533
FXUS61 KOKX 122357
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
657 PM EST Thu Dec 12 2024
.SYNOPSIS...
High pressure will gradually build into the region and
strengthen through Friday night. Strong high pressure remains
over the region for Saturday. High pressure over the region
Saturday night retreats off the New England coast late in the
weekend followed by a weak disturbance to begin the work week.
Another disturbance in the form of a warm front, followed by a
cold front moves across Monday night into Tuesday. Weak high
pressure builds across for mid week. Another disturbance may
approach for Thursday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Much colder tonight into early Friday morning with a very cold
airmass settling into the region. Forecast lows range from mid teens
to mid 20s overnight into very early Friday. Minimum wind chills
reach into the single digits and lower teens for the same timeframe.
Westerly flow aloft remains for tonight with a tight height
gradient. Trough will be slowly shifting north. Jet streak maxima
moves across. At the surface tonight, a gradual decrease in pressure
gradient is forecast between strong low pressure in Eastern Canada
and strong high pressure to the west. Winds are expected to
decrease. Gusts up to near 25 to 30 mph into this evening should
diminish more overnight.
For the min temperatures forecast tonight, used a MAV/MET/NBM blend.
The boundary layer mixing is more in the first half of the night and
the winds do not totally decouple and become calm so did not take
coldest of the MOS with the forecast. Range of lows forecast mid
teens to mid 20s.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
Expecting dry weather, less gusty winds, and a very cold airmass
with much below normal temperatures Friday through Saturday.
Efficient radiational cooling expected Friday night into
Saturday morning. Mostly clear sky conditions expected through
this forecast period.
Core of cold airmass moves in Friday into Friday night with
850mb temperatures in -10 to -15 degrees C range. Forecast high
temperatures don`t get out of the 30s for Friday and Saturday.
Lows Friday night range from near 10 to lower 20s. Overall,
forecast highs around 10 degrees below normal and forecast lows
near 10 to 15 degrees below normal.
For Friday through Saturday, there will be a gradual weakening of
the height gradient aloft. A trough over the Northeast slowly
shifts farther north of the region with gradually rising
heights. The upper level jet streak remains over the area Friday
and then exits east of the area as well as weakens Friday
night. Northwesterly flow aloft Saturday. Main jet streak
continues moving east out into Atlantic Saturday.
At the surface, for Friday, strong high pressure continues to
approach from the west with its center within the Great Lakes
vicinity. For Friday night, the center of the high gets
stronger and moves farther into the Northeast. The center is
still expected to be west of the region Friday night into early
Saturday morning, more within the NE PA to Central NY state
region. For Saturday, the center of the high moves farther
north, eventually reaching near SE Canada with its axis moving
into the local region.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
High pressure will settle over the region Saturday night. With clear
skies and a light to calm winds and a cP air mass still in place
look for a good radiational cooling set up. Temperatures will be
allowed to drop into the teens across northern and rural locations.
A few locations perhaps getting to around 10 for a low Sunday
morning across far NW portions of Orange County, otherwise mainly
20s closer to the coast. The high will push offshore later Sunday
into Sunday night. The day Sunday will be dry, but with an increase
in upper and mid level clouds. Dewpoints will gradually rise through
the day with retreating high pressure moving off the New England
coast as an onshore wind develops out of the east. Temperatures
therefore moderate some, especially closer to the coast where 40s
take place, otherwise upper 30s inland.
For Sunday night look for cloudy conditions as a system which
weakens aloft approaches. Guidance is suggestive of enough thermal
advection to bring light precip into the area. The retreating high
will leave some low level cold air around initially late Sun night
into early Mon AM. Look for light precipitation to break out during
the overnight / early Monday AM for western sections where it may
begin as a little light snow / wintry mix. Any leftover cold air
will continue to retreat into Monday so look for mainly light rain
closer to the coast and for the city, and any wintry mix going over
to rain further inland. Temperatures should warm into the lower 50s
across southern coastal locations, to the lower 40s well north and
west. Another disturbance associated with a more potent shortwave
and a warm front is expected to move in quickly behind the first
disturbance. Therefore, look for another round of mainly light
precipitation Monday night into a good portion of Tuesday. Dew
points at this juncture should get into the 40s across most of the
area so p-type will be liquid once again. The cold front associated
with the second system swings through either later in the day
Tuesday or by early Tuesday evening. This will lead to drier air
arriving with some partial clearing into Tuesday night. Weak high
pressure should then settle over the area on Wednesday. There won`t
be much in terms of colder air behind the cold front as temperatures
on Wednesday will average a touch above normal with mainly middle
and upper 40s.
