000
FXUS61 KOKX 031951
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
351 PM EDT Thu Aug 3 2023
.SYNOPSIS...
-- Changed Discussion --
A frontal system approaches tonight into Friday and will move
across the region Friday night. High pressure returns for the
weekend. Another frontal system is expected to impact the area
from late Monday into Tuesday. Weak high pressure builds in
briefly Wednesday. Another frontal system approaches Thursday.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
-- Changed Discussion --
High pressure continues moving offshore this evening. Despite
SE flow increasing this afternoon, dew points have lowered as
drier air has mixed down to the surface. A weak surface trough
has set up mainly across the interior on NW. SPC mesoanalysis
indicated CAPE has started to increase inland. However, model
soundings are still depicting a cape around 15kft. This will
likely inhibit any stronger updrafts from developing this
afternoon and early evening. A few showers are possible late
this afternoon and evening across the interior of NE NJ and the
Lower Hudson Valley. Have removed mention of thunder for this
time period as think the lingering capping is going to inhibit
any parcels from reaching high enough to support lightning
development. The cap does start to weaken this evening, but loss
of heating will lower instability levels.
Otherwise, a frontal system will continue approaching tonight.
Warm advection will begin to increase overnight and could
generate a few showers, especially early Friday morning.
Instability is limited and will continue with just a chance of
showers towards day break. There could be pockets of moderate
rain, but not anticipating any heavy downpours out of this
activity. Lows will be in the middle to upper 60s except around
70 in the NYC metro. Dew points should start rising into the
60s, making it feel a bit more humid.-- End Changed Discussion --
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
-- Changed Discussion --
Closed upper low over Quebec will help amplify troughing and
lower heights over the northeast on Friday. A frontal system
will approach during the day with a pre-frontal trough ahead of
it. Warm advection showers are possible in the morning. There is
also a period in the morning when portions of the area lie in
the left exit of a 70-90 kt 250 mb jet streak.
CAMs are coming into better agreement on the evolution of
convection in the afternoon and evening. There is good
agreement that a line of showers and thunderstorms will develop
well to our north and west along the pre-frontal trough in the
afternoon. The approaching cold front will help push this
activity towards the south and east late in the afternoon and
evening. There is still a decent amount of spread in the timing
of when this activity will make it into the area, but favoring
evening from northwest to southeast. The environment should be
see some destabilization in the afternoon with dew points also
increasing into the upper 60s. Bulk shear may average around 30
kt in the evening, coinciding with when the potential convective
line enters the interior. SPC has placed interior Lower Hudson
Valley and interior NE NJ in a marginal risk with an isolated
damaging wind gust possible. The line is progged to weaken as it
moves south and east through the rest of the evening as it
encounters a more stable environment. If the line ends up
several hours faster, the threat for an isolated severe storm
is possible further south as instability would be higher.
However, showers with some thunder are still expected down to
the coast. Locally heavy rainfall is possible with minor poor
drainage flooding the main concern. The line will be progressive
and currently not expecting training storms to produce more
significant rainfall and flash flooding.
Any lingering showers/storms push off the coast 02-04z with the
cold front making its way offshore early Saturday morning. A
brief shower cannot be ruled out as the front passes offshore,
but overall clouds will begin to diminish and some drier air
begins to filter in from the north towards day break Saturday.
Lows will range from the lower 60s inland to the middle and
upper 60s near the coast.-- End Changed Discussion --
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
-- Changed Discussion --
Near zonal, to low amplitude, upper flow will keep systems
progressive Saturday through the middle of next week. Initially
a low amplitude ridge builds slowly toward the region Saturday
through Sunday morning, with the ridge axis passing to the east
Sunday afternoon. Then a shortwave across the upper plains
Saturday will be digging into the upper midwest Sunday, and then
into the region Monday into Tuesday as the upper flow flattens.
At the surface weak high pressure builds in behind a cold front
Saturday morning, and moves offshore Sunday. A warm front
approaches early Monday and lifts north during the day.
Thunderstorms will be possible in the warm sector Monday, with
little CAPE and surface based instability. Weak high pressure
builds in to the southwest Wednesday into Thursday.
Temperatures will remain near seasonal normal levels Saturday
through Thursday, with moderate humidity with dew points mainly
in the 60s, slightly higher Monday in the warm sector ahead of
a cold front.-- End Changed Discussion --
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
High pressure will move offshore this afternoon. A weak warm
front will move across tonight into Friday morning, followed by
a cold frontal approach late Friday.
S flow will increase this afternoon to 15-20G25kt at KJFK/KLGA,
and to 10-15G20kt at most other metro and coastal terminals.
Winds diminish tonight and then veer more to the SW around or
just over 10 kt after the Fri AM push. MVFR cigs and a few
showers with the warm front should also arrive around that time.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled AMD expected. Cigs daytime Fri could be a little
higher than forecast, just barely VFR.
OUTLOOK FOR 18Z FRIDAY THROUGH MONDAY...
Friday afternoon and evening: Showers/tstms likely with MVFR or
lower cond possible.
Late Friday night: Chance of showers. MVFR cond possible.
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
&&
.MARINE...
-- Changed Discussion --
Southerly winds continue to increase today with a departing
high to the east. An occasional gust to 25 kt is possible near
the NY Harbor and ocean west of Fire Island Inlet. Seas here may
also briefly build to 4 ft. Winds and seas will weaken overnight
and remain below SCA levels into Friday morning. Winds increase
and seas build Friday 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 Friday night 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.-- End Changed Discussion --
&&
.HYDROLOGY...
-- Changed Discussion --
Showers and thunderstorms late Friday afternoon into Friday
evening may produce locally heavy rainfall. Minor urban and 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 beaches today with 2-3 ft 11-12s southeasterly swells,
approaching 3-4 ft late and towards evening. With the long
period swell increasing the rip current risk may increase to
high late in the day and into the evening.
There is a moderate risk for the development of rip currents at
all the ocean beaches Friday.
Astronomical tides remain high with the full moon from Tuesday
evening. Minor flooding is again possible during tonight`s high
tide cycles. A coastal flood advisory remains in effect for
southern Queens and Nassau Counties. Coastal flood statements
remain in effect for Staten Island, Southern Brooklyn, and
Southern Fairfield. A statement may also be needed for the south
shore back bays with Friday night`s high tide, but water levels
will continue to lower.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Coastal Flood Advisory from 8 PM this evening to midnight EDT
tonight for NYZ178-179.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DS/MET
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...MET
AVIATION...BG
MARINE...DS/MET
HYDROLOGY...DS/MET
TIDES/COASTAL FLOODING...