578
FXUS61 KOKX 131722
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
122 PM EDT Mon May 13 2024

.SYNOPSIS...
High pressure will move out into the Atlantic into this A warm
front will then pass to the northeast tonight into early
Tuesday. A cold front to the west will slow down and become
nearly stationary Tuesday through Tuesday night. Low pressure
developing to the west will eventually pass to the south and
then southeast Wednesday into Wednesday night. Brief high
pressure will follow for Thursday, with several disturbances
moving through from late week into early next week.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
BKN-OVC low clouds that covered most of the area except for
eastern Long Island and much of S CT early this morning are
eroding, and now confined to mostly to the NYC metro area and
points south, and along the sea breeze boundary across Long
Island. Some of these may take until early to mid afternoon to
scatter out especially across NE NJ. These clouds will likely
limit high temps to the mid/upper 60s in NYC and NE NJ.

Southerly winds will increase this afternoon.

Some subtle small amplitude shortwaves could traverse the
interior be associated with more clouds this afternoon. For
now maintained isolated to scattered showers across mainly the
northern and eastern sections of the area late this afternoon
into this evening, as a shortwave trough rides SE through the
upper ridge. afternoon into this evening.

The ridge then shifts east into the Atlantic overnight into
early Tuesday, with negative vorticity advection and associated
subsidence/clearing skies. Low level SW flow will continue.
Radiational cooling will be partially mitigated along the
coastal areas as onshore flow and winds staying up within the
boundary layer under the eventually mostly clear sky. Used the
NBM for low tempo tonight.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
More of a SW synoptic flow sets up tonight into Tuesday with mid
level ridge moving farther east of the region and an approaching
trough from the west. At the surface, a warm front moves northeast
of the region and a trailing cold front will slow down well west of
the region. This will keep the local area in the warm sector.
Continued SW low level flow will increase 850mb temperatures
compared to the previous day so likewise surface temperatures will
also trend a few degrees warmer. Forecast highs get more in the low
to mid 70s for a greater fraction of the region.

In the mid levels, a trough will continue to approach from the west
Tuesday night into early Wednesday and will slow down as it becomes
cutoff. The cutoff mid level low slowly traverses south and
eventually southeast of Long Island Wednesday into Wednesday
night.

Upper level jet streaks move in late Tuesday into Tuesday night.
The main upper level jet thereafter stays well south of the
region late Tuesday night through midweek.

Multiple areas of low pressure are expected to form along the
front with another frontal system approaching from the south
Tuesday night into early Wednesday. The main frontal system to
the south with its center of low pressure passes south and
eventually southeast of Long Island Wednesday into Wednesday
night.

The bulk of the rain is expected Tuesday night through
Wednesday with the increase in low level omega as well as some
increased divergence aloft. Rain intensity forecast as moderate
and also expected the mode of rain will transition from
convective to more stratiform. Low pressure moving farther
southeast of Long Island late Wednesday night with decreasing
POPs for rain. Rain could be heavy at times as layer
precipitable waters increase to near 1.1 to 1.4 inches, highest
along the coast.

Regarding thunderstorms, they will be possible across western
and interior sections of the region Tuesday afternoon into Tuesday
night. This is where temperatures are forecast to be relatively
warmer, leading to more surfaced based instability. The rain will be
more of a convective mode in showers.

For temperatures, used blended guidance. Wanted to convey lower
diurnal range of temperatures Wednesday into Wednesday night,
and Wednesday daytime temperatures well below normal with the
more easterly flow.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
The area remains under an upper level trough by Thursday morning,
though it is slowly making its way east of the area during the day.
Models disagree with the speed at which the trough moves away and
thus differ on the extent of the surface low pressure`s impact on
the area. The GFS and CMC have the low far enough offshore where
there shouldn`t be much shower activity, though the ECMWF keeps the
low closer to the area allowing for continued chance of showers
during much of the day Thursday and Thursday night.

By Friday, another large scale trough brings another frontal system
into the area from the west. While the day may be mostly dry,
showers once again become possible later in the day and into Friday
evening. The upper trough moves overhead slowly through the weekend
allowing for several frontal waves and areas of low pressure to pass
by. This likely continues the chance for rain showers through the
weekend and into early next week.

Temperatures will largely be at or slightly below average for the
extended period. Each day is expected to feature highs in the upper
60s to low 70s with each night in the 50s.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Weak high pressure pushes offshore through tonight. Low pressure
slowly approaches from the southwest Tuesday into Tuesday night.

Mainly VFR. There is a chance of showers Tuesday afternoon and
early evening, especially from the NYC metro terminals on NW.

SW winds around 10 kt will shift to the S this afternoon, 10-15
kt. Any gusts 15-20 kt will be occasional and mainly located
across Long Island. S winds slowly weaken this evening and may
shift to the SSW. Wind speeds by early Tuesday morning should be
around 5 kt. SSW-S winds increase on Tuesday, becoming 10-15 kt
by late morning or early afternoon.

 ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of wind shift to the S this afternoon may be off by 1-2
hours.

A gust 15-20 kt cannot be ruled out this afternoon.

OUTLOOK FOR 18Z TUESDAY THROUGH FRIDAY...

Tuesday Afternoon: Mainly VFR. Chance of showers late. S wind
gusts 15-20kt possible near coast in afternoon.

Tuesday night: MVFR or lower in showers, most likely west of the
NYC metro.

Wednesday: MVFR or lower likely in showers. Showers diminish at
night. NE wind gusts 15-20kt.

Thursday: Mainly VFR. NE wind gusts 20 kt possible.

Friday: VFR. Slight chance of a shower late.

Saturday: MVFR possible. Chance of showers. SE gusts 15-20 kt
possible.

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

&&

.MARINE...
S flow will increase this afternoon into this evening. There is
potential for a window of 5-ft seas and 25-kt gusts on the
ocean waters S of NYC as the Ambrose Jet increases, and a short
fused SCA may become necessary from about 6-10 PM.

Otherwise, conditions should remain mostly below SCA thresholds
through Tuesday night. Wind gusts could get close at times to 25
kt over parts of the ocean, limited due to a low level
temperature inversion inhibiting mixing of stronger winds from
aloft.

Wind gusts are forecast to remain generally 15-20 kt with more E
flow developing Wednesday, and then pick up Wednesday night
with winds increasing and becoming more N. SCA wind gusts will
be possible Wednesday night especially on the ocean. From
prolonged onshore flow and fetch, ocean seas are forecast to
build to SCA levels Wednesday into Wednesday night.

Looking at the long term marine forecast period from Thursday
into the start of the weekend, lingering SCA waves on the ocean
subside by Friday with sub-SCA conditions on all waters through
Saturday.

&&

.HYDROLOGY...
No hydrologic problems expected.

&&

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

&&

$$

SYNOPSIS...JM/MW
NEAR TERM...BG/JM
SHORT TERM...JM
LONG TERM...MW
AVIATION...DS/MW
MARINE...JM/MW
HYDROLOGY...JM/MW