AFDOKX

Area Forecast Discussion
National Weather Service New York NY
135 PM EDT Sun Aug 17 2025

.SYNOPSIS...
Offshore high pressure will move east today. A pre-frontal 
trough will move through this afternoon and evening, followed by
a cold front later tonight. Strong high pressure will then 
build southeast from Ontario and Quebec into New England on 
Monday, then move off the New England coast on Tuesday.
Hurricane Erin will pass well offshore on Wednesday, with a
weakening frontal system approaching from the west. The frontal
system and Erin will pass well out into the Atlantic on
Thursday. High pressure will return by late week. Please refer
to National Hurricane Center forecasts for further information
on Erin.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today a SW flow will advect warmer and more humid air into the 
region, with one day of heat index values in the mid/upper 90s 
from the NYC metro area north/west as temperatures there reach 
the lower 90s, with afternoon dewpoints in the upper 60s and 
lower 70s. Farther east across most of Long Island and SE CT, 
high temps will reach the mid/upper 80s with dewpoints in the 
lower 70s, with max heat index values in the lower 90s. 

A bkn line of late day/evening tstms is possible in association
with a pre-frontal trough over the area and a shortwave trough 
approaching from the eastern Great Lakes region. Activity 
should be mainly from the NYC metro area north/west late this 
afternoon, then spreading SE into the rest of the area after 
dark. Best forcing with this wave will be mostly south/west but 
should clip the NYC metro area. CAPE will be limited due to weak
mid level lapse rates (MLCAPE up to 1000 J/kg), but with 
relatively dry sub- cloud and mid level air, also northwesterly 
0-3 km shear normal to line motion, stronger cells may be 
capable of producing gusty winds. 

A cold front dropping from the north late this evening into the
overnight will bring a wind shift out of the N-NE which should 
become gusty especially in the NYC metro area and along the 
coast where gusts could peak as high as 25-30 mph. Lows tonight 
will range from the mid/upper 60s for NYC metro and the coast, 
to the upper 50s/lower 60s inland.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
High pressure and cooler air will continue to build in on Mon.
With the cooler air mass, also bkn clouds, plus isolated-sct 
showers especially on Mon, high temps Mon/Tue should only make 
it to the mid/upper 70s. Mon night looks mostly dry, with low 
temps ranging from the mid 50s inland to the mid 60s in/around 
NYC. Gusty NE winds on Mon should abate somewhat from Mon night 
into Tue night while becoming easterly. 

The frontal boundary to the south will start to return north Tue
night as the high retreats to the east and as the outermost
circulation of Hurricane Erin approaches. This will bring
chances for showers and possibly a tstm mainly late at night. 
With no appreciable change in air mass, low temps Tue night
should be similar to those of Mon night.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Only impacts from Hurricane Erin will be with the ocean and 
ocean shorelines impacted by waves/swell. See marine and 
tides/coastal flooding sections for more details. Otherwise, for
the land areas, no significant rainfall, and winds stay well 
below advisory thresholds during the long term. Please refer to 
the National Hurricane Center on the latest forecasts on Erin.

Mid levels convey trough moving into region with NW flow
Wednesday into Wednesday night. The trough shifts northeast of
the region Thursday through Friday. Slow ridging trend evident 
heading into next weekend. The mid level circulation associated 
with Erin moves well northeast of the region out in the 
Atlantic.

At the surface, a weak frontal boundary will work its way back
north into the local region Wednesday and eventually 
dissipate. Meanwhile, Hurricane Erin is forecast pass well 
offshore in the Atlantic between Wednesday night and early 
Friday. As it does so, the increase in pressure gradient between
itself and high pressure to the north and west, will make for 
more gusty NE to N flow.

Rain showers in the Wednesday through Thursday timeframe are
still indicated from mean precipitation plots in LREF. This is
probably with the lingering weakening front with perhaps some 
interaction of tropical moisture. Operational GFS, ECMWF and 
Canadian models actually are not indicating much of any shower 
activity. Only chance POPs for these showers and less than 50 
percent. 

Mainly dry conditions Thursday night through Saturday night in
the forecast with return of high pressure from the north and 
west.

Regarding temperatures, below normal values forecast Wednesday 
through Thursday night and then a return to near normal values 
for Friday through Saturday night.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A cold front moves through the terminals late this afternoon
through tonight.

VFR most of today. MVFR or perhaps briefly lower conditions are
possible in showers and thunderstorms, mainly late afternoon 
into tonight, around 21Z to 03Z. Confidence is a bit higher for
NYC terminals, KHPN and KSWF than the eastern terminals. 
Showers remain in the vicinity late tonight into early Monday 
with MVFR cigs expected. VFR returns mid to late Monday morning.

S/SW winds around 10-13 kt with gusts up to 20 kt this 
afternoon. These relatively higher winds and wind gusts last 
into early this evening before decreasing briefly and 
eventually shifting to more of a northerly direction late. Winds
pick back up late tonight into early Monday to near 10-15 kt 
and gusts 20-25 kt. Winds gradually diminish through Monday.

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

Timing of thunderstorms could be off by 1-2 hours from TAF.

Gusts may be more occasional today.

.OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...

Monday Afternoon: MVFR with diminishing gusts.

Tuesday: VFR.

Wednesday: MVFR or lower possible with a slight chance of 
showers.

Thursday: MVFR. NE wind gusts around 20-25 kt.

Friday: VFR.

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

&&

.MARINE...
SCA issued for all waters. After a cold frontal passage, NE 
winds should gust up to at least 25-30 kt from tonight into 
early Tue morning. A few gusts up to 35 kt may be possible on 
the ocean late tonight, but of too short duration to warrant a 
gale warning. Winds diminish Mon afternoon, but a persistent 
NE-E flow should maintain hazardous ocean seas into Mon night. 
Swells from Hurricane Erin should then start to arrive, with 
ocean seas remaining at 5-6 ft into Tue. 

An extended period of SCA cond expected for the ocean and the
sound E of Orient Point, with swells from Erin and eventually 
gusts 25-30 kt on the ocean on Thu as Erin passes well to the 
SE. Peak ocean seas are forecast from late Wed night into Thu,
in excess of 10 ft and reaching 12-16 ft out east.

&&

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

&&

.TIDES/COASTAL FLOODING...
The risk for rip currents should increase to moderate today,
with a stronger S-SW wind up to 10-15 kt with a longer period 
2-ft SE swell at 10 sec. 

A moderate rip current risk is forecast for Monday though it was
borderline high risk due to increasing swell and waves toward
the afternoon.

There is potential for dangerous surf and rip currents from Tue
onward, as building long period swells from Erin arrive. 
Minor coastal flooding and beach erosion may also become
possible during this time. Bias-corrected STOFS guidance
indicates only localized minor flooding, but departures 1/2 ft 
higher than fcst (reasonable worst case) could lead to more 
widespread minor flooding with the Thu night high tide cycle.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 2 AM to 9 AM EDT Monday for ANZ331-
     335-338-345.
     Small Craft Advisory from 2 AM to noon EDT Monday for ANZ332-
     340.
     Small Craft Advisory from 2 AM Monday to 6 AM EDT Tuesday for 
     ANZ350-353-355.

&&

$$

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