discussion on 2023-11-30

000
FXUS61 KOKX 010240
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
940 PM EST Thu Nov 30 2023

.SYNOPSIS...
High pressure off the southeastern coast will remain in control
through tonight and into early Friday. A weak wave of low pressure
then passes slowly through the region late Friday through Friday
night. A weak wave of low pressure moves across Saturday night,
followed by another weak low being nearby later Sunday and
Sunday night. A weak trough moves through on Monday. A clipper
low moves south and offshore for mid week, followed by high
pressure nosing in from the southwest for late in the week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
-- Changed Discussion --The fcst is on track. Near zonal upper flow will remain through
tonight as a dampening southern stream shortwave moves toward
the Ohio Valley. At the surface, high pressure off the
southeastern states will remain in place. A return flow will
remain tonight with falling temperatures leveling off as upper
level clouds and warm advection increase. Low temps a bit above
seasonal normals for the first day of meteorological winter,
December 1.-- End Changed Discussion --

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
The weak upper shortwave moving through the near zonal flow
continues to weaken and flatten Friday and shears out into a
broad flat wave by 12Z Saturday with the wave east of the Great
Lakes and into upstate New York. Lift will be weak, but
increasing later Friday as warm advection strengthens with
increasing isentropic lift. Also, a low level jet streak will
enhance lift later Friday into Friday night. The timing for the
onset of precipitation is slightly later than previous
forecasts, with the rain arriving in the western and northern
area mid to late Friday afternoon. There may be enough cold air
in place at the onset of precipitation for a few flurries
across the higher terrain of Orange County. Much of the energy
with the upper wave tracks to the north of the region, and with
the flat flow the system will remain progressive. Precipitation
will be mainly occurring Friday night, ending late Friday and
toward Saturday morning. With mid level drying and the lower
levels remaining saturated, especially toward the coast, a
period of light rain and drizzle will be possible.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
A complicated pattern in the long term with a series of waves
of low pressure to monitor.

To begin the period ridging off the SE coast and into
Hispaniola will have temperatures starting off milder overall.
Temperatures should get well into the 50s to start the weekend
on Saturday despite a good deal of clouds in advance of weak low
pressure moving quickly from SW to NE. Mainly just some thermal
forcing with this system. Vertical motion will be fairly weak
with a lack of strong advection both in terms of temperature and
vorticity. The system will be rather progressive, therefore
look for a plain light rain with milder air preceding the
system. The most likely period of measurable rain for the
weekend is Sat night with the first wave, followed by another
brief period of high end chance / low end likely PoPs for late
in the day Sunday and Sunday night more associated with the main
trough pivoting through. Rainfall amounts summed from both
waves of low pressure should not amount to more than a quarter
to a half inch. Thus, likely under a quarter of an inch from
both disturbances.

As the low associated with the upper levels begins to deepen as
it pushes away on Monday a NW flow will increase. This will
usher in on a NW flow another round of seasonably cold air. By
late Monday night and into Tuesday temperatures will fall to
normal levels, or perhaps a degree or two below normal. By
Tuesday a clipper type low is expected to drive SE across the
Eastern Plains and Midwest. The GFS is the least progressive
with this system and actually has some semblance of it more
amplitude to it compared to the other global guidance camps. The
ECMWF is the most progressive with this spoke of energy and
pushes the system just south of the area and well offshore. If
the GFS deterministic solution is close to being correct then a
touch of light snow would be possible Tuesday night into early
Wed. The consensus of the guidance was followed and stayed close
to the NBM PoPs. Have slight chance PoPs in case system does
attempt to be less progressive as there is some semblance of a
positive height anomaly in Davis Strait / Greenland and a 50/50
low. The gut feeling at this point is the system should be
progressive enough with most of the precip likely staying off
shore into early Wed.

High pressure is then progged to nose in from the southwest for
later in the week. A milder SW flow may return towards the end of
next week. Overall temperatures should average near to slightly
below normal Tuesday through Thursday.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --VFR as high pressure remains to the south. SW winds mainly blw
10 kt overnight. Fri will be VFR before a ceilings drop to
MVFR aft 20Z. Pockets of IFR possible especially aft 00Z. SW/SSW
winds around 10 kt.

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

No unscheduled amendments expected.

OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...

Friday night: Rain with MVFR or lower cond.

Saturday: Chance of light rain or drizzle, with MVFR or lower cond
possible.

Sunday: Rain with MVFR or lower cond likely. N winds G15-20kt NYC
metro/coast late at night.

Monday: Chance of rain. MVFR or lower cond likely especially AM.
NW winds G20kt.

Tuesday: Chance of rain early, VFR by the afternoon. NW winds G20kt.

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

&&

.MARINE...
As high pressure moves farther off shore of the southeastern coast
and a cold front approaches from the northwest into this evening,
the pressure gradient increases slightly and southwest wind gusts
and ocean seas may approach SCA levels. The pressure gradient then
weakens late tonight into Friday as a southern stream low moves into
the Upper Midwest and central Mississippi Valley. A SCA for the
ocean waters will remain in place through tonight for the marginal
conditions. With conditions likely falling below advisory levels
Friday morning, have cancelled the advisory for the eastern waters
that was in effect Friday morning. Then with the low weakening
gradually and moving into the region late Friday into Friday night,
winds and seas on the ocean will remain below advisory levels through
Friday night.

For the non ocean waters winds and seas remain below advisory levels
tonight through Friday night.

Sub small craft conditions are expected through much of the weekend.
Late Sunday night and into Monday and Monday night in the wake of
low pressure small craft conditions will become increasingly likely
on the ocean waters. During the day on Monday and also into much of
Monday night on a NW wind there will also be the possibility of small
craft conditions on the near shore waters due to gusts around 25 kt.
Sub small craft conditions would then likely return for all waters
on Tuesday.

&&

.HYDROLOGY...
There are no hydrologic concerns through next Thursday.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EST Friday for ANZ350-353-355.

&&

$$