219
FXUS61 KOKX 171437
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1037 AM EDT Thu Apr 17 2025
.SYNOPSIS...
A series of weak surface troughs move through the area today.
High pressure then builds overhead Thursday night and then
offshore on Friday. A warm front lifts north of the area late
Friday into Friday night. A cold front moves through Saturday
night into Sunday morning followed by brief high pressure. Then,
a frontal system impacts the region late Monday through late
Tuesday. High pressure then follows into Wednesday.
&&
.NEAR TERM /THROUGH TONIGHT/...
No changes with this update as forecast remains on track with a
dry cP air mass in place. Previous discussion follows.
Key Messages:
* Frosty conditions expected across eastern LI and coastal
central & eastern CT late tonight into Fri AM, where growing
season has begun. Frost advisory in effect.
NE upper troughing around SE Canadian closed low slides offshore
this afternoon, with heights gradually rising later this
afternoon into tonight with weak ridging. At the surface,
surface troughing dissipates and slides east this evening, with
weak high pressure sliding through overnight.
Deep WNW-NW flow continues with breezy conditions of 15-20G20-
30 mph into the afternoon, diminishing quickly in the evening
as high pressure slides in. A moderating airmass and mostly
sunny skies (early morning stratus west of Hudson should quickly
erode) in this deep mixing-offshore flow regime should have
temps rising several degrees warmer than yesterday, with highs
in the upper 50s (interior) to lower 60s (city/coast).
Good radiational cooling conds tonight as high pressure slides in,
with lows in the lower to mid 30s across interior and LI pine
barrens. Mid 30s to lower 40s elsewhere, except mid 40s NYC/Nj
metro. Frost advisory issued for the frost conditions expected
across eastern LI and coastal central and eastern CT late
tonight into Fri AM, where Spring growing season has started.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Key Messages:
* Temps moderating to several degrees above seasonable for areas
west of the Hudson River on Saturday, with highs in the upper 60s
to lower 70s.
* Unseasonably warm temperatures (10 to 20 degrees above normal)
areawide Saturday, particularly away from the coast, with
highs in the 70s to lower 80s.
* Cold water submersion dangers for recreational boaters,
canoers or kayakers as air temperatures warm this weekend,
but water temps remain in the 40s.
East coast ridging holds strong through the period, with
amplifying deep SW flow (subtropical connection) between SE US
ridging and an amplifying northern stream shortwave/closed low
tracking east through Ontario into Quebec. At the surface, high
pressure slides offshore Friday with a strengthening low
pressure system tracking from the Great Lakes into southern
Quebec Fri Night into Saturday. An associated warm front lifts
NW of the region late Friday into Friday Night in response to a
developing 45-50kt SW llj. This will result in breezy
conditions Friday into Saturday, but also also advect in a much
warmer airmass Friday Night into Saturday.
Dry conditions expected for both Friday and Saturday, with just a
slight chance of a shower late Fri/Fri Night across interior with
warm frontal passage to the north. Otherwise, high clouds
rounding SE US ridging will filter sunshine through the period.
Strong waa and breezy southerly flow Fri afternoon (15-20g25-35mph)
will have areas west of the Hudson River climbing well into the 60s
to around 70 on Friday. East of the Hudson River, the strengthening
southerly flow will likely have highs progressively capped in the
50s towards south coastal areas, with flow off of mid 40s degree
waters. Potential for a strong coastal jet with sustained S
winds of 25-30G35 mph in the late aft/early eve for
Brooklyn/Queens/W LI.
Flow veers more to the SW Fri night into Sat as area is squeezed
between Canadian low pressure and associated cold front to the north
and SE Atlantic high pressure to the south. Mild temps in the
upper 40s to mid 50s Fri Night. With continued WAA in gusty SW
flow (15-20g25-35mph), mixing to 900mb, and more continental
wind flow, widespread temps in the 70s to lower 80s likely on
Saturday away from southern and eastern coastal areas.
