000
FXUS61 KOKX 241626
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1226 PM EDT Mon Jul 24 2023
.SYNOPSIS...
High pressure will remain offshore through the upcoming week. A
couple of upper level disturbances will move through today and
Tuesday. A frontal system may approach the area by the weekend.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
An upper level trough will remain in place today as surface
high pressure remains off shore. Embedded in the trough is a
shortwave that is currently moving through northern NY and can
be seen on satellite water vapor imagery. A few more weaker
shortwaves will move through through the evening.
The trough will be the focus for some showers and thunderstorms
to affect the area from this afternoon into the early evening
hours, with the best chances across Northeast New Jersey and the
Lower Hudson Valley. These areas will see higher CAPE values
and stronger lift compared to the rest of the region. More
stable air across the coastal areas should mean a dry forecast
for these areas, but a stray shower or thunderstorm cannot be
ruled out here as well.
Though better dynamics look to be farther north and west of
this area, a strong storm is possible across the Lower Hudson
Valley and northeast New Jersey, with gusty winds being the main
threat.
PWATs will be on the rise with the introduction of a more humid
air mass. However, they are not expected to be too high,
approaching climatological average of around 1.50" for the date according
to the SPC climatology page. Therefore, an isolated thunderstorm
may bring 1" to 1.5" of rain.
Southerly flow will allow for a more humid air mass to work
into the area as dew points rise well into the 60s, while
temperatures will be similar to what they were Sunday.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
The upper trough remains over the northeast Tuesday as a weak
shortwave and surface trough develops inland areas will see
increased chances for showers and thunderstorms Tuesday
afternoon. While instability looks to be stronger with higher
CAPE values on Tuesday, the lift may not be as strong across
inland areas, so do not expect storms to be as strong. Slight
increases in PWAT values late Tuesday may continue the threat
for locally heavy rain with any of these storms.
The upper trough weakens and is replaced by zonal flow as the
shortwave pushes east Tuesday night into Wednesday. Dry
conditions are expected through this time period. Temperatures
warm to above normal for Wednesday.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
After the departure of an upper trough on Wed, the western Atlantic
ridge will expand westward and bring a classic Bermuda high heat
event for at least Thu-Fri and possibly into Sat depending on the
timing of a cold front sagging down from the north. High temps
likely to reach the 90s over a good portion of the area Thu-Fri, and
with min afternoon dewpoints in the lower 70s this should yield
widespread heat index values of 95+ over virtually the entire CWA,
and heat index values over 100 mainly just north/west of NYC on Thu,
and across a more widespread area on Fri. Diurnal late day tstms
possible each day mainly well north/west of NYC, with chance PoP in
those areas.
Incoming 00Z ECMWF guidance too late for inclusion in this forecast
suggests high temps may approach 100 in urban NE NJ on Fri, with max
heat index of 105, and that heat index values of 100 may be a little
more widespread on Thu, reaching into NYC and western Long Island.
It also shows a slower cold frontal passage this weekend, not
occurring until late Sat night/Sunday AM, allowing one more day of
widespread 90+ degree heat but also slightly drier air, with heat
index values 95-100 on Sat.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
High pressure will remain offshore to start the week.
This will mainly be a VFR forecast outside of any scattered
convection this afternoon. The best chance for convection will be
north and west of the NYC terminals. Have included a TEMPO for
TSRA to cover this threat. Confidence not as high at KEWR/KTEB
and will include a VCTS at those two terminals.
Mainly light S-SW winds become southerly during the daytime
hours, with some terminals increasing to 10-15 kt. Some gusts
either side of 20 kt may occur at KJFK/KLGA/KEWR late this
afternoon.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
G20kt may be possible at KLGA/KJFK, and G15-20kt at KEWR, late this
afternoon. An isolated shower or thunderstorm may also be possible
late this afternoon until just after sunset.
OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY...
Tuesday: Chance of a late day shower or thunderstorm, mainly NW of
the NYC metros, otherwise VFR.
Wednesday: VFR.
Thursday: Chance of a late day shower or thunderstorm at/near KSWF,
otherwise VFR.
Friday: Chance of a late day shower or thunderstorm, mainly NW of
the NYC metros, otherwise VFR.
Detailed information. including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
A Marine Weather Statement remains in effect for Long Island
Sound. The National Weather Service in coordination with the
United States Coast Guard have received reports of a large
debris field across Long Island Sound, caused by recent flooding
across New England.
With a weak pressure gradient in place through Wednesday, winds
and seas will remain below SCA levels through then.
On Thu/Fri, can`t rule out some ocnl gusts over 20 kt with the sea
breeze along the south shore of Long Island, impacting the south
shore bays of Long Island and the nearshore ocean waters. With S-SW
flow 15-20 kt especially on Fri, ocean seas are likely to exceed 5
ft on Fri.
&&
.HYDROLOGY...
No hydrologic concerns are expected through the end of the
week. Locally heavy rain in thunderstorms may lead to minor
flooding across inland areas such as Orange County, but
widespread flooding is not expected.
&&
.TIDES/COASTAL FLOODING...
The rip current risk for today is moderate as the surf height
increases to around 3 ft with the best chances of rip currents
during the mid to late afternoon.
Rip current risk drops back to low for Tuesday.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BG/JP
NEAR TERM...JP/JT
SHORT TERM...JP
LONG TERM...BG
AVIATION...BC/BG
MARINE...BG/JP
HYDROLOGY...BG/JP
TIDES/COASTAL FLOODING...