465
FXUS61 KOKX 140939
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
539 AM EDT Fri Jun 14 2024
.SYNOPSIS...
A cold front will move through the area this evening with high
pressure building in from the northwest behind it. High pressure
becomes centered over the area Sunday morning and moves offshore by
Sunday evening. The high remains in control through late next
week.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
The forecast remains on track this morning. A few isolated
showers have popped up just south of Long Island, so have
continued the slight chance of showers for early this morning.
This activity will likely be confined to Long Island.
High pressure has now shifted well offshore as a cold front
approaches from the west. The front is currently over the Great
Lakes and approaching western NY as the associated surface low
tracks through southeast Canada. Aloft, multiple shortwave troughs
are rotating around the broader trough over the northeast US.
We are still on track to potentially see strong to severe
thunderstorms this afternoon and evening. The latest SPC outlook
remains similar to the previous outlook. NYC north and west are
in a slight risk and the rest of the area is in a marginal
risk.
Before any potential severe weather, showers will be possible early
this morning, mainly across Long Island. This looks to be associated
with weak warm advection ahead of a midlevel shortwave. Then,
multiple CAMs show some convective activity entering the Lower
Hudson Valley by mid morning. This activity looks to spark up north
and west of our area associated with a weak shortwave that will pass
north of us and a pre-frontal trough. Not too confident in this
activity and although thunder is possible, any storms will likely
stay below severe limits.
Later this afternoon into the evening is the most likely timing
of any severe weather as a stronger shortwave approaches aloft
as well as a cold front at the surface. A moist southerly flow
will bring dewpoints into the upper 60s by the afternoon and
mostly sunny skies will help bring surface temperatures up to
the mid to upper 80s for most. This will result in SBCAPE values
around 1000-1500 J/kg for NYC north and west. 0-6 km shear is
expected to max out around 35 to 40 kt, also for NYC north and
west. This environment can support severe thunderstorms capable
of producing damaging winds and large hail. While discrete
convection cannot be ruled out, the most likely form will be
clusters or a broken line. Given the moist environment and
skinny CAPE profile, heavy rain is also possible in any showers
or thunderstorms. See hydrology section below. It is possible
the severe threat becomes limited by any activity that happens
earlier in the day and will depend on if/when that occurs and if
we can destabilize after that. The severe threat is also lower
across eastern areas as the storms will likely weaken as they
reach the marine environment as is usual this time of the year.
The area will likely be dry by the early morning hours on Saturday.-- End Changed Discussion --
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
After an active Friday, the weekend is expected to feature plenty
of sunshine and quiet weather. High pressure slowly builds in behind
the departing cold front as heights rise aloft with an upper level
ridge building over the eastern US. The airmass that will build in
will be cooler and drier. Dewpoints will be in the 40s and 50s both
days, withs highs in the 70s to low 80s. This will give the air a
comfortable feel. We could actually drop to the upper 40s at the
usual cool spots Saturday night as radiational cooling conditions
look ideal.
The center of the high moves offshore by Sunday evening and a return
flow sets up.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
**Key Points**
* Increasing confidence in a prolonged heat wave mid to late next
week. Heat indices may approach or exceed 100F at times,
especially Wednesday through Friday.
* Heat indices greater than 90 are expected as early as Tuesday,
gradually expanding and increasing through the end of the week.
Surface high pressure gradually shifts overhead and offshore on
late Sunday as a large mid and upper level ridge continues to
build over the Eastern CONUS. The surface high pressure
positions itself over the Western Atlantic, allowing for a
persistent southwest to south flow over the area, advecting both
lower level moisture and warm air into the area.
The building ridge amplifies further into the middle to end of the
week, allowing for the development of a close to 600dm ridge over
the Northeast US and SE Canada. A ridge of this strength for mid-
late June over the area would be highly anomalous, though there
still remains uncertainty as to how strong it becomes.
Temperatures at 850mb from Tuesday through at least Friday will
be 18-21C allowing for surface temperatures to reach into the
90s and possibly approaching 100 degrees toward the end of the
week for western portions of the area away from the immediate
coastline. Heat indices may be slightly higher given a SW/S flow
advecting higher moisture into the area. While details as to
the extent of the heat will come into focus as we approach early
next week, this will very likely be the first heat wave of the
season with heat headlines eventually being needed for at least
a portion of the area.
Given the potential duration of the heat, it`ll be important to take
precautions to protect one`s health, particularly those without
effective cooling and/or adequate hydration. Some heat-sensitive
industries and infrastructure will likely be impacted by the extent
of this heat as well.
&&
.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
A cold front approaches from the NW today, preceded by a prefrontal
trough. Both will make their way through the area late afternoon
into the evening hours.
VFR expected through this afternoon. MVFR or lower conditions are
likely with any showers and/or thunderstorms today and tonight. Best
chance of TSRA 18-22Z Friday at KSWF, 21-01Z across the city
terminals, and 22-02Z at the eastern terminals. Heavy rain and gusty
winds possible in any TSRA. SHRA continue Friday night through 6Z.
Cigs may drop to MVFR or lower for a period before the Saturday
morning push.
Southerly winds 10 kt or less at all terminals overnight. The
terminals east of NYC may see gusts return 13-16Z at 15-20kt.
Stronger winds are possible in vicinity of TSRA this afternoon and
evening. Wind direction could also become tricky in the afternoon as
the pre-frontal trough moves into the area.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
A spotty shower is possible at the coastal terminals 09Z-15Z Friday.
Confidence is too low to put in TAF at this time.
The main band of showers and thunderstorms Friday afternoon and
evening could vary by 1-2 hours. There also could be a few random
showers and thunderstorms ahead of this main band in the afternoon.
OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY...
Friday Late Night: MVFR or lower possible showers that may linger
into early Saturday morning. N winds behind the cold front may
briefly gusts up to 25kt.
Saturday through Tuesday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
A southerly flow will occasionally gust up to 25 kt this
afternoon, otherwise winds and waves are expected to remain
below SCA conditions through early next week.
There is potential for showers and thunderstorms this afternoon
and evening, with the possibility of some being strong to
severe.
&&
.HYDROLOGY...
The entire area is now in a marginal risk of excessive rainfall.
Expecting mostly minor urban poor drainage flooding, but localized
flash flooding cannot be ruled out. Although rain will be heavy at
times, the progressive nature of the thunderstorms is expected to
keep flooding more minor. Probabilities of seeing 1 inch in 1 hour
remain low. Average storm total rainfall amounts will be between
half an inch and 1 inch, with locally higher amounts possible.
&&
.TIDES/COASTAL FLOODING...
There is a high risk for rip current development along Atlantic
facing beaches today with southerly flow 15 to 20 kt along the
shoreline and surf up to 4 ft expected.
Conditions begin to improve by Saturday, with a moderate risk
forecast as winds shift offshore.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Risk for Rip Currents through this evening for NYZ075-080-081-
178-179.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JT/MW
NEAR TERM...JT
SHORT TERM...JT
LONG TERM...MW
AVIATION...MW
MARINE...JT/MW
HYDROLOGY...JT/MW
TIDES/COASTAL FLOODING...JT