717
FXUS61 KOKX 182335
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
735 PM EDT Fri Oct 18 2024
.SYNOPSIS...
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High pressure remains in control until a strong cold frontal
passage near the end of next week.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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Winds have become near calm across much of the area under clear
skies. As a result temperatures in a few outlying locations have
fallen off faster than forecast. Updated for current conditions
and trends into early Saturday morning.
Strong upper ridging takes place through tonight as a strong
surface high continues building into the region, with dry
conditions. The pressure gradient decreases as the high builds
in from the west. Surface winds will diminish and with strong
subsidence, sky conditions will remain mostly clear. The stage
will be set for efficient radiational cooling to maximize
spatial differences in temperature across the region. However,
with 850mb temperatures trending higher tonight compared to the
previous night, surface temperatures will likewise not drop as
much as the previous night.
Using the MAVs for tonight. They have colder temperatures
compared to MET for interior and rural locations. MAVs capturing
the radiational cooling effect better than the NBM. Winds
becoming calm over the interior will make for significant area
of frost for Orange and Putnam counties, covering most of those
forecast zones. Hence, a frost advisory has been issued for
Orange and Putnam from 2AM to 9AM Saturday.
Other zones across the interior and parts of Eastern Long
Island will be cold enough for frost formation but more limited
in spatial areal extent as min temperatures will be more in the
mid to upper 30s. Rest of region along coast and within NYC
mainly in lower 40s to lower 50s range for lows.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Main jet stream gets re-established north of the region through
this weekend. High pressure ridge main dominant feature with a
moderation of the airmass as well as warming trend to
temperatures.
The ridging continues for Saturday. The ridge flattens for the
rest of the weekend with its axis moving out over the Atlantic.
Height falls Saturday night through Sunday as an embedded trough
moves across. Then more of a plateau near steady height tendency
state Sunday night as the trough axis moves farther east over
the Atlantic.
The high pressure area will eventually move south and west of the
local region for the weekend. Surface pressure over the local region
will gradually decrease this weekend. However, the subsidence from
the high will remain strong enough to keep dry conditions prevailing
through the weekend.
The wind flow will eventually become more SW this weekend as the
high pressure settles south and west of the local region, keeping a
pressure gradient from lower pressure to the north to higher
pressure south and west of the local area. This will allow for a
gradual moderation of the airmass, with warmer air advecting into
the region. This becomes more pronounced for Sunday.
High temperatures trend warmer, upper 60s to lower 70s Saturday,
and mainly in the low to mid 70s Sunday. Optimal radiational
cooling conditions each night with a warming trend for lows also
each night. For Saturday night into early Sunday morning, could
again have some frost for parts of the interior north and west
of NYC as well as parts of Pine Barrens on Long Island.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Mild weather thru Wed with a big upr ridge over the East Coast. The
models were in good agreement, so the NBM with minor tweaks was
used. Warm enough temps that a sea breeze may develop on Mon, then
the flow becomes sely on Tue and sly on Wed, keeping most coastal
areas slightly cooler. H85 temps are warm enough to support 80s
areawide Mon and Tue, but the llvl winds do not appear to support
these temps from materializing on Tue. There is a chance on Mon
however with subsidence and wly component flow modeled. Did not go
abv the NBM at this point, but if confidence in the wind flow
increases, would expect some low to perhaps mid 80s across parts of
the cwa.
Dry Mon-Wed with the ridge in place.
Upr trof approaches and a cold frontal passage occurs on Thu per the
current modeling. Timing of the fropa will be critical to high temps
and pcpn chances. An aftn passage would yield warmer temps and
better chances for some isold-sct shwrs/tstms. Not much moisture so
it appears rain chances will be heavily dependent on convection. The
NBM was used for temps keeping things middle of the road. Pops were
kept dry for now with the main h5 energy N of the area.
Colder on Fri. Since the models were in good agreement with the
fropa in general, went with the colder MEX guidance for highs
keeping temps in the 50s across the cwa.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
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VFR with high pressure in control through the TAF period.
Winds light N/NE to light and variable through the overnight and
into early Saturday morning. A light southerly flow develops
Saturday afternoon.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled amendments.
OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY...
Saturday night through Wednesday: VFR.
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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No changes to winds and seas at this time.
SCA conditions remain for the ocean waters through Saturday
night with a SCA currently issued through Saturday night. Gusts
to 25 kt on ocean and ocean seas of near 7 to 10 ft into early
this evening. Gusts subside thereafter tonight into Saturday to
below SCA thresholds and ocean seas eventually decrease to near
5 to 7 ft. Winds continue to weaken and remain well below SCA
thresholds for Saturday night. Sub-SCA conditions eventually
expected for Sunday as waves drop below 5 feet with winds
remaining below SCA levels. Sub-SCA levels for winds and seas
expected for Sunday night.
Winds and waves blw sca lvls Mon-Wed with high pres over the area.
As a cold front approaches, winds increase Wed ngt, with sca
criteria possible all waters on Thu with the front.-- End Changed Discussion --
&&
.FIRE WEATHER...
Recent dry conditions will lead to an elevated spread of
wildfires today with minimum RH values of 25-30 percent. Winds
may also gust close to 20 mph at times. Per collaboration with
NJ, CT fire weather partners, an SPS is out for our NE NJ
counties as well as Fairfield County CT.
&&
.HYDROLOGY...
There are no hydrologic concerns through the middle of next
week.
&&
.TIDES/COASTAL FLOODING...
The most impactful coastal flooding has come to an end with the
passage of the high tide earlier today.
While there looks to be additional minor coastal flooding on
Saturday, it is expected to be brief, more localized and confined to
the south shore back bays of western LI and SW CT. A statement has
been issued for these locations. Water levels will gradually lower
through the weekend due to a diminishing easterly swell and lowering
astronomical tides.
Leaned toward the Steven`s guidance as forecast errors have been
relatively small.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Frost Advisory from 2 AM to 9 AM EDT Saturday for NYZ067-068.
NJ...Frost Advisory from 2 AM to 9 AM EDT Saturday for NJZ002.
MARINE...Small Craft Advisory until 6 AM EDT Sunday for ANZ350-353-355.
&&
$$
SYNOPSIS...JM
NEAR TERM...JM/MET
SHORT TERM...JM
LONG TERM...JMC
AVIATION...MET
MARINE...JMC/JM/MET
FIRE WEATHER...
HYDROLOGY...JMC/JM
TIDES/COASTAL FLOODING...