790
FXUS61 KOKX 120647
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
247 AM EDT Sat Oct 12 2024
.SYNOPSIS...
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High pressure will reside south of the area tonight. A cold
front swings through Saturday and stalls to the south Saturday
night. The front lifts north as a warm front late Sunday into
Sunday night along with developing low pressure. The low drags a
cold front through Monday morning into Monday afternoon, with
high pressure slowly building in thereafter.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH TODAY/...
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No significant changes with this update or forecast thinking.
Clear skies and modest WNW flow continue as a sfc trough
lingers nearby tonight before moving further offshore late.
Previous discussion follows.
Mainly clear skies are expected with deep layer WNW flow. A
light WSW flow closer to the sfc gets established as the night
progresses ahead of a cold front which starts to approach
getting closer to daybreak. With some weak low level warm
advection not expecting temperatures to get as cool as previous
nights as dew points get into the middle 40s for the most part.
This puts a floor on how much temperatures can fall. Any cloud
cover tonight will be high up and quite thin as latest guidance
has less in the way of cirrus compared to previous guidance.
Lows be in the lower and middle 50s along much of the coast,
with some upper 50s in the metro. Some upper 40s and lower 50s
are expected in far northern and northwestern outlying locales.
A good start to the weekend is expected despite the fact that a
cold front begins to push through primarily for the morning. A
shortwave across the Northern Great Lakes region will dive
across and clip Northern New England early in the morning. This
shortwave passes far enough to the north that this will be a dry
frontal passage with virtually no moisture for the front to
interact with. As a matter of fact there should not even be much
in the way of cloud cover with the front. Perhaps only a few
upper level clouds that may only slightly filter the sunshine
for a time. Otherwise, a mostly to partly sunny day will be on
tap. Temperatures should average a few degrees above normal as
temperatures should reach the lower half of the 70s across a
majority of the area, with perhaps a few upper 60s to the NW.-- End Changed Discussion --
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/...
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During Saturday night the cold front that pushes through earlier
on Saturday is expected to stall across the Mid Atlantic
states. The next shortwave feature on deck for late in the
weekend will still be back over the Northern Rockies for
Saturday and moving across the Northern Plains and portions of
the Midwest Saturday night. That will leave the region in-
between a trough exiting the northeast, and the approaching
shortwave over the Midwest. Some higher level clouds, and
perhaps some mid levels clouds start to gradually work in during
Saturday night. Across the majority of the region it will
remain dry. However, across far NW portions of the area (Orange
County) start slight chance PoPs late with weak positive
vorticity and thermal advection. Low pressure develops in the
Ohio Valley late at night and into Sunday morning. This will
lead to the frontal boundary lifting north as a warm front into
the day on Sunday. The difficult part of the forecast pertains
to whether there will be enough in the way of some mid and high
level clouds to prevent frost formation across northern and
northeastern portions of the region. The winds will be light,
but the amount of cloud cover is a bit uncertain. For now
thinking there will not be frost formation as the air mass will
likely not be cold enough, but some isolated frost cannot be
completely ruled out across northern most portions of CT and the
Hudson Valley. Lows are progged to be in the upper 30s and
lower 40s along the northern periphery of the CWA, otherwise 40s
and lower 50s in most places.
Low pressure develops further to the west Sunday morning and
lifts to the N and NE into Sunday afternoon and evening. This
should drag the stalled boundary to the south north as a warm
front. A lot of the upper level support will lag back to the
west and get aimed north of the area. Thus, likely PoPs will be
reserved for northwestern portions of the area, with chance PoPs
getting further south and east for the later morning and
afternoon on Sunday. Any rain / shower activity is expected to
light. Rainfall amounts through the day Sunday will around or
just above a tenth of an inch across far northwestern sections,
with just a few hundredths elsewhere. Some places along the
southern periphery of the CWA may not getting anything
measurable through the day on Sunday. A mostly to partly cloudy
day is anticipated, with the relatively more clouds and a higher
chance of showers the further north and west one is.
