296
FXUS61 KOKX 171455
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
955 AM EST Tue Dec 17 2024
.SYNOPSIS...
A cold front passes through the area this morning, followed briefly
by high pressure tonight into early Wednesday. Another frontal system
will approach on Wednesday and pass through the area Wednesday
night. High pressure briefly builds in again Thursday into early
Friday before an offshore low pressure system potentially impacts
the area late Friday into Saturday. High pressure returns late in
the weekend into early next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Forecast on track with just a few minor adjustments to reflect
current observations. One addition to the forecast was to add
some patch fog to locations east of NYC. Otherwise, a warm
front remain north of the area with temperatures generally in
the lower 50s except for some locations well north and west of
the NYC metro. Those locations will continue to see a
temperatures gradually rise. An approaching cold front over
Pennsylvania will work east of the area by late this morning
Low pressure over eastern Canada will track to the northeast
with high pressure over the Tennessee Valley building into the
area later today through tonight. Skies will clear from NW to SE
into early this afternoon and winds will veer to the W,
becoming gusty (20-25 mph) for a short time late this morning
into this afternoon.
It will be mild day as the airmass lags in response to the cold
advection. Highs will top out in the 50s, about 10-13 degrees
above normal.
High pressure builds in tonight with light winds and clear
skies. Low will drop into the 30s for most locations, with a few
upper 20s possible in the normally colder spots. This is still
several degrees above normal.-- End Changed Discussion --
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
Another fast moving northern stream shortwave trough will drop
across the Great Lakes on Wednesday, 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 moderate rainfall, producing about 0.50 to
0.75". Rain will overspread the area from SW to NE Wednesday
afternoon, and should end across eastern sections before
daybreak Thursday. Cold air advection lags sufficiently behind
the cold front that no wintry weather is expected on the
backside of the system.
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 MONDAY/...
Key Points:
*Forecast area looks to be on the western periphery of an
offshore low that develops over the western Atlantic Friday
into Saturday.
*Below normal temperatures expected over the weekend into early
next week, with highs on Sunday likely not getting out of the
20s.
Guidance continues to show low pressure Friday into Saturday to
be well enough offshore to not impact the area, but there is
still uncertainty with model ensembles with a definite NW jog
sine the 12Z guidance. This will have to be watched, but the
area is still well removed from any significant precipitation.
There is also some interaction with the offshore low that develops
and an approaching shortwave trough that could produce some
precipitation across the area. There would be enough cold air
in place for a snow or rain/snow mix event. Even if this ended
up being all snow, the QPF at this time looks light.
Behind this system, high pressure will build in through the start of
next week and bring a very cold airmass. Highs on Sunday will likely
not get out of the 20s, with some interior locations potentially not
getting out of the teens. There is also potential for 10 to 15 mph
winds Sunday given the pressure gradient between the building high
and offshore low. This will result in max wind chill values in the
teens and single digits.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
A cold front will move in late this morning through early this
afternoon. High pressure follows.
Lingering IFR or MVFR this morning with VFR following for the
afternoon and tonight as clouds scatter out and clear, behind
the cold front.
Winds will continue to back more SW into this morning as the
cold front approaches. Then winds back again, becoming westerly
this afternoon following the cold frontal passage. Wind speeds
will be sustained 10-15 kts this morning and into the afternoon.
There remains uncertainty regarding whether we will see gusts
this afternoon at NYC terminals. Have left out of TAFs due to
low confidence. However, for your awareness, if we see gusts
late this morning into this afternoon, it would likely be 20- 25
kts. Winds drop below 10kts this evening and become light and
variable tonight.
...NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
IFR-MVFR-VFR improvement timing may be off by a few hours.
OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
Wednesday-Wednesday night: VFR early becoming MVFR-IFR during the
afternoon with rain developing and continuing into the night. 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 day. NW gusts 20-25 kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
-- Changed Discussion --
Wind gusts have fallen below 25 kt on the non-ocean waters, so
have gone ahead and cancelled the SCA for those areas. A SCA
remains in effect for the ocean waters.
Some gusts to 25 kt will remain possible today on the ocean
waters along with lingering seas above 5 ft through the first
half of tonight. High pressure then briefly builds across the
waters tonight into Wednesday morning with sub-SCA conditions.
There are two periods in the long term forecast where SCA conditions
are possible. The first is Wednesday night into Thursday with a
low pressure system that will pass right over or near the area.
Wind gusts will be close to 25 kts, especially on the ocean waters
where seas of 5 to 6 ft are expected. The next chance for SCA
conditions will be late Friday through the weekend due to
deepening offshore low pressure. There is some uncertainty as to
how far west the low will be.-- End Changed Discussion --
&&
.HYDROLOGY...
There are no hydrologic concerns through the beginning of next
week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 1 AM EST Wednesday for ANZ350-353-
355.-- End Changed Discussion --
&&
$$
SYNOPSIS...DW
NEAR TERM...BC/DW
SHORT TERM...DW
LONG TERM...JT/DW
AVIATION...BR/JT
MARINE...JT/DW
HYDROLOGY...DW