570
FXUS61 KOKX 310314
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1114 PM EDT Tue Jul 30 2024
.SYNOPSIS...
A weak cold front or surface trough approaching from the west
will move through Wednesday evening. A series of weak fronts
will follow from Thursday into Monday.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --
Lowered chances for precipitation for the next couple of hours
as any showers remain west of the forecast area (a lone shower
over Pike County in PA). Otherwise, forecast is on track.
Shortwave ridging between an upper low over eastern Canada and
an upper trough over the Ohio Valley will largely keep the area
quiet this evening. Main activity over east central PA will be
the primary focus, which lifts NE through overnight. CAM`s
generally weaken this convection due to the loss of daytime
instability before it can get into the area, but so show some
activity developing out ahead over the area or advecting in from
the SW. By that time, there is very little CAPE, so expecting
mainly showers with a few thunderstorms. The associated upper
trough does provide some lift, enough to think that whatever
convection makes it here may work east across coastal areas into
Wednesday morning. There is no severe weather threat at this
time due to lack of instability and a weakly sheared
environment. However, with PW increasing to around 2 inches,
brief downpours are possible.
Gusty south winds 25-30 mph will continue in/around the NY
harbor and far western Long Island Sound early this evening,
then gradually diminish.
For Wednesday, any showers and thunderstorms over eastern
sections in the morning lift NE. However, with the upper trough
slowly working across the area and a destabilizing airmass,
expect redevelopment. Initially, expect the development north
and west of NYC, but working east through the day. There could
be multiple bands translating W to E with the individual cells
tracking SW to NE. While it will not be raining much of the
time, there is a good chance for most locations to see a shower
and/or thunderstorm. Thus, rain chances are in the 50-60 percent
range. Once again severe is unlikely, but can`t rule out a
severe thunderstorm across the interior where the higher CAPE
will exits.
Increasing cloud cover tonight with the approaching upper trough
will limit cooling overnight, but will keep temperatures cooler
on Wednesday. Lows will generally be in the 70s with high in
the 80s, warmest away from the immediate coast. Right now, heat
indices around 95 are forecast to be spotty across metro NE NJ.
Should we realize more sun than forecast, values could be more
widespread.-- End Changed Discussion --
&&
.SHORT TERM /WEDNESDAY NIGHT/...
The cold front or surface trough push through Wednesday evening,
ending the convective threat. Winds will shift around to the
west with some lowering of dew points, but still humid.
Skies will clear as well. Lows will be in the upper 60s well
north and west, to the lower/mid 70s elsewhere.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Key Points:
* Multiple rounds of showers and thunderstorms possible each day
into Monday.
* Heat index values over 95 likely Thu/Fri and possibly into the
weekend, especially for NE NJ, the NYC metro area, the lower
Hudson Valley, and the interior CT river valley.
An active upper flow will be in place through much of the period,
with the area on the southern fringe of the westerlies and several
upper level disturbances moving through, which should bring diurnal
convection each day through Monday. The best days for convection
look to be Thu and again Sat/Sunday. Coverage may be more limited on
Fri as any lead disturbances ahead of a closed low over the Ohio
Valley will be moving through downstream shortwave ridging.
The closed low is poised to affect the area through the weekend.
Heat should begin building on Thu with deep mixing and downslope
flow, with more in the way of sunshine before any afternoon
convection. High temps will be in the lower/mid 90s away from south
facing shorelines, with heat index values in the 90s, possibly
touching 100 in urban NE NJ, parts of NYC, and scattered locations
across CT/Long Island just in from the shoreline where higher
dewpoints may advect in from off the ocean/Sound on afternoon sea
breezes.
Shortwave ridging on Friday should allow for heat and humidity to
continue to build, before potential for late day/evening convection
ahead of the aforementioned lead shortwave.
Friday should feature high temps similar to those on Thu but
slightly higher dewpoints, with 95+ heat index values expected for
most of the area, and reaching/surpassing 100 mainly across NE NJ
and parts of NYC.
Temps for the weekend may not be quite as warm but could be offset
by higher dewpoints to yield 95+ heat index values in spots,
especially NE NJ and in/around NYC.
Heat advisories will likely be needed for parts of the area for Thu-
Fri, and possibly into the weekend. There will be little relief at
night as temperatures bottom out in the upper 60s and 70s.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
An upper level low will move north into southern Canada tonight.
A weak cold front approaches tonight through Wednesday.
VFR this evening, with MVFR to IFR conditions moving after 06Z
tonight. The metro terminals should generally be MVFR, but
brief IFR conditions are possible, especially when showers move
through around daybreak Wednesday. Outlying terminals have a
better chance of IFR and potentially brief periods of LIFR, with
highest chances for IFR for KGON. VFR conditions return
Wednesday afternoon.
Southerly winds diminish tonight, with gusts ending at or just
after 02Z in the metro terminals. However, occasional gusts to
25 kt are possible through 04-05Z. S to SW around 10 kt or less
Wednesday.
SHRA expected to move through tonight, after 06Z. Then, another
round of SHRA and possibly a TSRA Wednesday afternoon, after
18Z.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
AMD expected for change in flight categories tonight.
OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...
Wednesday night and Thursday: VFR.
Friday-Sunday: Chance of MVFR or lower in afternoon/evening
showers/tstms.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Enhanced low-level jet just east of NJ and into the NY Bight
continues to produce wind gusts 25-30 kt on the ocean W of Fire
Island Inlet, NY Harbor, and the western Sound. SCa expanded to
include those areas until 03Z. Thereafter, SCA for the ocean
waters remains in effect into Wednesday with seas building to 5
to 6 ft.
Marginal SCA conditions for seas around 5 ft could linger into
Wednesday evening before subsiding. However, confidence to
extend the SCA into that time was low.
Increasing/persistent S-SW flow may allow ocean seas to
build to 5-6 ft late Sat night into Sunday.
&&
.HYDROLOGY...
Multiple rounds of showers and thunderstorms are possible
tonight into Wednesday, again on Thu, and also this weekend.
While widespread flood impacts are not expected, localized urban
and poor drainage flood impacts are possible.
&&
.TIDES/COASTAL FLOODING...
A high rip current risk should continue into Wed with S flow 15
kt and incoming 5 ft/7-sec period swells. Winds diminish and
turn more SW-W on daytime Thu, but still expect at least a
moderate risk, possibly high into Thu morning, due to residual
3-ft swell.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...High Risk for Rip Currents through Wednesday evening for NYZ075-080-
081-178-179.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT Wednesday for ANZ350-353-
355.-- End Changed Discussion --
&&
$$
SYNOPSIS...BG/DW
NEAR TERM...BG/JP/DW
SHORT TERM...DW
LONG TERM...BG/NV
AVIATION...JP
MARINE...BG/DW
HYDROLOGY...BG/DW
TIDES/COASTAL FLOODING...