417
FXUS61 KOKX 270609
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
209 AM EDT Fri Sep 27 2024
.SYNOPSIS...
A cold front slowly pushes through the region tonight. High pressure
briefly noses in during Friday before giving way to a complex
frontal boundary to the south Friday night. High pressure will then
build again slowly late Saturday through early next week. Low
pressure passes to the south Tuesday into Wednesday, followed by a
frontal passage late Wednesday into next Thursday.
&&
.NEAR TERM /THROUGH TODAY/...
-- Changed Discussion --
Scattered showers are developing behind the southward push of a
weak outflow boundary from a line of more moderate convection
earlier in the evening in southern CT. Showers will continue to
develop for the southern half of the CWA through the early
morning hours but should remain fairl like to locally moderate
in intensity.
While there will be a wind shift with the front, the overall
flow is weak so will include patchy fog late tonight into early
Friday morning. PoPs trail off from N to SE across the area
after 6z as the front progresses south. Additional rainfall
amounts should vary between a tenth up to a half inch, with the
half inch amounts likely confined across north and northeastern
zones. With clouds and higher dew points expect very little
temperatures spread once again, with temperatures primarily in
the 60s for lows as dew points are also expected to be in the
60s.
During Friday the area will be on the southern edge of a 500 mb
confluence zone with a NW flow aloft attempting to get established.
However, this feature is no longer progged to get as far south as it
was a few days ago and continues to trend further north and
northeast with subsequent model runs. There should be enough of a
push of surface high pressure into the Lake Ontario region during
the day Friday to keep the region primarily dry as BUFKIT soundings
have pockets of dry air throughout the column. With a lack of lift
it should remain primarily dry. Have maintained slight chance PoPs
along the southern periphery of the CWA more for continuity
purposes, but the theme here is it stays dry during the day, but
with clouds lingering. Expect a mostly cloudy Friday as BUFKIT
sounding consensus is suggestive of 3 different cloud layers with a
low, low-mid, and high deck. The winds are expected to be weak, with
light winds mainly onshore. Temperatures will be running near normal
with highs in the lower and middle 70s.-- End Changed Discussion --
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SATURDAY/...
Friday night should be primarily dry for much of the first half of
the night. After 6z Saturday the confluence zone aloft gets further
away to the northeast and the chances for light rain / showers and
sprinkles will increase from southwest to northeast. Towards
daybreak introduce likely POPs for mainly southwestern portions of
the area as an occluded and complex boundary down to the south
inches a bit closer. Have PoPs trailing off some heading ENE across
the area. Forecast soundings show the lower 10-15 kft moistening
into early Saturday. Look for Saturday to be unsettled with pockets
of light rain pivoting through from time to time. An easterly flow
picks up some towards late morning and afternoon, so not the best of
fall days. Expect periods of rain / showers, with the relatively
higher chance of rain further to the southwest. There remains
uncertainty regarding how much to the northeast the closed upper
level low feature to the southwest over the Ohio and Tennessee
Valley can ultimately get. This will ultimately determine how
unsettled the first half of the weekend gets as there remains a fair
amount of guidance that keeps the mid levels dry, with only the
lowest 5-7 kft remaining moist with relatively higher RH. Late in
the day and evening high pressure from the north will attempt to
nose south once again.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
The overall forecast thinking has not changed much in the long term
and continued to stay close to the consensus forecast using the
latest NBM.
The region will lie between two upper level lows this weekend, one
across the Tennessee and Ohio Valleys and one near the Canadian
Maritimes. Ridging will lie over the northeast between the two lows.
The upper low to our west will slowly weaken and slide east towards
the Middle Atlantic coast early next week with the second low moving
further offshore. The guidance is still differing in the speed and
handling of the upper low to the west, but the overall impact to the
region will be minimal. Despite the differences, there should be
weak surface low development just off the Middle Atlantic sometime
Monday night into Tuesday. The low then slides south and east of the
area through Wednesday. The 12z guidance is starting to come into
better agreement with the low far enough from the coast to limit how
much precip could make into the area. NBM deterministic PoPs are
still in chance category and this seems reasonable given the
uncertainty this far out with the evolution of the upper levels. The
other feature will be continued high pressure ridging down across
the northeast Saturday night through at least Tuesday. The high
should begin to weaken on Wednesday in response to a progressive
northern stream trough approaching the from the west. An associated
front will move across sometime late Wednesday into Thursday, likely
weakening as it moves towards the coast.
Warm advection showers will continue trying to push north into the
southern half of the area Saturday night into Sunday. The main
negating factor will be increasingly dry subcloud air associated
with the high over northern New England building southward. Do not
want to completely rule out a few spots getting a trace to a
hundredth or so of rain near the coast Saturday night into early
Sunday and have maintained low PoPs with this forecast package. The
surface ridging should take over late Sunday into Monday with mainly
dry conditions before chances for showers exists Tuesday into
midweek due to the offshore low and expected frontal passage.
Sky conditions should remain mostly cloudy for much of the period.
The atmosphere should dry out considerably once the front passes mid-
late week. Temperatures look to remain close to normal levels.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
A cold front with post-frontal showers sags south of the coastal
terminals the next 1-2 hours. Conditions dry out today with
high pressure building in from the north.
Based on improvement behind the cold front to the north, have
opted to improve conditions quicker this morning. However, still
expect a period of IFR/LIFR as the front drops across the NYC
and LI terminals. This may be more occasional than frequent.
Improvement to MVFR 2 to 4 hours behind the front and then VFR
developing in the 09Z-15Z timeframe, quickest as KGON and KSWF
where drier air filters in on a northerly flow.
Chance of MVFR returning tonight, mainly at the NYC terminals
as a warm front approaches from the south. There is a low chance
of showers.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Confidence in cig forecast is low. Potential for some terminals
to not lower to IFR.
Timing of improvement to VFR may vary by 1-2 hours.
OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY...
Friday PM: Chance of MVFR, mainly as the NYC terminals.
Saturday: Chance of MVFR in showers with the best chance being
across the NYC terminals.
Sunday: Chance of MVFR in showers.
Monday: VFR.
Tuesday: MVFR/IFR with a chance of showers.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Small craft seas are expected to subside closer to 4 ft for
the western and central ocean waters towards midnight, and
lingering a bit longer into the early morning out on the eastern
ocean. Sub small craft conditions follow for Friday through
Friday night as the winds become more easterly. There is an
increasing chance of small craft conditions returning into the
day Saturday out on the ocean, particularly the western ocean as
5 ft seas return along with marginal small craft gusts with an
increasing easterly flow.
Winds should largely remain below SCA levels Saturday night through
Tuesday. Seas around 5 ft are possible Saturday night before
subsiding to around 4 ft Sunday night into Monday. Seas build back
to 5-6 ft Monday night into Tuesday with the development of low
pressure offshore.
&&
.HYDROLOGY...
There are no hydrologic concerns through the middle of next
week.
&&
.TIDES/COASTAL FLOODING...
There is a moderate rip current risk Friday as swells subside a
bit with weaker winds. The risk may start out moderate Saturday
before becoming high in the afternoon as seas and swells build
along with a stronger easterly flow.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EDT early this morning for
ANZ350.-- End Changed Discussion --
&&
$$
SYNOPSIS...JE/DS
NEAR TERM...JE/DS/JT
SHORT TERM...JE
LONG TERM...DS
AVIATION...DW
MARINE...JE/DS
HYDROLOGY...JE/DS
TIDES/COASTAL FLOODING...