000
FXUS61 KOKX 101426 CCA
AFDOKX
Area Forecast Discussion...CORRECTED
National Weather Service New York NY
1026 AM EDT Sun Sep 10 2023
.SYNOPSIS...
A frontal boundary lingers to the north and west today, passing
to the east late Monday. Another cold front passes through the
area on Wednesday, followed by high pressure building for the
second half of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
The first batch of moderate to locally heavy showers, with
embedded isolated thunder, is starting to make its way through
the area from the southwest. The CAMs have really been
struggling with this feature and have been firing up afternoon
convection after showing a mostly dry morning. Given the
coverage of the current showers and the stalled front out of the
area to the north and west, confidence has lowered slightly in
afternoon convection.
A flattening trough axis remains just to the west of the region
today, with a meandering frontal boundary to the north and west
helping to instigate convection once again, aided by additional
shortwave energy moving through in the flow. Heights aloft do
begin to fall slightly as another upper trough digs across
central Canada and the Great Lakes, nudging the weakening trough
and surface boundary eastward.
Conditions will remain humid as temperatures top out in the upper
70s to lower 80s this afternoon. Any showers/thunderstorms
today, given the moisture laden air mass, could produce locally
heavy downpours that may train and could lead to isolated flooding.
WPC has expanded the slight risk to now include the majority of
our forecast area. See hydrology section for more details.
Instability is a bit lower than Saturday, so less of a severe
thunderstorm threat, but still possible a few strong or even an
isolated severe storm pops up. SPC has maintained a general
thunder outlook for the region.
What`s left of the upper trough shears off to the northeast
tonight. Should see the convection weaken and diminish in
coverage tonight with loss of heating but rain chances continue
as the boundary works east. Lows forecast will still be very
mild in the upper 60s to lower 70s with dewpoints in the same
range. Fog will be possible once again.
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
Heights begin to rise a bit on Monday as weak ridging builds in
aloft under southwest flow.
The surface boundary lingers nearby during the day, keeping
clouds and shower/thunder chances in the afternoon and evening,
though coverage appears to be much more scattered than on
Sunday. BUFKIT profiles continue to indicate modest instability
so have maintained the thunder chances into Monday evening.
By late Monday, a positively tilted upper trough begins to
drop into the Lower 48 over the Great Lakes. This energy pushes
the pesky stationary front offshore and helps to dry us out
Monday night, though conditions will remain mild and humid.
Temperatures bottom out in the 60s and lower 70s overnight as
rain chances gradually diminish. Generally followed a superblend
of guidance for this update.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
No significant changes to the extended. Surface low pressure
associated with an upper low allows a warm front to approach
the area by late in the day Tuesday. So while Tuesday looks to
remain mostly dry at this point, clouds will be on the increase
with increasing shower chances by Tuesday night.
The cold front then approaches on Wednesday, providing additional
precipitation chances. While the better upper forcing resides north
of the area, and with PWATS around 1-1.5", there is a 15-20% chance
of >1" in 6 hours per latest NBM, especially north and west of NYC.
The front heads offshore by late Wednesday, with high pressure then
building in on Thursday and Friday ushering a cooler and drier
airmass.
The humidity will continue though Wednesday, with dewpoints
continuing into the upper 60s and low 70s. High temperatures
however will remain in the upper 70s and lower 80s through the
period given the cloud cover and precipitation. Lower humidity
air works in Wednesday night behind the cold front passage.
Long period swells will begin to build late Wednesday through
Friday from distant tropical cyclone Lee that may result in high
surf conditions and dangerous rip currents across the Atlantic
facing beaches. Monitor https:/www.weather.gov/okx/tropical or
https:/www.nhc.noaa.gov for the latest NHC forecasts on
Hurricane Lee and others.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
A stationary front will remain to the NW of the area today with
a surface trough in close proximity.
This is a low confidence forecast with respect to thunderstorms
today as mainly showers will move across the NYC and Lower
Hudson Valley terminals this morning into this afternoon. To
the east, showers will be more scattered in nature. An isolated
thunderstorm cannot be ruled out. Many of the TAF sites do have
TEMPO groups for TSRA this afternoon which continues to be
reevaluated. Thunderstorms may be more isolated than currently
forecast.
Mostly VFR today with periods of MVFR with the showers and
storms. Showers still possible through tonight but with only
enough confidence for PROB30 at this time.
Winds remain light, but directions will vary depending on the
terminal location relative to the trough as well as in/near any
showers and thunderstorms. Generally southerly winds under 10
kt through this evening before becoming more variable overnight.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing for showers/tstms may be off by a couple of hours.
The afternoon haze potential forecast is YELLOW...which implies
slant range visibility 4-6SM outside of cloud.
OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
Monday: MVFR early, otherwise mostly VFR with showers/TSTM/MVFR
possible.
Tuesday: Mainly VFR. Chance of showers and thunderstorms.
Wednesday: Showers likely with MVFR to IFR possible. Chance of a
thunderstorm.
Thursday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
With a weak pressure gradient in place, winds and seas will remain
below SCA thresholds through Tuesday.
Swells from distant Hurricane Lee then build midweek, with SCA seas
likely developing on the ocean by Wednesday. Ocean seas may reach 10
to 15 ft by late Friday resulting in high surf and dangerous rip
current conditions.
Monitor https:/www.weather.gov/okx/tropical or
https:/www.nhc.noaa.gov for the latest NHC forecasts on Hurricane
Lee and others.
&&
.HYDROLOGY...
Slow-moving showers and thunderstorms this afternoon and
evening could be capable of heavy downpours leading to isolated
flash flooding, primarily across NYC, NE NJ, the lower Hudson
Valley, and SW CT. Rainfall rates of 1 to 1.5 inches an hour is
possible in these areas.
Additional shower and thunderstorm activity on Monday may lead
to more nuisance type flooding of urban and poor drainage areas,
though a more significant flood threat appears unlikely.
Slow moving showers and thunderstorms may result in minor/nuisance
flooding on Wednesday afternoon. Otherwise, no widespread hydrologic
impacts are expected Monday through Friday.
&&
.TIDES/COASTAL FLOODING...
The rip current risk today is low for all Atlantic-facing beaches.
The risk increases to moderate for all beaches on Monday, as
long period SE swells begin to arrive from distant Hurricane
Lee.
High surf as well as dangerous rips are possible along the
oceanfront through the remainder of the week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DR
NEAR TERM...DR/JT
SHORT TERM...DR
LONG TERM...DBR
AVIATION...JC/DW
MARINE...DR
HYDROLOGY...DR
TIDES/COASTAL FLOODING...