000
FXUS61 KOKX 271801
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
201 PM EDT Sun Aug 27 2023
.SYNOPSIS...
High pressure builds in from the north and west today and slides
offshore Monday afternoon. A stationary front northwest of Tropical
Cyclone Franklin, which will stay well south and east of the area,
briefly backups toward the east coast Monday and into Tuesday. A
cold front moves through early on Wednesday, followed by high
pressure building in Thursday and settling nearby on Friday. High
pressure should remain in control to start next weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
Forecast remains on track with only minor adjustments to
reflect the current observations and conditions.
High pressure builds in from the north and west today as a shortwave
trough moves through aloft. The flow aloft then becomes zonal
briefly tonight as the shortwave lifts out of our area.
The synoptic flow, given the orientation of the high, will be
generally northerly and cooler, drier air will filter into the area.
Offshore, a weak wave of low pressure will move along a stalled
frontal boundary and pass well to our southeast. The surface flow
over far eastern locations may become a bit more easterly. This
would create some surface convergence over eastern locations and the
CAMs are firing up some showers this afternoon in association with
this forcing. These areas are also more unstable, with forecast
soundings showing about 1000 J/KG of uncapped SBCAPE. Have went
ahead and added in chances of afternoon showers. An isolated
thunderstorm can also not be ruled out, but confidence is too low to
include in the forecast at this time.
Highs today and lows tonight will both be right around normal for
late August, mid 70s to low 80s and upper 50s to upper 60s.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
The upper level trough becomes more pronounced again early
Monday. By Monday afternoon, the aforementioned surface high
will slide offshore to our north and east. Off to our south, a
stationary front well north and west of Tropical Cyclone
Franklin will start to edge north and west as a warm front
Monday night into Tuesday. Around the same time frame, Tropical
Cyclone Franklin is expected to lift north in the Western
Atlantic. The system is progged to stay well offshore with no
direct impacts. However, some indirect impacts will be dangerous
rip currents due to an increasing swell and high surf. Later on
Tuesday a shortwave trough and surface cold front approach and
will ultimately aid in pushing the Tropical Cyclone east.
There continues to be uncertainty with the extent of the rain shield
Monday into Tuesday as the front interacts with mid-latitude jet
energy as an upper trough amplifies across the Great Lakes. The 00z
run of the NAM is the most aggressive and shows a frontal wave
moving right over the area with heavy rain early Tuesday. Have not
bought into this solution yet, but trends in guidance will have to
be watched. Currently have chance PoPs Monday night through the rest
of the short term period.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
During Tue night some shortwave energy is progged to push through
early, followed by a cold front which should start to push through
early Wed morning. Around the same time frame Tropical Cyclone
Franklin is expected to lift north in the Western Atlantic and pass
well east of the area during the day Wed as the system is progged to
stay offshore with no direct impacts. However, some indirect impacts
will be dangerous rip currents due to an increasing swell and high
surf, especially out east with regard to the surf. With an onshore
flow it appears that instability will be fairly minimal, especially
at the sfc Tue night. With some elevated instability pushing through
from the west and southwest have included slight chance / isolated
thunder. The cold front associated with the upper trough begins to
pivot through into early Wed AM. Did maintain some continuity with
the cold frontal passage with shower chances and slight chance
/ isolated thunder through Wed AM, especially for the eastern half
of the area. Chance for precip then become quite minimal into later
in the day Wed, as drier air mass attempts to nudge in.
Behind the frontal boundary look for a cP air mass with cooler
temperatures and comfortable conditions into the later half of the
week. Temperatures will be near normal with leftover humidity on
Wed, followed by cooler temperatures and noticeably lower humidity
with dew point readings in the 50s by late Wed night into Thursday.
High pressure will be in control with dry conditions likely Thursday
and Friday. Another system of tropical origins should pass to our
south and off the Carolinas, or as far north as the VA Capes
depending on the guidance being used late in the week. The northern
edge of the cloud canopy from this system may lead to more clouds
than sun on Friday but all indications for now is it stays dry this
far north. After slightly below normal temps on Thu, seasonable
temperatures are anticipated for Fri and Sat.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
High pressure from the Great Lakes region gradually builds across
and north of the area through the TAF period.
VFR through this evening, with sub VFR conditions towards 08-09z
Monday. There is still a chance of some showers late this
afternoon and early this evening for KGON terminal.
Winds predominantly N-NE continues through early this
afternoon. Then winds shift to an easterly direction as the
high pressure begins to drift offshore. Coastal terminals
should get a sea breeze around 20Z this afternoon. Winds then
become light overnight and become more onshore allowing for low
stratus to move in off the ocean with MVFR to possibly IFR
conditions. Sub VFR conditions likely persist through early
Monday morning, improving to low VFR conditions by afternoon.
Winds will generally be out of the east at around 10 kts on
Monday.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments possible, mainly for wind direction changes and timing of
sea breeze this afternoon / early this evening.
OUTLOOK FOR 18Z MONDAY THROUGH THURSDAY...
Monday: MVFR in AM, then mainly VFR.
Tuesday: MVFR or lower in SHRA, especially in the afternoon and
evening.
Wednesday: MVFR possible early in shra or tsra, otherwise mainly VFR.
Thursday and Friday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Sub-SCA conditions are expected through Tuesday as high
pressure builds in and then slides offshore.
An increasing SE / S swell into Tuesday night and through the day
Wed will lead to small craft conditions on the ocean as seas climb
to 5 to 6 ft for much of the ocean waters. Further east out on the
ocean 7 to 8 ft seas are more of a likelihood Wed and Wed night.
Also by Wed night small craft gusts to 25 kt out on the ocean will
be more likely. Also during this time period, rather energetic S to
SE swells will peak at 13 to 14 seconds. Seas are then expected to
come down gradually Thu and Thu night with a long period SE swell
lingering.
&&
.HYDROLOGY...
There are no hydrologic issues through next week at this time.
&&
.TIDES/COASTAL FLOODING...
There is a moderate risk for rip current development for all the
beaches today and Monday with a 2-3 ft ESE swell. On Monday, an
easterly wind at 10-15kt will add a favorable longshore current to
the rip threat.
Swells from Tropical cyclone Franklin begin to build late Monday
into Tuesday, then continuing and peaking into midweek with 13 to 14
second long period swells for Wed and Wed night. In addition, a full
moon Wed night will have astro tides increasing through the mid to
late week period. Thus, chances have increased for high surf and
dangerous rip currents through early Thursday. Combined with the
high surf, the potential exists for areas of ocean beach
erosion/flooding and for scattered areas of dune erosion during the
times of high tide Tue/Wed. With respect to coastal flooding, minor
coastal flood benchmarks may be approached for some locations in the
western south shore bays for the Mon night high tide cycle. More
locations like western LI Sound gauges in CT and perhaps Staten
Island may approach minor benchmarks Tue night, with some gauges in
the western LI south shore bays potentially exceeding minor
benchmarks for Tue night. This potential will likely linger into the
Wed night high tide cycle as well. In subsequent forecast releases
coastal flood statements, and coastal flood advisories may be
needed, especially for the western south shore bays.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$