discussion on 2023-11-07

000
FXUS61 KOKX 071528
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1028 AM EST Tue Nov 7 2023

.SYNOPSIS...
-- Changed Discussion --A cold front moves across late this afternoon into the evening.
High pressure briefly builds into the area tonight into
Wednesday. The next low pressure and associated frontal system
impact the area Wednesday night into Thursday. High pressure
then builds Friday into the weekend.-- End Changed Discussion --

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --Late this morning, mainly dry conditions will prevail across the
region as the region is placed in the warm sector with an
approaching cold front. This cold front is expected to move
across the region from NW to SE from late this afternoon through
early this evening.

Any rain shower activity is expected to be southeast of Long
Island but a shower or two could develop in and around the
South Fork late this morning. Otherwise, though, dry conditions
are expected and with the cold front moving in late today into
this evening. Larger scale models depict dry conditions and
showers dissipating before reaching the area.

However, mesoscale models do depict some isolated to scattered
shower activity developing and moving across parts of the region
with the cold front early this evening. Coinciding with this is
a mid level vorticity maximum moving across is some low level
instability of a few hundred J/kg according to the
RAP13. Will monitor mesoscale model trends, and see if these
showers increase or decrease in subsequent models runs. May need
to add in the possibility of some rain showers with the cold
front if the mesoscale models trends up with the shower
coverage. One mitigating factor for the showers is the very dry
air aloft which may limit the shower coverage considerably.
There will be a lot of westerly flow throughout the troposphere.

Also, pressure gradient increases and breezy conditions are
expected. A well mixed W-SW flow sets up into the afternoon
before shifting to the NW behind the front. This will bring
gusts around 20-25 mph, strongest near the coast. The other
story today will be the warmer air ahead of the cold front.
Highs look to reach the middle and upper 60s with potential for
a few spots in urban NE NJ to briefly touch 70 degrees.

The aforementioned upper trough amplifies over the Maritimes
tonight as a building ridge approaches from the west. High
pressure will begin ridging down out of southern Canada helping
to bring a much cooler and drier air mass. A breezy NW wind is
expected tonight with temperatures falling through the night.
Dew points will also drop under cold advection. Lows will fall
into the lower to middle 30s inland to the upper 30s and lower
40s elsewhere. Do not think winds will decouple or completely
drop off early Wednesday morning, which will prevent radiational
cooling and any frost development where temperatures fall into
the low-mid 30s.-- End Changed Discussion --

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
High pressure will continue at the surface on Wednesday with
the upper ridge axis moving overhead. Much of the day should be
mostly sunny with high clouds increasing in the afternoon ahead
of the next shortwave over the northern Plains. Highs will be
about 5 degrees below normal in the upper 40s inland and lower
50s closer to the coast.

The surface high will weaken Wednesday evening and shift east
of the area to the New England coast. The upper ridge axis will
also slowly shift to the east Wednesday night. The shortwave
tracks towards the Great Lakes and southern Canada Wednesday
night into Thursday. This will send the next frontal system
towards the region. The warm front approaches Wednesday night
with warm advection taking place out of ahead of it. The
guidance indicates a narrow band of strong middle level
frontogenesis shifting from southwest to northeast late
Wednesday night into Thursday morning. This is along the
middle level warm front, which looks to shift to our northeast
through Thursday morning. The most organized large scale forcing
should remain to our NW and have capped PoPs off at chance
during this time period. Mainly areas of light rain are
expected, especially late Wednesday night into Thursday. While
temperatures may fall well into the 30s inland, they should
remain above freezing. Middle level temperatures will warm with
the passage of the middle level warm front. Any wintry mix is
expected to remain to our north across higher elevations.

The low pressure and associated frontal system will continue
to move across the area on Thursday. The warm front could stall
near the coast during the day with the surface low riding along
it through the afternoon. The organized large scale forcing
remains to the north, but light overrunning rain is possible at
any point during the day, especially if the warm front remains
just to the south. Temperatures are challenging on Thursday due
to the uncertain placement of the warm front. The spread in the
NBM is quite large with the 10th percentile (warm front stays
south of Long Island) showing highs in the in the upper 30s to
low 40s inland and middle 40s to low 50s near the coast. The NBM
90th percentile (warm front lifts north through the region)
gives highs in the upper 50s and low 60s inland to middle and
upper 60s closer to the coast. Have gone with a middle ground
approach and used the NBM 50th percentile for highs on Thursday,
which yield readings in the upper 40s to low 50 inland and
middle to upper 50s near the coast.

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The long term looks to be dominated by a large scale high
pressure system under fairly zonal midlevel flow.

A nose of weak surface high pressure builds into the area from
the west Thursday night and into Friday in the wake of a
frontal system departing to the east. Mid-level energy swiftly
moving through the Ohio Valley and Great Lakes region will
provide for some additional forcing for ascent along the cold
front positioned to the south. This will likely produce a
frontal wave that develops along it that may attempt to push
some light rain toward the region again on Friday but guidance
has become more consistent in keeping this precipitation to the
south of the area. At a minimum, this may result in some
additional cloud cover for Friday.

The frontal disturbance moves eastward Friday night with the
main center of a strong high pressure building into the region
from the west through the weekend. While the weekend is expected
to be dry, a NW flow from the high pressure building in will
likely result in cooler than average temperatures for the
weekend and into the beginning of next week where highs may not
climb out of the 40s.

A frontal system may then impact the area at some point early
next week, but global models do not have a consensus on
strength, timing, or placement.

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --VFR as low pressure passes to the north, and a trailing cold
front approaches late today and moves through this evening.

SW-WSW winds are taking longer to increase than originally fcst
due to thick mid/high level cloud cover. More frequent gusts
may not materialize until these clouds move east.

Winds veer W late this afternoon and then shift NW right of 310
mag with cold fropa this evening. NW winds 10-15G20-25kt
expected tonight. There may be a brief lull late tonight before
gusts resume daytime Wed.

...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

More frequent gusts likely this afternoon after overcast
high/mid level clouds move east...after 17Z-18Z per latest
satellite.

OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...

Wednesday: Chance of MVFR or lower in rain at night, otherwise
VFR.

Thursday: Chance of MVFR or lower in rain, mainly daytime.

Friday: Mainly VFR.

Saturday: VFR.

Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --

.MARINE...
-- Changed Discussion --No changes were made to headlines on the waters. S-SW flow will
continue to increase through the morning. Winds will reach 25
kt first on the ocean and then the non-ocean waters through the
morning. Winds will fall below 25 kt on the non-ocean waters
this afternoon, but should remain around through this evening.
Winds likely become more marginal SCA overnight, but ocean seas
will be 5-6 ft. Winds will remain below SCA levels Wednesday
through Thursday, but seas may remain near 5 ft east of Fire
Island Inlet through midday Wednesday.

While there may be a brief period of gusts approaching 25 kt and
seas on the ocean approaching 5 ft Friday afternoon, sub-SCA
conditions are expected Thursday night through the weekend under
generally high pressure.-- End Changed Discussion --

.HYDROLOGY...
No hydrologic impacts are expected through early next week.

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 3 PM EST this afternoon for ANZ331-
332-335-338-340-345.
Small Craft Advisory until noon EST Wednesday for ANZ350-353.
Small Craft Advisory until 4 AM EST Wednesday for ANZ355.-- End Changed Discussion --

SYNOPSIS...DS/MW
NEAR TERM...JM/DS
SHORT TERM...DS
LONG TERM...MW
AVIATION...BG/MW
MARINE...DS/MW
HYDROLOGY...DS/MW