000
FXUS61 KOKX 231611
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1211 PM EDT Wed Aug 23 2023
.SYNOPSIS...
-- Changed Discussion --
High pressure will begin to slide east late this afternoon and
tonight. Low pressure moving out of the Great Lakes region will
then send a warm front slowly toward the area Thursday into
Thursday night, lifting into and through the area Friday into
Friday night. A weak cold front will pass through late Saturday,
with Canadian high pressure building to the north and then east
behind it early next week. A slow moving frontal system will
approach for Tuesday and Wednesday.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Forecast largely on track this afternoon with high pressure
over the area beginning to move offshore late this afternoon and
evening. Temps should reach 80 in NE NJ, with mid/upper 70s
elsewhere, a couple degrees below latest NAM/GFS MOS numbers as
was the case with temps yesterday.
A shortwave impulse diving toward the area in NW flow aloft
between the large heat ridge over the central states and the
upper trough over eastern Canada should start increasing
moisture tonight. Low levels still look dry and have kept PoPs
out of forecast except for Orange and W Passaic until well after
midnight.
Lows tonight with light return flow should still manage to fall
to 55-60 inland, with 60-65 invof NYC.-- End Changed Discussion --
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
Have fcst likely PoP from NYC north/west mainly in the morning
with the warm front not too far off to the west and another
mid level shortwave impulse moving across, but amts should be
on the light side until late Thu night as the front starts to
enter the area. A wave of low pressure likely to develop along
the front with its location uncertain, as 00Z global models and
the 03Z SREF favor the wave to be across upstate NY while the
00Z NAM-12km forecasts it to be close to our forecast area.
Likely/categorical PoP fcst for late Thu night into Fri morning,
with showers and a few tstms. A strengthening 30-35 kt
southerly LLJ along with mid level moisture transport aloft from
the NW will help increase PW to over 2 inches late Thu night
into Fri AM, with a very deep warm cloud layer of 13 kft
present, increasing the risk of heavy downpours. If the NAM is
correct the heavy rain and also svr threat will be enhanced,
with a few rotating storms capable of producing very heavy rain
and strong winds possible.
Most of the forcing should lift to the NE by Fri afternoon as
the warm front lifts through, with PoP lowering to chance for
the afternoon. Fri afternoon will be warm and muggy, with high
temps in the 70s to lower 80s, and dewpoints in the upper
60s/lower 70s.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Persistent mean NE troughing will continue this weekend into
early next week with a series of weak shortwaves tracking
through the region. Meanwhile, the anomalously strong Central
and Southern US subtropical ridge will gradually weaken and
retrograde to the SW.
The first shortwave, associated with a closed low currently over
the PAC NW, will track around the northern periphery of the
Central US subtropical ridge late week and dig through the Great
Lakes into NE US Fri night into Sat. At the surface, this will
have a broad surface wave/cold front pushing through the region
Friday night with associated shower/embedded tstm activity
sliding offshore. High pressure briefly builds in Sat with
seasonable temps.
The upper trough axis continues to dig into the region Sat, with
a Canadian cold front approaching late Sat and likely crossing
Sat night. Moisture and instability will be limited, but
isolated shower and slight chance of thunder possible based on
shortwave forcing/frontal boundary.
Model spread exists on the orientation/strength and
progressiveness of the trough axis and associated closed over
New England for the weekend, having to do with phasing
differences of Pacific shortwaves and northern stream
shortwave. General scenario is for Canadian high pressure to
build in for Sunday and Monday, but a slower progression of the
trough may allow for diurnal instability showers Sunday aft.
Temps will running a few degrees below seasonable for late
August Sunday into Monday.
General consensus in the next in a series of shortwaves digging
into the upper Mississippi River Valley and Great Lakes Monday
night into Tuesday, with a stationary frontal boundary to the
W/SW sliding towards the region Tue/Wed. This pattern and model
consensus points to TC Franklin staying well offshore, but will
have to watch for potential enhancement of downpour activity
along the front Tue/Wed depending on timing/track of Franklin
and trough axis/front. Monitor
https:/www.weather.gov/okx/tropical for the latest NHC forecasts
on this tropical system and others. In terms of indirect
impacts, swells from tropical cyclone Franklin will likely build
late Monday into Tuesday and continue into mid week, bringing
increasing potential for dangerous rip currents and high surf.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
High pressure builds in today and slides offshore Tonight. A
warm front approaches on Thursday.
VFR.
NNE-NE winds under 10 kt for morning push, giving way to SE/S
sea breeze this afternoon into early evening. Winds become
generally light south this evening/tonight.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of wind shift to the S/SE may be off by 1-2 hours.
OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
Late Tonight: VFR. Light S flow.
Thursday: Showers with MVFR development likely for western
terminals, particularly in the afternoon. S-SE gusts 20-25 kt
likely developing in the afternoon.
Thursday Night-Friday: MVFR or lower likely. Showers with
possible thunderstorms, especially Thursday night into early
Friday afternoon. S/SE gusts 20-25 kt into Friday morning.
Saturday: VFR, outside of chance of showers.
Sunday: VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
-- Changed Discussion --
Conditions will remain below SCA levels through Thursday
morning. 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 the bays and ern
Sound. Ocean seas should quickly respond to 5-7 ft during this
time, response, and may remain elevated at SCA levels into Fri
night and possibly early Sat out east.
Thereafter, sub SCA conditions expected for the weekend on all
waters (although ocean seas may run 3-4 ft in long period SE
swell), with a weak pressure gradient regime.
Long period SE swells likely build in from tropical cyclone
Franklin late Monday into Tuesday, likely bringing a return of
SCA conditions on the ocean.-- End Changed Discussion --
&&
.HYDROLOGY...
A frontal system will bring potential for a period of downpours and
embedded thunderstorms Thursday night into Fri. WPC outlined
portions of the region in a marginal risk of excessive
rainfall, indicating localized flash flooding is possible. Areal
avg QPF from this event ranges from 1/2 to 1 inch, but with
potential for downpours of at least 1-2 inches.
&&
.TIDES/COASTAL FLOODING...
A low rip current risk continues for all Atlantic-facing beaches
today with a combo of 2 ft E wind wave and 1 ft SE swell.
The risk of rip current development likely increases from low to
moderate for all beaches on Thursday, with strengthening SE/S winds
and building southerly wind waves. Rip current risk could
potentially increase to high at the beaches of NYC and western
Long Island late aft/early eve as winds increase towards SCA.
A high rip current risk is likely Thursday night into Friday
with 5 ft+ southerly wind waves, possibly lingering into
Saturday.
Swells from tropical cyclone Franklin will likely build early
next week, with increasing potential for high surf and
dangerous rip currents.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BG/NV
NEAR TERM...BG/DS
SHORT TERM...BG
LONG TERM...NV
AVIATION...NV/DW
MARINE...BG/NV
HYDROLOGY...BG/NV
TIDES/COASTAL FLOODING...