okx-afd on 2025-03-31

120
FXUS61 KOKX 311423
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1023 AM EDT Mon Mar 31 2025

.SYNOPSIS...
-- Changed Discussion --A warm front lifts north of the area this morning. Low pressure
passing through southern Quebec will drag a cold front toward
the area late today into tonight. High pressure will ten builds
southeast toward the area Tuesday into Tuesday night, and pass
east on Wednesday. A warm front will approach Wednesday night
and move across early Thursday. A cold front will then approach,
moving across Thursday night. The front will slow down to the
south Friday, eventually returning back north into the area for
the weekend.-- End Changed Discussion --

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --Warm front remains south of Newark but was through LaGuardia
and most of southwestern Connecticut. North of the front patchy
dense fog remains along with widespread fog of 1/2 to 2 miles
visibility. The Dense Fog Advisory was allowed to expire.

Have updated temps go go warmer mainly west of the Hudson based
on latest LAMP/HRRR guidance, with highs in the lower/mid 70s
now expected for areas from NYC north/west. Elsewhere a gusty S
flow should help temps warm up into the 60s.

In the overall warm advection well ahead of the front skies
should remain mostly cloudy and there could be sct showers at
any time especially by this afternoon. Air mass destabilizes
this afternoon especially across from interior northern NJ and
points SW, with tstms possible, some of which could produce
locally damaging wind gusts and some hail. Air mass looks more
primed just west of the CWA. The slight risk was extended
eastward and encompasses northeastern New Jersey, the Lower
Hudson Valley, New York City and Nassau county, along with
portions of Fairfield county, and far western Suffolk county.

NSSL CAM`s show cluster of storms moving from northern NJ and
parts of the lower Hudson Valley toward the NYC metro area and
SW CT late today into early this evening. East of there more
marine influence via S flow should lessen the svr threat, though
there should be enough elevated instability and lift ahead of
the front for widespread moderate to locally heavy showers and
chance of tstms anywhere in the CWA going into tonight.

Cold front passes through mainly late tonight, with gusty NW
flow in its wake and precip ending from W to E. Low temps
tonight will be in the 40s.-- End Changed Discussion --

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
Post-frontal N-NNW flow ushers in a dry and cooler air mass,
with highs 55-60 on Tue. Mostly clear skies and light winds will
promote radiational cooling Tue night as the high builds over
the area, with low temps ranging from the mid 30s in NYC to
below freezing in most spots outside the metro area, getting as
low as the mid 20s well inland.

Wed will remain on the cooler side, with a developing onshore
flow as the high passes east, and high temps only reaching 50 in
NYC/NE NJ and the mid/upper 40s to the north/east. An
approaching frontal system may bring its first chance of showers
to area well NW of NYC in the afternoon.

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Periodic slight undulations in otherwise a mainly zonal flow for
the mid levels. These undulations move across the local area
Thursday through the weekend. These indicate smaller wavelength
shortwaves within the mid levels that will help provide vertical
synoptic lift.

Wednesday night, mid level ridge axis across the area with
surface high pressure moving farther east of the region, out
into the Northern Atlantic. A warm front moves through with
chances of rain showers across the region. Mid 30s to lower 40s
for forecast lows Wednesday night. Boundary layer expected to be
just warm enough across the interior to keep this precipitation
event all rain.

Mid levels show a few shortwaves moving across with areas of
positive vorticity advection. Much of the energy though is
displaced well north of the area. Airmass becomes within warm
sector Thursday and then a weakening cold front moves across
Thursday night, slowing down as it moves through. Chances of
rain showers continue.

The front eventually moves far enough south of the region Friday
into early Saturday to allow for mainly dry conditions. POPs for
showers significantly lowers during this timeframe. However,
next system approaching from the west and its subsequent
evolution will allow for the return northward of this front as a
warm front for Saturday afternoon. Mid levels show an increase
in shortwave activity for Saturday into Sunday. The forecast
does not have much progress with the front for remainder of the
weekend. Therefore, rain showers chances in the forecast remain
through the remainder of the weekend.

Regarding temperatures, the long term period starts the
moderation of the airmass with lows trending warmer Wednesday
night compared to the previous night. This will be followed by
forecast highs Thursday that will be much warmer than those of
the previous day. Mild above normal temperature continue
Thursday night and Friday before trending back down Friday night
and Saturday, getting closer to normal values. Temperatures
forecast thereafter shows a slight trend downward for lows
Saturday night and a slight trend upward for highs on Sunday.

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A warm front eventually moves across the terminals through this
morning. This will be followed by a cold front for tonight.

Mainly LIFR to localized VLIFR conditions are expected this
morning. The increase in winds is expected to slightly improve
conditions for this morning, but still expect mainly LIFR to IFR
conditions. Most visibilities this morning are expected to be
more IFR to MVFR with the increased wind. Further improvement to
MVFR expected for the afternoon into evening for most terminals
except for CT terminals and KISP, which are expected to
maintain at best IFR conditions.

