000
FXUS61 KOKX 121526
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1126 AM EDT Wed Jul 12 2023

.SYNOPSIS...
Weak high pressure moves out into the Atlantic today. A weak
cold front approaches the area from the north this afternoon
into tonight but will become stationary into early Thursday.
This front then moves farther north as a warm front Thursday
with an associated cold front approaching Friday and slowing
down as it moves in for Friday night. Unsettled conditions
continue this weekend into the first half of next week as a
series of frontal boundaries approach and move across the area.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Forecast still on track this morning.

Mid level height increases early today are shown by the
numerical weather prediction models but the height tendency
then becomes nearly constant.

Surface high pressure moves out into the Atlantic. Sunny skies
to start with increases in clouds in the afternoon.

Max temperatures from NBM, ranging from upper 80s to lower 90s.

There could be a few showers or gusty thunderstorms across
parts of the interior where there will be less of a cap. CAM`s
indicate this activity could begin as early as 20Z, with the
more likely time frame 22Z-01Z give/take an hour.

Dewpoints mix out during the day, decreasing to upper 50s/lower
60s for warmest spots but staying more in the upper 60s along
the coast where winds will become more southerly going into this
afternoon. Max forecast heat indices mainly in the lower 90s
with only a few spots hitting 95. This will be a limiting factor
for heat advisory as the areal extent of the 95 degree heat
indices will be quite small. This is why a heat advisory was not
issued.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
The models depiction of mid level height tendency remains nearly
constant tonight into Thursday and then more of a decrease
Thursday night into Friday. Vorticity increases more as well
Thursday night into Friday with a relatively stronger shortwave
moving in. Mid level heights slightly rise Friday into Friday
night as a weaker shortwave moves across.

At the surface, an approaching cold front comes to a halt
tonight and then moves back north as a warm front Thursday. An
associated cold front approaches from the west Friday and slows
down as it moves in for Friday night.

Another hot day expected Thursday but with temperatures forecast
to be a few degrees less than the previous day. Heat indices
with more humidity will be more in the mid to upper 90s for much
of the area as dewpoints trend a few degrees higher compared to
the previous day.

Heat advisory was not issued because of the lack of areal extent
of 95 degree heat index the previous day so for many locations
Thursday will be the only day with mid to upper 90s heat indices.

Shower and thunderstorm activity will be increasing Thursday,
becoming likely Thursday night through Friday night.

There will be increasing instability each day, with a large part
of the area potentially reaching at least 2000 J/kg of surface
CAPE Friday along with bulk shear 0-6 km AGL near 30-35 kt. This
will make for the possibility of some strong to severe
thunderstorms for both damaging winds and large hail.

Temperatures Friday are a few degrees cooler as a result so heat
indices are expected to remain below 95 for Friday.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Stuck fairly close to the current forecast/latest NBM guidance for
the long term period.

Expect a relatively active summer pattern in the long term as
ensemble means depict a closed upper low situated over Hudson Bay
slowly working south and east into Ontario though this weekend into
early next week as blocking over the North Atlantic begins to
weaken. This results in a general southwest flow aloft, with
multiple shortwaves passing through.

Unsettled conditions remain likely this weekend as another shortwave
approaches and moves through late Saturday into Sunday, leading to
increased chances for showers and thunderstorms. Rain chances lower
by Sunday evening and on Monday. Chance increase once again on
Tuesday, with another frontal passage.

Hot and humid through the period. Highs generally top out in the mid
to upper 80s, to around 90 in the urban metro. With the moist air
mass in place, dew points in the 70s, heat indices will likely get
into the low 90s for much of the region this weekend. Low chance of
heat headlines being needed this weekend.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
A weak frontal boundary will begin to approach from the northwest
this afternoon and evening.

Winds will become WSW-SW into the afternoon 10-15 kt. Afternoon
sea breeze enhancements are likely at KJFK, KISP, KBDR, and
KGON. Winds become light once again tonight.

A shower or thunderstorm is possible at KSWF late this afternoon and
evening. Any of this activity is expected to stay well NW of the NYC
metro terminals.

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

The sea breeze could reach KLGA in the late afternoon/early
evening.

An occasional gust 15-18 kt is possible at KEWR this afternoon.

OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...

Thursday: Chance of afternoon showers/thunderstorms with MVFR.

Thursday night and Friday: Showers/thunderstorms likely with MVFR,
IFR possible at times.

Friday night: Chance of evening showers/thunderstorms, then MVFR or
lower conditions possible.

Saturday: MVFR or lower possible in the morning, otherwise VFR with
a chance of showers/thunderstorms in the afternoon and evening.

Sunday: Chance of afternoon/evening showers/thunderstorms with MVFR.

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

&&

.MARINE...
-- Changed Discussion --
Conditions on the waters remain below SCA thresholds through
Thursday. Then, Thursday night through Friday night, SCA
conditions will become probable on the ocean while the non-ocean
waters remain below SCA thresholds.

Generally looking at sub-SCA conditions this weekend into the
first part of next week.
-- End Changed Discussion --

&&

.HYDROLOGY...
-- Changed Discussion --
Multiple rounds of showers and thunderstorms are expected
Thursday night through Friday night. Heavy rain will be
possible especially Thursday night through Friday. Marginal
threat of flash flooding with a higher chance of nuisance and
minor flooding of poor drainage areas. Friday the area has
marginal to slight risk of flash flooding.

Additional rounds of showers/tstms expected this weekend.

With all the rainfall we have recently received and flooding we
have had, the threat of additional flooding is possible
depending on where the heavy downpours occur.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
There is a moderate risk of rip current development at all the
ocean beaches through Thursday. Southerly winds with southerly
swells of 2-3 ft will be in place across the ocean beaches
during this time period.

&&

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

&&

$$
SYNOPSIS...BC/JM
NEAR TERM...BG/JM
SHORT TERM...JM
LONG TERM...BC
AVIATION...IRD
MARINE...BG/BC/JM
HYDROLOGY...BC/JM