000
FXUS61 KOKX 051648
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1248 PM EDT Sat Aug 5 2023
.SYNOPSIS...
High pressure over the Great Lakes builds across the area through
Sunday and then gives way to a frontal system that impacts the
area Sunday night into Tuesday. Weak high pressure briefly builds
in for Wednesday and Wednesday night. Another frontal system
approaches from the west Thursday and lingers in the vicinity of
the region Friday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
High clouds can be seen pouring in from the west on current
satellite imagery. It will be drier and warmer than Friday with
highs in the lower to mid 80s. This is right around normal. A
light flow and daytime heating has allowed for sea breezes to
develop along the Long Island and CT coast. They will be
somewhat limited to the near coast, especially early in the
afternoon, due to the synoptic northerly flow.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
Aloft, the upper trough lifts out of the Northeast with shortwave
ridging building in from the west into Sunday. This will result
in surface high pressure building across the area during this
time.
The high builds east of the area by Sunday evening with a return
southerly flow. At the same time, an amplifying shortwave
trough over the Northern Plains tonight drops southeast into the
Upper Mississippi Valley Sunday, then into the Ohio Valley
Monday. There is decent agreement that multiple convective
complexes eject out ahead of the upper trough, interacting with
a warm front that approaches from the southwest Sunday night
into Monday. Thus, the forecast has trended earlier with chances
for convection moving in as early as Sunday night. There are
likely to be timing issues as is the case with these features.
Guidance also varies with the location of the heaviest rainfall,
but a consensus approach at this time places emphasis to the
north and west of the NYC metro. This will be refined multiple
times as we draw closer to the event. PWAT values approach 2
inches by Monday evening. This anomalous deep layer moisture
flux also coincides with LFQ upper jet dynamics late in the day
Monday. Potential is there for heavy rainfall as we approach
Monday night. As for any severe weather, instability and shear
are weak Sunday night into Monday being ahead of the warm front
and in a strengthening S/SE flow. This will bring more of a
marine influence into the area.
Temperatures remain near normal through Sunday night, but it
will become more humid heading into Monday with a strengthening
southerly flow. Due to increasing cloud cover Monday ahead of
the warm front, temperatures are forecast to be a bit cooler.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Monday night into early Tuesday there is dynamics aloft signaled by
the forecast models. The features conveyed include parallel flow
lower to upper levels, upper level jet streak maxima SW to NE
orientation moving in, presenting divergence aloft. Layer PW maximum
near 1.9 to 2 inches moves in Monday night into Tuesday morning.
At the surface, a warm front moves in from the south Monday night
into Tuesday morning. This will be part of a frontal system
approaching from the west. The associated cold front moves through
during the day Tuesday. Much of the rain with this system appears to
be with the warm front Monday night into early Tuesday with the
development of showers and thunderstorms. Showers and thunderstorms
still in the forecast Tuesday afternoon into early Tuesday evening.
Convective activity then tapers off with drier conditions returning
later Tuesday night.
Weak high pressure gradually moves in behind this frontal system as
it moves near Gulf of Maine and eventually the Canadian Maritimes
for Wednesday. The high pressure remains in the area through
Wednesday night before moving offshore Thursday. Another frontal
system then approaches Thursday night into Friday bringing the next
chances of showers and thunderstorms.
High temperatures staying in the 80s Tuesday through Friday with
upper 80s for Northeast NJ and the NYC Metro Area. More humid
conditions forecast Monday night through Tuesday and towards the end
of the forecast period Thursday night and Friday when forecast
dewpoints are more in the upper 60s to lower 70s.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
High pressure builds in from the northwest for the TAF period
with VFR.
Light N-NW flow becomes more southerly this afternoon for
coastal terminals as sea breezes develop. As sea breezes
diminish this evening winds will become light northerly. A few
terminals will become light and variable tonight.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Sea breeze timing at JFK may be off by 1-2 hours. The sea breeze
is not expected to reach the other terminals.
OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY...
Sunday: VFR.
Monday: Chances of showers and thunderstorms with MVFR or lower
conditions.
Monday night-Tuesday: Showers with MVFR or lower conditions. A
chance of thunderstorms.
Tuesday night-Wednesday: Mainly VFR. W-WNW wind gusts around 20 kt
Wednesday.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Wind and seas will subside as high pressure builds across the
water this weekend. An increasing southerly flow ahead of a
frontal system Monday may produce marginal SCA wind gusts and
seas on the ocean late in the day.
For the long term marine forecast Monday night through Wednesday
night, below SCA conditions forecast Monday night through Tuesday.
SCA wind gusts forecast Tuesday night into Wednesday on the ocean
and for non-ocean eastern waters on Wednesday. SCA level seas
forecast Tuesday night into Wednesday on the ocean. The forecast
ocean seas lower below SCA Wednesday night with wind gusts below SCA
thresholds. The non-ocean waters conditions remain mainly below SCA
thresholds Tuesday night through Wednesday night with the exception
of the aforementioned eastern non-ocean waters on Wednesday for wind
gusts.
&&
.HYDROLOGY...
Heavy rain is possible at times Monday night into Tuesday with a
localized flash flood threat. WPC has western portions of the
area under a Marginal Risk for Excessive Rainfall. Otherwise,
minor flooding will be possible in low lying, urban, and poor
drainage areas that receive multiple episodes of heavy rain.
&&
.TIDES/COASTAL FLOODING...
There is a moderate risk of rip current development along Atlantic-
facing beaches today due to a 2-3 ft S swell at 8-9s. For
Sunday, latest RCMOS still supports moderate with a continued
swell, however, this may be more of a marginal situation as seas
on the ocean will be lowering.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JM/DW
NEAR TERM...JT/DW
SHORT TERM...DW
LONG TERM...JM
AVIATION...JM/MET
MARINE...JM/DW
HYDROLOGY...JM/DW
TIDES/COASTAL FLOODING...