733
FXUS61 KOKX 172340
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
640 PM EST Tue Dec 17 2024
.SYNOPSIS...
High pressure passes over the area tonight and early Wednesday.
Another frontal system will approach on Wednesday and move
across the area Wednesday night. High pressure briefly returns
on Thursday into early Friday before a clipper system passes
along with an offshore low pressure late Friday into Saturday.
High pressure then builds late in the weekend into early next
week.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
Forecast remains on track. High pressure builds into the area
tonight with light winds and clear skies expected. Good
radiational cooling will allow temperatures to drop into the 30s
for most locations, with a few upper 20s possible in the
normally colder spots.
&&
.SHORT TERM /WEDNESDAY NIGHT/...
Surface high pressure moves offshore Wednesday morning.
Meanwhile, another shortwave trough will drop across the Great
Lakes sending another frontal system toward the area. The
associated warm front and cold front pass through quickly during
the first half of Wednesday night with a quick shot of
rainfall. Rain is expected to overspread the area from SW to NE
Wednesday afternoon/evening, and should end across eastern
sections before daybreak Thursday. Temperatures remain warm
enough for just plain rain this event with the cold air
advection lagging behind the cold front.
Highs on Wednesday will remain above normal, topping out in the
mid 40s to lower 50s, with lows dropping into the 30s for most
locations by daybreak Thursday.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Confidence continues to increase on minimal impacts from a
passing clipper system Friday into Friday night and offshore
low pressure Friday into early Saturday. Confidence has also
increased on the coldest air mass of December 2024 this weekend
into the start of next week.
Key Points:
*A clipper system passing across the northeast on Friday into Friday
night may interact with an offshore low Friday night into
early Saturday to bring some light snow and/or light snow/rain
mix near coast.
*An arctic air mass likely follows the rest of the weekend into
next Monday with potential for several areas, especially
inland, not rising above freezing for at least 3 consecutive
days. Temperatures may begin moderating next Tuesday.
Brief high pressure on Thursday will lead to dry conditions
with temperatures near normal in the lower and middle 40s.
Attention quickly turns to an amplifying upper trough over the
eastern states and developing offshore low pressure on Friday.
There will also be a vortmax off the southeast coast that will
induce low pressure development early Friday. There will be
multiple areas of energy within the trough with the lead vort
energy helping keep the developing low off the coast, which
prevents any direct impacts over the area. However, the guidance
has been inconsistent on any precip from the trailing
energy/clipper and if a inverted trough develops somewhere over
the area. The inverted trough and lingering upper trough axis
may be enough to support an area of light precip somewhere over
the area, but confidence in its location and occurrence is low
at this time. Have capped PoPs off at chance given the
aforementioned uncertainty and with the consensus of the latest
guidance keeping the low far enough offshore. If there is any
light precip development, it would mainly be in the form of
light snow although some light rain could mix in at the coast.
Surface temperatures Friday afternoon/evening look marginal near
the coast, but wet bulb cooling supports the mix becoming all
light snow Friday evening into Friday. A light accumulation is
possible if this scenario were to verify, but there is equal
chances of conditions remaining mostly dry as well. Highs on
Friday look to range from the middle 30s inland to around 40
near the coast.
The upper trough axis swings to the east on Saturday allowing
precip chances to decrease through the day. Conditions should
trend dry and cold the second half of Saturday as a cold, high
pressure starts building towards the region. Highs on Saturday
range from lower to middle 30s.
The high pressure continues to build in Saturday night through
Sunday bringing arctic air to the Tri-State. This air mass looks
colder than the one that occurred this past weekend with 850 mb
temperatures across the northeast -17C to -21C. Have gone closer
to the NBM 50th percentile during this time period as the NBM
deterministic appears too warm, especially near the coast where
it lies above the 75th percentile. Strong cold advection under
northerly flow will bring temperatures down into the teens for
most spots with around 20 in the NYC metro by Sunday morning.
Breezy conditions (N winds 10 mph with gusts 15-20 mph) will
make it feel like it is in the single digits early Sunday
morning. For Sunday, highs will only be in the middle to upper
20s with wind chills largely in the teens. It looks even colder
Sunday night with lows in the single digits inland and teens
near the coast. Winds look lighter Sunday night as the high
pressure settles over the northeast, but any breeze may make it
feel like the single digits. The high pressure remains over the
area Monday with temperatures ranging from the upper 20s inland
and low 30s near the coast. Conditions may begin to moderate on
Tuesday, but highs still will be below normal.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
High pressure builds into the region tonight and moves offshore
Wednesday. A weak area of low pressure approaches to the west
late Wednesday afternoon, and moves over the area Wednesday
evening.
VFR. Becoming MVFR toward 22Z with light rain developing.
Light westerly winds become light and variable late this evening
and into the overnight. A southerly flow develops by midday, and
then as the low approaches late in the forecast winds shift to
the east to southeast.
...NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
No unscheduled amendments until late Wednesday afternoon.
OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
Wednesday night: MVFR-IFR with light rain and fog. Rain tapers
off late Wednesday night, mainly at the NYC metro terminals and
west. NW gusts 15-20 kt late Wednesday night.
Thursday: VFR. NW gusts 15-20kt.
Friday: VFR, becoming MVFR, IFR at times, afternoon into night.
A chance of rain and/or snow during afternoon. A chance of snow at
night. NW gusts late at night 15-20 kt.
Saturday: MVFR to IFR with a slight chance of snow, ending late in
the afternoon. NW gusts 20-25 kt.
Sunday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Winds and seas continue to diminish on the area waters. The
small craft advisories remain in effect through 1am for the
central and eastern ocean waters as seas continue to gradually
diminish as high pressure builds into the region. There is a
chance that seas could fall faster than forecast.
We should see a lull in the SCA condition through much of the day
Wednesday then winds and seas increase once again Wednesday night
with the passage of a cold front.
SCA conditions, mainly in seas, will continue Thursday morning.
These conditions should subside by evening with sub SCA winds and
seas Thursday night into Friday. An offshore low passes the waters
Friday night into Saturday bringing the next chance of SCA
conditions, especially on the ocean. Winds look marginal, but ocean
seas should build to 5-6 ft. The marginal SCA winds may continue on
Sunday with seas near 5 ft.
&&
.HYDROLOGY...
There are no hydrologic concerns through the beginning of next
week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 1 AM EST Wednesday for ANZ350-353.
&&
$$
SYNOPSIS...BC/DS
NEAR TERM...BC/DS
SHORT TERM...BC
LONG TERM...DS
AVIATION...MET
MARINE...BC/DS
HYDROLOGY...BC/DS