467
FXUS61 KOKX 031935
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
335 PM EDT Wed Jul 3 2024

.SYNOPSIS...
High pressure will remains situated offshore tonight. A trough of
low pressure moves into the region on Thursday and stalls over the
area Thursday night into Friday morning. A warm front then
lifts through Friday afternoon into night, with a trailing cold
front approaching Saturday. The front stalls and weakens near
the region late this weekend, before potentially lifting back
north Monday night into Tuesday.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
High pressure offshore will maintain a light S-SW flow over the
region, promoting muggier conditions than what we`ve had for the
past couple of nights. Can`t rule out a shower late at night north
and west of NYC with a weak shortwave approaching from the west.
Lows around 70 in NYC metro with mid to upper 60s elsewhere.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
A weakening cold front and pre-frontal trough approach on Thursday.
The cold front dissipates before reaching the forecast area, however
the trough should move in during the afternoon, then settle over us
at night. SBCAPEs, primarily west of the Hudson River, may build to
500-1500 J/kg in the afternoon. With the surface trough, convergence
with sea breezes, and support from a shortwave aloft, scattered
showers and thunderstorms will be possible in the afternoon and
evening hours, followed by more isolated shower activity overnight
with diminished instability. Not anticipating severe thunderstorms
at this point with based on mid level lapse rates and fairly weak
bulk shear, but strong gusts may still be possible mainly along the
western fringe of the forecast area with the best combination of
CAPE and shear.

PWATS increase to 2.0-2.25 inches by the end of the day, but the
area and magnitude HREF probs of 3"/3hr rainfall of 10 to 30 percent
have shrunk and remain confined to SE PA. So while localized
minor/poor drainage will be possible with the fairly slow forward
motion of any storms, the flash flooding threat still looks minimal.

Highs generally in the 80s Thursday with perhaps a couple of spots
in NE NJ reaching 90. Warm and muggy conditions for Thursday night
with some late night stratus/fog development. Lows mostly in the
upper 60s to lower 70s.

It appears that the surface trough shifts slightly Friday morning
over or near the forecast area before lifting north as a warm front
later in the day in response to strengthening low pressure shifting
NE through the Great Lakes. Given the uncertainty regarding where
the boundary begins its shift to the north, really can`t rule out a
shower at any part of the day. Perhaps better chances over the
eastern zones in the morning with a shortwave still in the vicinity,
then away from the coast during the afternoon as modest CAPE builds.
Highs again mostly in the 80s with some NJ spots reaching 90.

One other thing that will need to be monitored is the potential of
heat advisory criteria being met mainly in parts of NE NJ. Did not
have enough coverage to go with an advisory for Thursday-Friday,
however there is a better chance of an advisory being needed for the
Friday-Saturday period. See the long term section regarding
Saturday.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A hot and humid summer pattern persists in the long term, featuring a
longwave trough over the Central US and a Western Atlantic ridge,
with well defined disturbances moving through the flow aloft Fri
night and again on Tuesday.

First disturbance lifts a warm front through to start the period
Friday night into Saturday, bringing the potential of showers and
thunderstorms as it does so. Global guidance progs PWATs increasing
to over two inches by Saturday per global guidance, and will bring
the risk for torrential downpours with any potential convection. WPC
has much of the region outlined in a marginal risk for excessive
rainfall on Saturday. CSU`s MLP has similar output, though with a
bit higher risk north and west of NYC into the lower Hudson Valley.
All this said, any flood threat outside training convection is
likely localized in coverage. Also given the warm, moist environment
and modest unidirectional shear, there is potential for some strong
to severe thunderstorms to develop, with isolated damaging wind
gusts the primary hazard.

In addition to the rain potential, an abundantly moist air mass and
temperatures in the 80s will offer a hot and humid feel to the
afternoon. It`s possible heat indices could approach 100F in parts
of NE NJ, and this will need to be monitored should a heat headline
be needed, especially given the potential on Friday for these values
to reach the mid 90s in this same area. Deep layer moisture shunts
to the south and east by Sunday as the front washes out over the
region, bringing lower humidity and drier conditions for into early
next week. Surface dew pts fall from the mid 70s on Saturday back
down into the 60s Sunday. This should allow Sunday to be the more
comfortable day of the weekend, though still hot, with afternoon
temperatures in the mid to upper 80s, and perhaps the lower 90s
around metro NYC and NE NJ.

Conditions remain hot but dry on Monday, before the next disturbance
looks to arrive late Monday into Tuesday, once again bringing
increased chances for showers and thunderstorms. Largely stayed
close to national blended guidance for this update.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
VFR as high pressure along the coast gradually works farther
offshore through this evening with a weak frontal system approaching
late tonight. Some BKN cigs possible late tonight but still VFR.
Will introduce Prob30 for TSRA starting 20z Thu but there is high
uncertainty of coverage at this time frame. Best chance appears to
be N and W of city terminals initially before decaying across the
terminals during the evening hours.

Regarding wind, coastal sea breezes 10-15kt weaken later this
evening but not before occasional gusts 20kt through early evening.
Mainly S-SW winds 10-15 kt Thursday with coastal sea breezes
redeveloping.

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

No unscheduled AMD expected through most of the TAF period but
amendments are possible later Thu afternoon in or around TSRA.

OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...

18Z Thursday: MVFR or lower cond possible with any afternoon or
nighttime showers/tstms. IFR cigs possible late at night at the
Long Island/CT terminals.

Friday and Saturday: MVFR or lower cond possible at times with
continued chance of showers/tstms.

Sunday and Monday: VFR.

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

&&

.MARINE...
Prevailing sub-SCA conditions through Friday. However, marginal SCA
gusts possible into this eve as well as Thu aft/eve at the entrance
to NY Harbor and western Great South Bay with coastal jet
development. Ocean seas may approach 5 ft in this area Thursday.

SCA conditions may develop on the ocean Sat afternoon/night as long
fetch S flow increases to 15-20 kt, with a few gusts close to 25 kt.
This should builds seas to 5 ft during this time before conditions
subside Sunday AM. Sub SCA conditions then expected on all waters
thereafter into early next week.

&&

.HYDROLOGY...
Isolated slow moving thunderstorms with heavy downpours producing
2"/hr rainfall rates are possible Thurs aft/eve, mainly west of the
Hudson River. The threat is low and isolated at this point. Should
any flooding occur, it would most likely be minor/poor drainage. For
Friday, the flooding type once again will most likely be minor,
and this time including the entire forecast area.

A disturbance and slow moving frontal boundary approach Friday
night into Saturday and will bring the potential for torrential
downpours with any associated convection. Any flood threat
outside training convection is likely localized in coverage,
with minor nuisance flooding the most likely solution at this
point.


&&

.TIDES/COASTAL FLOODING...
There is a moderate risk for rip current development along local
Atlantic facing beaches today and Thursday with a combo of
building southerly wind wave and 1 to 2 ft E/SE swell.

Rip risk could become locally high for W LI and NYC beaches in
the late aft/eve both days with enhanced seabreeze formation
and large tidal range.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$

SYNOPSIS...JC/DR
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...DR
AVIATION...IRD
MARINE...JC/DR
HYDROLOGY...JC/DR
TIDES/COASTAL FLOODING...