially Thursday night into early Friday
afternoon. S gusts 20-25 kt into Friday morning.
Saturday: Mainly VFR, Slight chance of a shower.
Sunday: 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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Sub-SCA conditions through Wednesday as high pressure builds
across the waters.
Strengthening SE-S flow ahead of an approaching frontal system late
Thursday through Friday will likely develop 25 to 30 kt gusts on the
ocean and possibly all waters. Ocean seas should quickly respond to
5-7 ft during this time in response, and may remain elevated at SCA
levels into early Saturday.
Thereafter, sub SCA conditions expected for the weekend on all
waters, with a weak cold frontal passage late Sat/Sat night,
followed by building Canadian high pressure.-- End Changed Discussion --
&&
.HYDROLOGY...
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A frontal system will bring potential for a period of downpours and
embedded thunderstorms Thu into Fri. WPC outlined the region in a
marginal risk of excessive rainfall, indicating localized flash
flooding is possible. Overall, QPF from this event ranges between
0.5 and 1.5 inches.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
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A low rip current risk continues for all Atlantic-facing beaches
Wednesday with surf height under 2 ft.
A moderate risk of rip current development is in place for all
beaches Thursday, though the risk increases through the day and may
be become high by day`s end as 5+ ft southerly wind waves develop.
Swells from tropical cyclone Franklin will likely build early next
week, with increasing potential for high surf and dangerous rip
currents.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DR/DW
NEAR TERM...DW
SHORT TERM...DW
LONG TERM...DR
AVIATION...DS
MARINE...DR/DW
HYDROLOGY...DR/DW
TIDES/COASTAL FLOODING...//