Showers will not have much coverage to start going into this
morning but do expect the shower coverage to increase from west
to east by mid to late this afternoon. Showers are expected for
all terminals for the first half of tonight and for NYC
terminals as well as terminals to the north and west, there is a
chance of thunderstorms around 22Z to 03Z.

Post cold front tonight, improvement to MVFR expected for all
terminals with some rain showers lingering around. Further
improvement to VFR expected towards daybreak Tuesday with rain
showers tapering off.

Winds initially variable for most terminals at or less than 5
kts, eventually becoming more southerly near 5-10 kt. S-SW winds
increase late this morning into this afternoon to near 12-15 kt
with gusts 20-25 kt. Winds eventually transition to NW after the
cold front tonight.

Low level jet already in place with SW winds of 40-50 kt at
2kft. This low level wind shear is forecast to persist for the
rest of this morning into early this afternoon. Low level jet
expected to last through today and this evening at KGON. Other
more southern coastal terminals also get a return of the low
level jet this evening. The evening low level jet will be
similar magnitude and direction as the morning low level jet.

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

Amendments likely to refine timing of categorical changes as
well as timing of thunderstorms.

Amendments likely to refine timing of SW to NW wind direction
changes such as with the cold front.

IFR possible at times this afternoon into this evening.

Thunderstorms in the 22Z-03Z time window could have strong gusty
winds and hail.

.OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY...

Tuesday: MVFR possible early with low chance of rain showers
east of NYC terminals. Otherwise VFR. NW wind gusts around
20-25 kt during the day.

Wednesday: Mainly VFR during most of the day. MVFR or lower
possible late afternoon and at night with a chance of showers.
SE wind gusts 15-20 kt afternoon into evening.

Thursday: MVFR or lower possible with a chance of showers,
eventually becoming likely at night. SW wind gusts 15-20kt,
highest along the coast day into evening.

Friday: MVFR or lower possible early with a chance of showers.
Mainly VFR afternoon and at night.

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

.MARINE...
-- Changed Discussion --Marine dense fog advisory remains in effect for the western
Sound til 10 AM. Vsbys have improved elsewhere but some patchy
fog may still be around especially this morning. SCA also
remains in effect for all waters as S flow increases today, with
gusts 25-30 kt and ocean seas building to 5-7 ft.

A few tstms this evening could produce gusty winds across New
York Harbor, Western Long Island Sound, and the ocean waters
west of Fire Island Inlet.

Potential for any S gales tonight ahead of the approaching
front appears low as a inversion limits potential for a LLJ
aloft to mix to the surface, but there could be a post-frontal
surge of NW-N wind late tonight, with some gusts briefly hitting
35 kt especially on the harbor and ocean. SCA extended into all
of Mon night for all the waters as a result, and into daytime
Tue for the ocean waters. Some near shore gusts to 25 kt may
still be possible on NY Harbor daytime Tue as well. Elevated
ocean seas should linger E of Fire Island Inlet Tue night into
Wed as winds diminish.

For long term, regarding wind gusts, probable SCA conditions
for Thursday and Thursday night, mainly on the ocean. Regarding
seas and wave heights, SCA conditions are probable much of the
timeframe for the ocean. Non-ocean zones are below seas/wave SCA
thresholds the whole marine long term period with some possible
SCA wind gusts Thursday into Thursday night. All waters are
forecast to be below SCA Friday night.-- End Changed Discussion --

.HYDROLOGY...
Showers and embedded thunderstorms are expected late today into
tonight, with QPF mostly around an inch, but closer to 1.25 inch
across NE where tstm potential will be greater. Main concern
remains localized minor nuisance/urban/poor drainage flooding.

.TIDES/COASTAL FLOODING...
Water levels have been lower than fcst, and with astronomical
tide levels trending slightly lower for tonight, this will
limit any minor coastal flooding to isolated spots along some
shoreline locations of the South Shore Bays of Long Island and
the western Long Island Sound shoreline along Southern Fairfield
CT.

Timing of wind shift compared to time of high tide does not give
much factor to offshore flow. Time before high tides will be
mostly onshore. Both South Shore Bays and Western Long Island
Sound will have high tide pass before more continuous gusty NW
offshore flow gets established.

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until noon EDT Tuesday for ANZ331-332-335-
338-340-345.
Dense Fog Advisory until noon EDT today for ANZ335.
Small Craft Advisory until 6 PM EDT Tuesday for ANZ350-353-355.-- End Changed Discussion --

SYNOPSIS...BG/JM
NEAR TERM...BG/MET
SHORT TERM...BG
LONG TERM...JM
AVIATION...JM
MARINE...BG/JM/MET
HYDROLOGY...BG/JM
TIDES/COASTAL FLOODING...