318 
FXUS61 KOKX 201655
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1155 AM EST Tue Feb 20 2024

.SYNOPSIS...
Canadian high pressure remains in control through Wednesday, 
then weakens into Thursday. Low pressure approaches Thursday 
night and passes through on Friday. High pressure follows for 
the weekend, then a warm front passes through Sunday night, 
which will be quickly followed by a weak cold front.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
The forecast is mainly on track this afternoon. The biggest 
adjustment was to lower dewpoints a bit. The NBM 10th percentile
was blended in through the the early evening to capture the
current trend. 

In the upper-levels, we start today with a long-wave trough and
polar jet situated to our north which will slide east of the 
Canadian Maritimes tonight leaving us with weak upper-level 
zonal flow on Wednesday. At the same time, a deepening shortwave
slides east across the SE US and offshore by midweek (with a 
weak southern low shearing north towards the region).

At the surface, Canadian high pressure slides east across the NE US 
on Tuesday and then slowly drifts east of the Canadian maritimes 
Tuesday night thru Wednesday night, while nosing back SW across the 
region. Meanwhile, an offshore low develops in response to the 
shortwave over the Gulf Stream and slowly drifts NE (NW of Bermuda) 
through mid week.

Dry conditions prevail thru the period with a continental polar 
airmass Tuesday transitioning to a Canadian maritime airmass thru 
midweek as the high shift northeast of us. Scattered cloud cover 
appears likely to develop on Wednesday with onshore flow and nearby 
low pressure offshore.

Temps will run several degrees below seasonable on Tuesday under the 
southern periphery of the polar high with highs in the mid-30s. 
Temperature will moderate closer towards seasonable on Wednesday 
with maritime NE flow with highs near 40 degrees. Overnight Tuesday
temperatures under clear skies and light winds will drop into 
the teens to 20s for most, near 30 for the NYC metro.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
High pressure will gradually weaken Wednesday night and further lose 
hold on Thursday as a frontal system approaches from the west. Cloud 
cover will increase to broken then overcast west to east across the 
area Thursday from the approaching system. Partly cloudy skies will 
keep temperatures warmer Wednesday night with lows in the mid-20s 
for most. Low-30s in the NYC metro. Highs on Wednesday will warm 
into the low/mid-40s as warmer air surges in from southerly winds 
ahead of the approaching frontal system. Things should stay dry 
until Thursday evening/night.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A digging 500mb trough approaches from the west Thursday night. This 
will help push a developing area of surface low pressure through the 
forecast area during Friday. PoPs ramp up to likely late at night 
into Friday morning with rain likely ending everywhere by the end of 
the afternoon. Thermal profiles aloft are just cold enough to 
support a mix of rain and snow should any precip fall before around 
midnight across the northernmost zones. Temps aloft warm up 
thereafter, and with a southerly flow, surface temps should remain 
above freezing. High temperatures Friday 45-50.

Breezy for Friday night into Saturday as high pressure builds in 
behind the departing storm which will be strengthening as it moves 
through the Canadian maritimes. Colder, with highs on Saturday below 
normal in the lower and middle 30s. The high pressure ridge shifts 
through on Sunday with lighter winds and milder daytime temperatures.

A warm front approaches Sunday night. Moisture and lift with the 
front may be just enough for some light precipitation, which would 
be mainly rain with the exception of a wintry mix across the 
northernmost zones during the evening hours before temperatures 
aloft warm up behind the warm front. Kept PoPs at slight chance for 
Sunday night. Weak high pressure keeps us dry on Monday with highs 
above normal.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
VFR with high pressure in control. 

NE winds becoming ENE after the morning push, then SE this 
afternoon, remaining under 10kt. Winds throughout the day may
become light and variable at times at any terminal. Winds shift
toward the east tonight, still under 10 kt.


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

Timing of wind shifts in the TAF may be off by 1-2 hours.

OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...

Wednesday: VFR. Low chance for MVFR stratus near the coast in the 
morning.

Thursday: VFR. 

Thursday night and Friday: MVFR or lower cond beginning mainly at 
night, with rain becoming likely, possibly beginning as a wintry mix 
at the onset at or near KSWF.

Friday night: VFR. NW winds G15-20kt.

Saturday: VFR. NW winds G20-25kt.

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

&&

.MARINE...
Sub-SCA conditions expected through Wednesday under influence 
of high pressure. ESE ocean swells emanating from large offshore
low will build to SCA levels on the ocean waters Wednesday 
Night and remaining into Thursday.

SCA conds continue on the ocean waters through Saturday night, 
primarily due to swell, but gusts over 25kt are expected Friday 
night into Saturday behind the passage of low pressure and a cold 
front. This will bring advisory conditions to the non-ocean waters 
as well during this period.

&&

.HYDROLOGY...
There are no hydrologic concerns through the beginning of next
week.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$

SYNOPSIS...JC/BR
NEAR TERM...BR/JT
SHORT TERM...BR
LONG TERM...JC
AVIATION...JC/JP
MARINE...JC/BR
HYDROLOGY...JC/BR