Temperatures will range from near 60 across far northern areas
where there is more cloud cover, to the upper 60s and a few
lower 70s across far southern portions of the area.-- End Changed Discussion --
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
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Sunday evening starts out with a deepening upper level trough
approaching from our west. The associated surface low at that
time should be centered somewhere over western PA, with its warm
front extending just north of our area or over northern
portions of the area. The low will deepen as it approaches and
will likely pass just over or near the area early Monday
morning. Its cold front then passes through later Monday morning
into the afternoon, ushering in the coolest airmass of the
season.
In terms of weather, this system will bring rainy and windy
conditions. There is still some spread across the guidance,
but general consensus has the most likely period of rain being
Sunday night. PoPs don`t end until Monday night with the chance
for some lingering rain through the day on Monday and the
possibility of the front moving through later. With some
instability available and strong lift, thunder can not be ruled
out and have added to the forecast for Sunday night. The
heaviest totals will likely be well north of the area, with an
average total of a few tenths for us. Amounts will be locally
higher in any thunderstorms. We could see some gusty southerly
winds ahead of the frontal passage, but the stronger winds
likely come later on Monday behind the front with cold advection
in a W/NW flow. Even mixing down winds from halfway up the
model mixed layer supports gusts in the mid to upper 20 kts.
Blended in NBM 90th percentile gusts to show this. The gust
forecast could continue to trend up.
Dry conditions expected thereafter, with high pressure very
gradually building in. Gusty conditions could continue as the
pressure gradient remains relatively tight. Dewpoints drop to
the low to mid 30s by Monday night and likely stay there through
the end of the week. While the winds remaining elevated do not
support radiational cooling, the cool airmass itself will bring
lows in the mid 30s to low 40s for the rest of the week. This is
well below average for early October.-- End Changed Discussion --
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
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VFR as a dry cold front approaches and passes through after
daybreak, and high pressure builds in during the afternoon and
at night.
Mainly WSW flow has picked up to 10-15 kt at KJFK/KLGA and
remains under 10 kt elsewhere. Fropa 12Z-13Z with winds shifting
out of the NW 10-15G20-25kt, diminishing late in the afternoon.
LLWS possible before fropa, with NW flow 35-40 kt at FL020.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Stronger NW winds could last an hour or two longer into the
afternoon than fcst.
OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
Late tonight: VFR.
Sunday: Chance of showers with VFR for much of the time.
S winds 10-15G20kt in the afternoon at the metros and along the
coast.
Sunday night: Showers likely, possibly an evening tstm.
MVFR cond possible especially inland. S-SW winds 10-15G20kt in
the evening at the metros and along the coast.
Monday: Showers likely with MVFR cond in the morning,
especially at the Long Island/CT terminals, ending in the
afternoon. W winds becoming 15G20-25kt increasing to
15-20G25-30kt in the afternoon.
Monday night: VFR. W wind 15-20G25-30kt early, becoming NW
10-15G20kt by late evening.
Tuesday: VFR. W winds 15G20-25kt.
Wednesday: VFR. NW winds 10-15G20-25kt.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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Small craft conditions develop on the ocean waters this evening
on a W to NW wind. Marginal small craft conditions are likely
for the eastern half of LI Sound late tonight and through the
morning. Small craft conditions on the ocean should continue
through the midday for the western half of the ocean, and until
late afternoon for the eastern ocean waters as a NW wind will
diminish during the afternoon hours from west to east. Winds and
seas will briefly remain below small craft criteria Saturday
night into early Sunday morning.
The pressure gradient will tighten once again late Sunday
bringing an extended period of Small Craft Advisory conditions
on the ocean waters and potentially all other waters. 25 kt
gusts could start as early as Sunday evening ahead of the cold
front. On Monday behind the cold front, 20 to 30 kt gusts are
possible on all waters. 25 kt gusts could then linger on the
ocean waters through Wednesday night. The prolonged period of
windy conditions will also cause seas to reach 7 to 8 feet by
Sunday night and remain elevated through Monday night. Sub Small
Craft Advisory conditions expected by the end of next week.-- End Changed Discussion --
&&
.HYDROLOGY...
There are no hydrologic concerns through the forecast period.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 4 PM EDT this afternoon for ANZ350-
353.
Small Craft Advisory until noon EDT today for ANZ355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JE/JT
NEAR TERM...JE/DR
SHORT TERM...JE
LONG TERM...JT
AVIATION...BG
MARINE...JE/JT
HYDROLOGY...JE/JT