Deep closed low slides into Quebec Sat Night, with associated cold
front sinking south through the region late Sat night into early Sun
AM. Ahead of it, pre-frontal trough approaches the region Sat
aft. Convectively induced vorts streaming through the upper flow
could trigger iso-sct shower activity (particularly NW of NYC)
in a moistening profile (+2 std PWAT). Overall limited forcing
and low- level convergence, and lacking instability due to
strong mid- level capping, should preclude deep convection.
Temps Saturday Night will remain unseasonably mild (50s to
around 60 - within a few degrees of normal highs for this time
of year), with only gradual CAA.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Weak high pressure and upper level ridging move over the region
Sunday and Sunday night. Expect mainly dry conditions during this
time period, however temperatures will be cooler than Saturday.
Expect highs in the 60s and lower 70s.
The weak high and upper level ridging slide east on Monday, allowing
a frontal system to approach late in the day Monday and Monday
night. This should bring at least a chance of showers to the region
Monday evening through Tuesday morning. The system slides east of
the area Tuesday, with high pressure building back into the region
for late Tuesday into Tuesday night. The high will remain over the
area through most of Thursday. Another weak frontal system may
impact to end the week.
Monday will be the coolest day of the week with highs in the middle
and upper 50s to near 60. Temperatures will gradually warm through
mid week topping off with highs in the 60s and lower 70s Wednesday
and Thursday.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
High pressure builds in from the west today and settles south of the
area tonight.
VFR through the TAF period.
WNW winds around 15kt with gusts 20-25kt, back more to the west
during the afternoon. This evening, winds and gusts diminish,
with the outlying terminals possibly losing the gusts around
23Z. And in the metro area gusts end by 02Z Friday. Winds
tonight eventually become light and variable.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments possible for timing of wind gusts.
.OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
Friday: VFR. S winds G20-30kt. LLWS aft 00Z with 50kt at 2kft.
Saturday: Mainly VFR. Chance of showers, mainly NW interior. SW
winds G20-25kt.
Sunday: VFR. NW wind gusts 15-20kt possible.
Monday: VFR early, then sub VFR late day and at night with a chance
of showers.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
SCA gusts have subsided across the ocean waters with wind wave
dominant ocean seas following suit. There may still be an
occasional / marginal SCA gusts possible across nearshore waters
into the afternoon, but not frequent enough to extend SCA. Sub
SCA conditions expected tonight into Friday AM as high pressure
moves across the waters.
SCA conditions expected to develop on the ocean Fri aft/eve in
strengthening S/SW flow with gusts mainly 25 to 30 kt and
building seas, continuing through Saturday. Nearshore SCA
conditions likely around NYC/W LI Fri aft/eve with coastal jet
development across the entrance to NY Harbor. Nearshore SCA
gusts possible Sat aft into early eve as well.
Cold frontal passage expected late Sat Night into Sun Am, with
NW windshift. Winds appear marginal for SCA, but SCA southerly
swells likely linger into Sunday.
Ocean Seas fall below 5ft Sunday night. Sub- SCA conditions are
then expected Sunday night through much of next week with a
weak pressure gradient over the area.
&&
.FIRE WEATHER...
Frequent northwesterly wind gusts of 20 to 25 mph are expected to
develop by mid to late this morning, with min RH values falling
into the lower to mid 20 percent range this afternoon.
An SPS continues today for the Lower Hudson Valley, New York
City Metro, and Long Island due to an elevated threat of
wildfire spread. This is collaborated with neighboring WFOs and
NY State land manager due to drying fuels.
Light southerly winds early to mid Friday morning will increase
to the 25 to 30 mph range late Friday morning into Friday
afternoon, with min RH values in the 35 to 40 percent range.
&&
.HYDROLOGY...
There are no hydrologic concerns through the middle of next week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Frost Advisory from 2 AM to 8 AM EDT Friday for CTZ010>012.
NY...Frost Advisory from 2 AM to 8 AM EDT Friday for NYZ079-081.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BC/NV
NEAR TERM...JE/NV
SHORT TERM...NV
LONG TERM...BC
AVIATION...BC/JMC
MARINE...BC/NV
FIRE WEATHER...
HYDROLOGY...BC/NV