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Forecast Discussion for New York City/Upton, NY
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923
FXUS61 KOKX 170835
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
435 AM EDT Fri Jul 17 2026
.WHAT HAS CHANGED...
Much of the area now in a slight risk for severe thunderstorms
on Saturday.
NYC metro, NE NJ, LI and S CT now in a slight risk for excessive
rainfall on Saturday.
&&
.KEY MESSAGES...
1) Reduced air quality and visibility from wildfire smoke
gradually improve today before likely returning tonight into a
portion of Saturday. An air quality alert remains in effect
until midnight for NE NJ.
2) Showers and thunderstorms Saturday into Saturday evening have
the potential to bring heavy rainfall, isolated to scattered
severe thunderstorms, and isolated to scattered flash flooding.
3) Another round of showers and thunderstorms possible late
Tuesday into a portion of Wednesday.
&&
.DISCUSSION...
.KEY MESSAGE 1...
An air quality alert remains in effect per NJDEP until midnight
for NE NJ. There are currently no active alerts from NYDEP and
CTDEEP.
Smoke from Canadian wildfires continues to affect the area early
this morning. Visibilities remain 3-5SM at most sites due to
the smoke with unhealthy to very unhealthy air quality. The
latest near surface smoke modeling from the HRRR and RRFS shows
the plume dropping south of the area this morning as high
pressure builds across the northeast. This should bring an
improvement to air quality and visibilities. Some patchy smoke
could linger near the coast in the afternoon as they will be
closest to the plume that should reside across central/southern
NJ into the Middle Atlantic. Smoke aloft may also be limited
compared to recent afternoons allowing temperatures to reach the
mid to upper 80s.
The high pressure will shift off the coast tonight allowing a
return flow to set up above the surface. The smoke likely
returns from south to north and potentially from the NW across
the area. Some drop in visibility and air quality is possible.
Modeled near surface smoke concentrations do not appear as high
as what has occurred in the last 24 hours, but certainty worth
monitoring for potential poor air quality at times into Saturday.
A fast moving frontal system passes across the region late
Saturday into Saturday night, which should push the smoke
offshore.
.KEY MESSAGE 2...
A shortwave trough digs down into the Great Lakes Saturday
and swings across eastern Canada and the northeast Saturday
night. The associated cold front will move across the area late
Saturday into Saturday night.
Increasing SW flow ahead of the incoming trough and front will
set the stage for a deep, moist airmass over the area. PWATs
are progged to reach around 2 inches, and could potentially get
a bit higher (~2.25 inches). The larger scale guidance is
signaling shortwave energy ahead of the main system to pass
across the area Saturday afternoon. The 00z CAMs are signaling
the potential for convection associated with this energy.
Another round of convection is expected late in the day and
evening as the main upper trough and cold front near the area.
There may also be support from a 100-120 kt jet stream across
northern New England and SE Canada, with the local area falling
within the right entrance region, a source for larger scale
lift.
The main threats with the showers and thunderstorms Saturday
into Saturday evening are heavy rainfall, isolated to scattered
severe thunderstorms and isolated to scattered flash flooding.
SPC has upgraded much of the area to a slight risk for severe
thunderstorms Saturday. The amount of destabilization is a
concern due to potential of multiple rounds of convection,
lingering smoke, and clouds. Latest guidance is keeping the
highest surface based instability mainly to our south. There is
a chance for higher surface based instability to nudge north
into the area in the afternoon ahead of the main cold front
passage. Bulk shear values are forecast to range from 30-40 kt,
strongest late in the day and evening. While there are concerns
with the amount of destabilization, shear and potential large
scale forcing could still lead to the potential of damaging
wind gusts in any of the stronger storms that develop. There is
also a risk for isolated tornadoes with directional shear from
the surface to 5kft. The severe threat may linger beyond sunset
until the cold front moves across the area.
The NYC metro, NE NJ, Long Island, and S CT are now included in
a slight risk Saturday for excessive rainfall based on
collaboration with neighboring offices and WPC. The potential
exists for heavy rainfall with deep moisture, high freezing
levels and large warm cloud depths (13-15kft). The fast flow
aloft should preclude significant flash flooding concerns.
However, rainfall rates could peak around 1.5-2" per hour in
the heaviest showers/storms. These rainfall rates are
problematic over the urban corridor of NE NJ, NYC metro, I-95
corridor in CT, and parts of Long Island. The flash flooding
risk should isolated to scattered. Decided to hold off on a
flood watch, but one may be issued as confidence where the
heaviest rainfall may occur increases over the next 12-24 hours.
Basin averaged rainfall is around 1 inch across the area with
locally higher amounts possible.
.KEY MESSAGE 3...
Dry conditions return on Sunday and continue into Monday with
seasonably warm conditions expected through much of the week. A
much more humid airmass returns Tuesday into Wednesday.
Comfortable humidity levels and near seasonable warmth may
return to end the week.
There is good agreement among the deterministic models and ensemble
means for an amplified shortwave trough to swing across the
northeast late Tuesday through mid week. This pattern likely brings
a frontal system across the area late Tuesday into Wednesday.
Guidance has sped up the timing of the system with the latest
model consensus indicating the highest probabilities for
showers/thunderstorms Tuesday evening into early Wednesday. It
is much too early for any confidence in potential severe weather
impacts or hydro impacts. Conditions should dry out to end the
week based on the latest model consensus despite the upper
trough lingering over the region.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
A cold front continues to move south of the area as high pressure
builds in from the W today.
MVFR/IFR vsbys from wildfire smoke to start the morning. It
should be noted that cigs under 5 kft being reported in several
METARs are likely erroneous and a result of the smoke impacting
the ceilometer. Vsbys likely improve to VFR after 12Z as the
plume shifts south. Smoke then likely returns in the evening,
mainly after 00Z, potentially bringing MVFR vsby restrictions
once again into Saturday.
A general NW flow persists thru at least mid morning before
backing SW through the day. Winds then settle in a light S
direction or become light and variable toward 00Z.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of vsby improvement and return to VFR this morning could be
off by a couple of hours.
Occasional gusts 15-18 kt possible this afternoon.
.OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY...
Late tonight: MVFR likely, IFR possible, with smoke.
Saturday: MVFR or lower possible in showers/tstms and smoke.
Sunday and Monday: Mainly VFR unless there are smoke impacts.
Tuesday: A frontal sys may bring MVFR or lower cond and a chance of
tstms.
&&
.MARINE...
Conditions will remain below SCA levels through Saturday
morning. Increase S flow develops Saturday afternoon with the
likelihood of 25-30 kt gusts into the evening. Seas will also
build to around 5 ft. The hazardous seas could linger E of
Moriches Inlet into Sunday morning before subsiding later in the
day.
Weak flow over the waters Sunday night into Monday will lead to
conditions below SCA levels. The next chance for SCA conditions
will be late Tuesday into Wednesday with the next frontal
system.
Rip Currents:
The overall rip current risk is low today with light S/SW winds
at or under 10 kt and S swells 1-2 ft at 5 sec periods.
The risk increases to high at all local ocean beaches on
Saturday. Southerly winds strengthen to 15-20 mph as S swells
increase to 3-4 ft during the afternoon.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...Air Quality Alert until midnight EDT tonight for NJZ002-004-
006-103>108.
MARINE...None.
&&
$$
DISCUSSION...DS
AVIATION...DR
MARINE...DR/DS
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