Another fast moving disturbance over the nation`s midsection will
attempt to approach on Thursday, but may arrive as early as
Wednesday night. There is a good amount of model disagreement on the
speed of this system. With a lack of cold air out in front of it
look for mainly a chance of rain Thursday, with perhaps a brief
wintry mix across far NW portions of the region as temperatures
should top out mainly in the 40s.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
High pressure builds eastward from the Plains states into
southeastern Canada and New England.
VFR through the TAF period.
W winds around 10 or less for most terminals, except 10 to 15 kt
for KJFK and KLGA with gusts 20 to 25 kt through about 02Z.
Winds are expected to diminish for all terminals overnight.
Winds increase Friday with gusts 15 to around 20 kt by midday
before diminishing again by late afternoon. Some shifting of
the wind possible Friday afternoon to more northwesterly.
...NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
No unscheduled AMD expected. Gusts to 20 kt (isolated to 25 kt)
possible through 02Z for all terminals, but most likely for
KJFK and KLGA.
OUTLOOK FOR 00Z FRIDAY THROUGH TUESDAY...
Friday Night: VFR.
Saturday: VFR.
Sunday: BKN MVFR cigs possible along the coast in the afternoon.
Sunday night: Chance of MFR or lower conditions mainly after
midnight. Precip type snow at KSWF, a rain/snow/sleet mix at
KHPN/KBDR/KGON, and mainly rain at the NYC metros/KISP.
Monday: MVFR cond possible in light rain. Wintry mix possible at
KSWF early.
Tuesday...IFR or lower possible in a chance of rain.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Gales have diminished across the waters but still could have an
occasional gust to 35 kt into early this evening. SCA on all
waters through this evening. Overnight, ocean has SCA with sub-
SCA conditions on non-ocean waters. For Friday, SCA remains east
of Fire Island Inlet on ocean with otherwise sub-SCA conditions
on rest of waters. Friday afternoon through Saturday, sub-SCA
conditions expected with high pressure moving in. Ocean seas
elevated near 6 to 12 ft into tonight.
The 5 ft seas on ocean linger into Friday mostly east of Fire
Island Inlet. The 5 ft seas on ocean Sandy Hook NJ to Fire
Island Inlet NY could linger into Friday morning but confidence
is low on that.
Sub small craft conditions take place Saturday night into Sunday.
However, seas will begin to gradually increase on the ocean during
the day Sunday into Sunday night. By Monday expect some 5 ft seas on
the ocean waters with marginal small craft conditions by the
afternoon. Small craft conditions should be in place on the ocean
Monday night into Tuesday. A southerly flow increases as gusts
approach small craft criteria during the day Tuesday.
&&
.HYDROLOGY...
Dry conditions forecast through Saturday.
There are no hydrologic impact threats through the middle of
next week.
&&
.CLIMATE...
For Saturday for the local region, the potential high sea level
pressure (SLP) is close to the highest observed across the
northeast in December and in any month based on data from WPC.
The highest observed SLP in the northeast ranges from 1052-1054
mb, which occurred on February 13, 1981. The highest observed
SLP at Central Park was 1052.5 mb, which also occurred on
February 13, 1981. The highest observed SLP in the northeast for
December ranges from around 1049-1053 mb (1051.8 mb at Central
Park), which occurred on December 25, 1949.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until midnight EST tonight for ANZ331-332-
335-338-340-345.
Small Craft Advisory until noon EST Friday for ANZ350-353.
Small Craft Advisory until 6 AM EST Friday for ANZ355.
&&
$$
SYNOPSIS...JE/JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...JE
AVIATION...JP
MARINE...JE/JM
HYDROLOGY...JE/JM
CLIMATE...