discussion on 2023-05-23

000
FXUS61 KOKX 231955
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
355 PM EDT Tue May 23 2023

.SYNOPSIS...
-- Changed Discussion --High pressure will be in control through tonight. A cold front
approaching from the north Wednesday will move through the region
Wednesday night. The region will be in between a cold front offshore
and an area of high pressure north of the Great Lakes Thursday. This
high pressure area will gradually move farther south and build into
the local region going into the start of the holiday weekend. The
high pressure area gradually weakens and shifts offshore towards the
end of the holiday weekend. Weak low pressure approaches for early
next week.-- End Changed Discussion --

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --High pressure centered over Atlantic Canada continues to slides
further east into the Atlantic. This will maintain and easterly
flow, but a weakened flow will result into tonight. Clear to mostly
clear skies will stick around tonight. Followed blended MOS guidance
for tonight`s temperatures to account for radiational cooling in the
Pine Barrens on LI and for some interior locations. Overnight low
temperatures in these locations may drop into the low-40s. All other
areas in the mid/upper-40s with mid-50s in the urban metro.-- End Changed Discussion --

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
-- Changed Discussion --A sharp trough in the northern branch of the jet swings southeast
from Canada Wed through Wed night, sending a surface cold front
toward and through the region.

Ahead of the approaching boundary, the persistent onshore flow will
continue to limit daytime heating along the coast, where highs
remain in the 60s. Inland however, a mild SW flow likely allows
parts of NE NJ and the Lower Hudson Valley to achieve the upper 70s
to near 80 in far northern or western spots of the CWA.

A uniform line of showers with isolated thunderstorms along the cold
front is expected to enter northern portions of the Lower Hudson
Valley around late afternoon/early evening on Wednesday. Isolated
thunderstorm chances were kept mostly to Orange county as the
already marginal instability drops as the front drops south.
The line of precip will fall apart as it approaches the city and
CT. Some low 20-30 POPs were still kept for the city and
western LI and SW CT, but the showers will fizzle out as they
track further east, with no QPF expected east of the city or
east of SW CT. QPF will likely be around 0.25" in in Orange and
Putnam counties, dropping to only 0.01" by the time the line of
precip reaches the city. Its very likely coastal locations
remain completely dry, though a few drops in the dissipating
line can still be expected.

Conditions dry out Wednesday night behind the front, with a 1030 mb
high building in from the northwest once again. Blustery conditions
develop after the front into Thursday morning with a tightening
pressure gradient as the high builds, generally gusts 20-25 mph.
Went with a blended short term model consensus for winds overnight
Wednesday into Thursday morning.-- End Changed Discussion --

.LONG TERM /THURSDAY THROUGH TUESDAY/...
-- Changed Discussion --In the upper levels, trough base near the local area early Thursday
morning. An upper level jet streak intensifies southeast of Long
Island with WSW to ENE orientation Thursday into Friday.

Then, the local area will be in between an upper level trough to the
northeast and a large closed off upper level low to the southwest.
There will be some ridging in between these two features that will
encompass the local area going into the holiday weekend. Mid level
negative vorticity advection is expected Friday through Sunday.

At the surface, high pressure will gradually build in from north of
the Great Lakes Thursday into the holiday weekend. Aloft, with some
cyclonic flow Thursday into Thursday night, increased cloud coverage
especially during the day and into early evening. More subsidence
expected Friday through Sunday with the center of high pressure
getting closer to the area.

Went more with a MAV MOS and NBM blend for lows Thursday night into
early Friday morning, with more radiational cooling and the MOS
conveying a more vast range of low temperatures.

Models convey the mid level ridge to weaken as well as surface high
pressure for Sunday into Memorial Day with high pressure shifting
more offshore. Forecast has slight chance POPs for rain showers
Sunday afternoon through Sunday night as well as Memorial Day. With
POPs just being slight chance, mainly dry conditions are anticipated
with coverage of showers just isolated.

The GFS, ECMWF, and Canadian models all depict no precipitation from
coastal New England south through DelMarva for Friday through Sunday
night with drier trends comparing 12Z runs to 00Z runs. The 12Z runs
of the ECMWF and Canadian models start to indicate more
precipitation for Memorial Day itself developing in different parts
of the region as the ridging breaks down more. POPs increase to
chance for rain showers Monday night and into next Tuesday.

Temperatures in the long term overall forecast to be below normal
Thursday and Thursday night. Temperatures trend closer to normal
Friday into Saturday. Daytime temperatures thereafter forecast to
grow above normal with forecast highs getting to mainly a mid 70s to
near 80 range for Memorial Day and Tuesday next week.-- End Changed Discussion --

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --High pressure will remain in control through Wednesday morning.
A cold front approaches from the north Wednesday afternoon.

SE winds 10-13 kt this afternoon. Winds gradually diminish this
evening and then become light and variable overnight. Winds will
become S-SE middle to late Wednesday morning and increase into the
afternoon around 10 kt. The flow should become SW at KSWF ahead of
the approaching cold front Wednesday afternoon.

Mainly VFR. Included a PROB30 for showers Wednesday evening in the
30 hour TAFS (KJFK, KLGA, KEWR, and KSWF).

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

Wind speeds could end up a few kt higher than forecast into early
this evening.

OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...

Wednesday PM: Mainly VFR. A chance of showers during the late
afternoon and early evening, mainly from NYC on NW. A slight chance
of thunder near KSWF in evening. S-SW winds shifting to N at night
and gusting 20-25 kt.

Thursday-Friday: VFR. N wind G20-25 kt Thursday morning.

Saturday-Sunday: VFR. A slight chance of showers on Sunday near the
coast.

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

.MARINE...
-- Changed Discussion --Conditions will remain below SCA through Wednesday afternoon.
Wednesday night into Thursday morning SCA conditions are expected
along and after a cold front with winds gusting at or slightly above
25 kts over ocean waters and waves at 5 ft. There are forecast
to be residual SCA conditions on the ocean Thursday morning and
perhaps into Thursday afternoon, but the trend will be that of
lessening winds and waves. Mainly below SCA conditions are
expected Thursday afternoon. All waters are forecast to remain
below SCA thresholds Thursday night through Sunday night with
the pressure gradient remaining relatively weak magnitude
overall.-- End Changed Discussion --

.HYDROLOGY...
-- Changed Discussion --
There are no hydrologic concerns through early next week.-- End Changed Discussion --

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 11 PM Wednesday to 11 AM EDT
Thursday for ANZ350-353-355.-- End Changed Discussion --

$$
SYNOPSIS...JM/BR
NEAR TERM...BR
SHORT TERM...BR
LONG TERM...JM
AVIATION...DS
MARINE...JM/BR
HYDROLOGY...JM/BR