Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 141824
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
224 PM EDT Sun Apr 14 2024

.SYNOPSIS...
Weak high pressure over the area this morning slides east, giving
way to a quick moving low pressure system approaching from the
Great Lakes. The low will pass to the north this evening and drag
a cold front across the area. High pressure returns for the first
half of the week. A slow moving warm front then approaches from
the southwest Wednesday night into Thursday, followed by a cold
front late in the week as low pressure passes well to the
northwest.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Showers are moving through in association with the weakening
complex of showers and thunderstorms earlier this morning across
upstate NY and northern PA. These showers have continued to
weaken over the area. However, more showers have developed
across the Mid Hudson Valley ahead of the warm front moving
southeast. These storms should continue to weaken as they make
their way into more stable, however a stray thunderstorm may
makes its way into the Lower Hudson Valley and southeastern CT
after 18Z.

Otherwise, jet energy passing across the Great Lakes region
today will send low pressure to the north of the area this
evening, dragging a cold front through the area. It will be
preceded by a warm front this afternoon, but the cold front will
be the main focus of attention as a line of showers and
thunderstorms develops along it and moves into the area toward
evening. There is the potential for a few strong and/or severe
thunderstorms with the main threat being strong to damaging wind
gusts. SPC has placed portions of the forecast under a Marginal
and Slight Risk. However, the main threat will be primarily
north and west of NYC.

While there is deep-layer shear present with strong mid-level
flow, instability is generally weak and confined primarily to
the mid levels. Surface-based CAPE is located mainly north and
west of the NYC metro with SPC HREF max CAPE values of 500-1000
J/KG. Mean CAPE values are less than 250 J/KG. This is partly
due to the frontal timing in the evening after max insolation,
but also dry air in the low-levels. CAMs generally show the line
dissipating this evening as it approaches the area and in some
cases with no more than a spotty shower reaching the coast. So
the best chance will be across the interior with chances
decreasing toward the coast.

Much of today though will be dry and warm with highs in the
upper 50s to lowers 60s along the coast, and around 70 from NYC
and points north and west. A few warm advection showers can`t be
ruled out this afternoon with a period of mid and high level
cloudiness moving through. West winds this morning will veer
around to the SW-S this afternoon, ramping up with wind gusts of
25 to 30 mph. Coastal locations will see temps peak late
morning/early afternoon before southerly winds bring cooler
maritime air to the coast, especially along the oceanfront and
twin forks of LI.

The cold front passes south of LI during the early morning
hours Monday with clearing skies. Lows will remain above normal
in the upper 40s to mid 50s, warmest across the NYC/NJ metro.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
The amplifying upper trough across eastern Canada during this
time will allow for some weak cold advection to continue on
Monday, albeit still well above normal. Monday will be the
warmest day with even coastal locations getting in on the
action with highs well into the 60s. The NYC/NJ metro is
expected to get into the lower 70s. Highs drop a few degrees on
Tuesday, but remaining above normal. During this time, ridging
over the mid section of the builds east and conditions are
expected to be dry and sunny.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
*Key Messages*

*Unsettled conditions from mid to late week with daily shower
chances from late Wednesday on.

*Normal to slightly above normal temperatures midweek into next
weekend.

Not much change in the forecast thinking for the period. The NBM was
followed for this update with some minor changes to PoPs and thunder
for Thursday. The global ensemble means continue to be in consistent
agreement with synoptic scale ridging deamplifying to a more zonal
flow by the end of the workweek and into next weekend.

Mainly dry weather is expected through Wednesday AM, though clouds
will be on the increase as a warm front attached to a deepening sfc
low across the upper midwest approaches from the southwest. Shower
chances increase through Wednesday late afternoon and into the
evening as the front slowly moves north. While PWATS look to be near
1.25" per latest model soundings (near the daily max via SPC
sounding climo for OKX), better forcing remains back to the west, so
expecting mainly light rain event at this point, with NBM showing
less than 0.5" areawide though Thursday evening. Latest global
ensemble guidance indicating that the area may not be as warm
sectored as previous guidance indicated, with the warm front
remaining over or just south of the area. That would limit any
convective potential, and so have maintained previous forecast
without mention of thunder Thursday afternoon and evening, for now.

Friday remains unsettled as another quick moving frontal system
impacts the area, with shower chances remaining especially in the
afternoon into early Friday.

Temperatures will remain near to slightly above normal for much of
the week.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A warm front moves north of the region this afternoon followed
by a cold front moving in tonight. This cold front weakens
across the area and slides south of the area late tonight into
Monday.

One round of rain showers is moving across this afternoon,
passing across CT terminals and KISP. Then, a second round of
showers and thunderstorms develops and moves in this evening,
probably as a broken line of rain showers and thunderstorms.
Brief gusty strong winds and MVFR will be possible with these
thunderstorms this evening with higher chances at KSWF. Timing
of showers and thunderstorms mainly in a 0-4Z timeframe.
Otherwise, VFR continues and is expected to hold on through the
remainder of the TAF period.

Winds will be increasing S-SW near 15 to 20 kt with gusts near
25-30 kt along the coast with lower winds farther inland. Winds
become more NW late tonight and decrease to near 5-10 kt. Winds
return back to a more westerly flow Monday late morning into the
afternoon with wind speeds around 10 kts.

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

Timing of TSRA and MVFR may be off by +/- 1 to 3 hours.

Occasional higher gusts around 35 kt possible for NYC terminals
this afternoon through this evening.

Showers and thunderstorms may weaken and dissipate upon arrival
this evening.

OUTLOOK FOR 18Z MONDAY THROUGH THURSDAY...

Mon: VFR. W-NW gusts 15-20 kt in the afternoon into early evening.

Mon night through Tue: Mainly VFR.

Wed and Thu: MVFR or lower possible at times with potential for
rain showers, most likely in the Wed night into early Thu time
period. Easterly winds near 10-15 kt with gusts near 20 kt late Wed
night into Thu.

Fri: Chance of rain showers and MVFR.

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

&&

.MARINE...
A SCA is in effect for the ocean waters into Monday, and for NY
Harbor, the South Shore Bays, and the western sound into this
evening.

An approaching frontal system today will result in west winds
backing around to the S-SW and ramping up to SCA criteria with
even a few gusts on the ocean approaching gale force. Seas on
the ocean build to 5 to 9 ft by this evening. Winds will then
begin to gradually weaken this evening as a cold front works
across the area and south of the waters by early Monday
morning. SCA seas will linger on the ocean into Monday.

Thereafter, Sub small craft conditions are likely on all waters
through Wednesday. SCA conditions may then return to the ocean
waters on Thursday as a frontal system approaches.

&&

.HYDROLOGY...
There are no hydrologic concerns thought the forecast period.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ335.
     Small Craft Advisory until midnight EDT tonight for ANZ338-345.
     Small Craft Advisory until 2 PM EDT Monday for ANZ350-353-355.

&&

$$

SYNOPSIS...DBR/DW
NEAR TERM...JP/DW
SHORT TERM...DW
LONG TERM...DBR
AVIATION...JM
MARINE...DBR/DW
HYDROLOGY...DBR/DW


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