discussion on 2023-05-23

000
FXUS61 KOKX 232338
AFDOKX

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

.SYNOPSIS...
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.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --Increased clouds this evening, mainly across the western parts
of the local region. Hourly dewpoints were lowered along parts
of the coast this evening. Otherwise, forecast is on track.

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. Clouds
expected to diminish in coverage later 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/...
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.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
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.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --High pressure will remain in control through Wednesday morning.
A cold front approaches from the north Wednesday afternoon and
passes through by Wednesday evening.

Any SE winds around 10 kt this evening diminish 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. Winds shift to NW then N behind
the cold frontal passage with winds increasing into the evening
and overnight.

Mainly VFR. Included a PROB30 for showers Wednesday evening for all
TAF sites. KSWF likely sees showers with a PROB30 for TSRA Wednesday
afternoon into the evening.

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

Timing of wind shift with cold frontal passage may be off +/- 1-2
hours.

OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...

Wednesday Night: 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...
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.

&&

.HYDROLOGY...
There are no hydrologic concerns through early next week.

&&

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

&&

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