000
FXUS61 KOKX 041503
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1103 AM EDT Fri Aug 4 2023
.SYNOPSIS...
A frontal system approaching today will move across the region
tonight. High pressure returns for the weekend. Another frontal
system is expected to impact the area from late Monday into Tuesday.
High pressure builds in briefly Wednesday, followed by another
late week frontal system.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
The forecast is mainly on track this morning. Have lowered PoPs
through the early afternoon as the area is currently dry, with
some spotty showers seen well to the south.
A frontal system is approaching the area from the northwest today
with weak low level warm air advection over the area allowing for
the development of spotty showers, mainly along the coast into
this morning. The stronger forcing with the cold front still
remains well to the northwest and approaches the area this
afternoon, eventually moving through this evening.
Despite increasing low level moisture into this morning, weak
forcing through much of the day will likely allow for mostly
cloud skies with a chance for scattered showers through much of
the day. There doesn`t appear to be enough forcing for any
shower to become deeply vertical to allow for lightning
generation until the afternoon when instability increases as the
temperatures rise a bit. Even then, most CAMs struggle to
develop any convection in the area until very late this
afternoon and into the evening with a line of thunderstorms
developing to the northwest over Central NY, eventually sinking
down into the Lower Hudson Valley and the coastal plain.
SPC places the western half of the area in a marginal risk for
severe thunderstorms with portions of extreme NW Orange COunty
in the slight risk. WPC also places the area in a generic
marginal risk for excessive rainfall. PWATs of near 1.5 inches
may result in heavy rainfall in any thunderstorm, which may
result in localized urban and small stream flooding.
The cold front moves through tonight and the chance of showers
and thunderstorms continues to decrease into the early morning
on Saturday.-- End Changed Discussion --
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Behind the frontal passage, high pressure builds into the region
for the weekend result in generally clear skies and dry
conditions with temperatures moderating a bit. Highs will be in
the low to middle 80s for much of the region. High pressure
shifts over the area and offshore Sunday night giving way to
the next frontal system expected to approach the area on Monday.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
Changes have been relatively minor in the extended period.
A shortwave trough over the Northern Plains over the weekend will
work east across the norther tier of the country. There are some
timing issues with the global models as the feature interacts with a
northern branch shortwave trough dropping southeast across central
Canada and into the Great Lakes. This will likely result in some
timing issues. In the meantime, consensus supports a frontal system
approaching Monday and moving through the area Monday night into
Tuesday. This will result in increasing chances for showers and
thunderstorms Monday afternoon into Monday night. The associated
surface low occludes to northwest of the area with the area in close
proximity to the triple point. Whether or not we can warm sector is
uncertain at this stage, but will determine how much we can
destabilize. Timing of the frontal system moving across the area
will also be an issue which looks to be at night. Right now the
severe weather threat looks to be low. In addition, the system also
looks to be progressive enough to limit the flood threat.
High pressure builds in late Tuesday into Wednesday, then offshore
Thursday with a return southerly flow. A late week frontal system
may be in the offing.
Temperatures will remain near seasonable levels through Thursday,
with moderate humidity with dew points mainly in the 60s, slightly
higher Monday ahead of the cold front.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
A cold front approaching today will move across tonight.
A few showers and ocnl MVFR cigs may dot parts of the area this
afternoon as S-SW wind increase, with some gusts 15-20 kt mainly
along the coast.
Delayed potential for tstms a couple of hours, from about
22Z-01Z for KSWF, to 00Z-03Z for the NYC metros, to 01Z-03Z out
east. Even then, there is uncertainty whether this activity will
be organized or remain mainly scattered in coverage.
Actual cold frontal passage will occur late tonight.
The afternoon haze potential forecast is YELLOW for the NYC
terminals, which implies slant range visibility 4-6SM outside
of cloud.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Ceilings may vary between low end VFR/high end MVFR this
morning.
Best chance of thunderstorms at this time looks to be after
sunset. Low to medium confidence. There is good agreement that
any thunderstorms will be weakening as they approach this
evening.
OUTLOOK FOR 12Z SATURDAY THROUGH MONDAY...
Saturday and Sunday: VFR.
Monday: Chance of late day showers and thunderstorms from NYC
north/west with MVFR or lower cond.
Monday night and Tuesday: Chance of showers/tstms with MVFR or lower
cond.
Tuesday night: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Winds increase and seas build this afternoon and evening ahead
of a cold front. Winds should largely stay below 25 kt, but an
occasional gust to 25 kt cannot be ruled out. Ocean seas should
also build to 4 ft, but should stay below 5 ft. Winds and seas
subside behind the cold front passage late tonight into
Saturday morning.
Winds and seas will remain below SCA levels across the forecast
waters from Saturday morning through Monday evening. With an
increasing southerly flow ahead of a frontal system Monday ocean
seas will likely build to SCA levels by late Monday night and
remain elevated into Tuesday morning. Occasional gusts on the
ocean waters may also be near SCA levels during the same time
period.
&&
.HYDROLOGY...
-- Changed Discussion --
Showers and thunderstorms from late day well NW of NYC, into
this evening elsewhere, may produce locally heavy rainfall.
Minor nuisance poor drainage flooding is in the main threat.
There are no hydrologic concerns from Saturday through the middle
of next week.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
-- Changed Discussion --
There is a moderate risk of rip current development at the
ocean today and Saturday with a 2-ft 9-10 s period S swell.
The threat of minor coastal flooding has ended. A statement may
be possible for the south shore back bays for tonight`s high
tide cycle, but water levels will continue to lower.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DW/MW
NEAR TERM...MW
SHORT TERM...MW
LONG TERM...DW
AVIATION...BG/DW
MARINE...DW/MW
HYDROLOGY...DW/MW
TIDES/COASTAL FLOODING...