198
FXUS61 KOKX 222330
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
730 PM EDT Mon Jul 22 2024
.SYNOPSIS...
A series of weak areas of low pressure will pass near the
area tonight through Wednesday night. A cold front approaches
during Thursday and moves through Thursday night into early
Friday morning. High pressure builds in from the west Friday and
Saturday, then remains into the beginning of next week.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
With the first round of showers and thunderstorms having moved
through the region, and another round moving in from the south
to southwest updated timing and probabilities for this activity.
Locally heavy rain remains possible with any of the storms.
More widespread shower and thunderstorm activity is expected
overnight as a shortwave on the eastern side of an upper trough
will help induce a weak surface low over the Mid Atlantic. That
low will then track northeastward along a boundary located south
of the region, passing south of the area overnight. With
precipitable water values forecast to exceed 2 inches across
much of the southern half of the forecast area, moderate to
locally heavy rainfall is possible at times overnight. The HREF
shows relatively high probabilities (70 percent) of exceeding 1"
of rainfall in 3 hours across Long Island overnight, with a 10
percent chance of exceeding 3" of rain in 3 hours across far
southern and eastern portions of the island. The latter
threshold is typically a good indication of flash flooding
potential, but given the location of the highest probabilities
believe urban and poor drainage flooding is the more likely
outcome.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
Low pressure will move east of the area Tuesday morning, with
any lingering rain across eastern Long Island and southeast
Connecticut coming to an end by mid morning. This will result in
a predominantly dry day for most of the area, although given
the moist atmosphere can`t rule out a a pop up shower or
thunderstorm through the afternoon.
Precipitation chances then increase again Tuesday night into
Wednesday as another shortwave/weak surface low ride along the
stalled boundary. The highest chances will once again be across
southern and eastern portions of the area, and with continued
moist atmospheric profiles in place, periods of moderate to
heavy rain will again be possible. Overall the flash flood
threat appears to remain low during this time period, although
that will be somewhat dependent on where the heaviest rain falls
Monday night into Tuesday. This second round of rain looks to
linger a bit longer into the day on Wednesday, with unsettled
conditions continuing through the afternoon.
With a good deal of cloud cover in place temperatures will
remain near seasonal norms, with highs in the mid 80s and lows
in the upper 60s to low 70s.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
An upper level trough remains from the upper midwest into the
northeast Wednesday night as a weak wave of low pressure will be
moving just north or through the region Wednesday night. With
high precipitable water values remaining across the region any
thunderstorms will be capable of producing briefly heavy
rainfall. And, while the storms are expected to be rather quick
moving, with previous days of heavy rainfall, and convection
potentially tracking over the same regions, the area remains in
a marginal risk for excessive rainfall Wednesday night. The
upper trough amplifies into the mid Atlantic region Thursday as
a cold front moves southeastward. The upper trough axis shifts
east of the region Thursday night into friday morning with the
passage of the cold front. The marginal risk for excessive
rainfall will continue into Thursday with additional rounds of
moderate to heavy rainfall possible, however, precipitable water
values will be lowering slightly.
As the trough moves into the north Atlantic Friday into the
weekend, a highly amplified, and full latitude ridge will builds
into the mid section of the country and track to the east coast
through the weekend and off the coast Monday. With the chance
of a shortwave moving through the periphery of the ridge Monday
have increased probabilities to slight chance across the inland
areas Monday afternoon.
Daytime high temperatures Thursday through Sunday will be near
seasonal normals, and may be slightly above normal for Monday as
high pressure begins to shift off the northeast and mid
Atlantic coast. Overnight lows will be slightly above seasonal
normal Wednesday night, and then near normal for Thursday night
into Saturday night.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Low pressure develops south of the area and tracks northeast
just south of Long Island tonight. An associated frontal system
meanders just south of the area through Tuesday.
Mainly VFR with MVFR for coastal terminals. Scattered SHRA/TSRA
possible through this evening where brief MVFR is
possible. MVFR cigs spread to remaining terminals after 03Z. SHRA/TSRA
possible overnight with pockets of heavier rainfall possible
mainly east of the city terminals. Drier conditions expected Tue
but scattered SHRA/TSRA possible again later in the day. Have
kept out of TAFs for now due to limited coverage.
S Winds 10-15 kt diminishing early tonight. Variable wind
direction likely overnight with the low pressure in the
vicinity. Winds become N late tonight into daybreak Tuesday.
Winds S-SW around 10 kt Tuesday afternoon coastal areas.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
There remains uncertainty in wind direction tonight and early
Tuesday due track of the low pressure passing to the south of
LI. Amendments possible this evening with lower flight
categories as well as SHRA/TSRA.
OUTLOOK FOR 21Z TUESDAY THROUGH SATURDAY...
21z Tuesday: Improving to VFR.
Tuesday night through Thursday: MVFR or lower in SHRA/isolate
TSRA.
Friday: MVFR or lower possible in the morning with SHRA,
otherwise VFR.
Saturday: VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
A series of weak lows are expected to pass over or near the
waters through the day on Wednesday, although winds and waves
are expected to remain below Small Craft Advisory criteria.
With a weak pressure gradient over the area, winds and seas/waves
remain below Small Craft Advisory criteria Wednesday night through
Saturday night.
&&
.HYDROLOGY...
With a frontal boundary expected to linger over or near the
area and multiple waves of low pressure passing through, periods
of moderate to locally heavy rain will be possible through the
week. At this time, the risk of flash flooding is low, but can
not be ruled out. WPC has outlined the entire area in a marginal
risk of excessive rainfall for Tuesday through Friday.
Instances of minor urban and poor drainage flooding are more
likely.
The first period of moderate to locally heavy rain will be
tonight. The highest totals are expected to be across eastern
Long Island and southeastern CT (on average 0.5 to 1 inch). With
pwats near 2 inches, localized rates of 1 inch per hour are
possible.
The region will remain in a humid and unsettled pattern into
Thursday night with anomalously high precipitable water values.
There is a limited risk of localized flash flooding from any
thunderstorms that produce heavy rain.
&&
.TIDES/COASTAL FLOODING...
A moderate risk of rip current development at the ocean beaches
will remain this evening through Wednesday as a S to SE swell
continues.
Minor coastal flood benchmarks may just be touched at some
locations along the south shore bays of Nassau County tonight.
Water levels are expected to be slightly lower on Tuesday night
and will likely remain below minor flooding benchmarks.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...FEB/MET
NEAR TERM...FEB/MET
SHORT TERM...FEB
LONG TERM...MET
AVIATION...DBR
MARINE...FEB/MET
HYDROLOGY...FEB/MET
TIDES/COASTAL FLOODING...