000
FXUS61 KOKX 082345
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
745 PM EDT Sat Jul 8 2023
.SYNOPSIS...
A frontal boundary will remain nearly stationary near the NJ/PA
border through tonight. A cold front approaches Sunday with a wave
of low pressure developing over the Mid Atlantic states late Sunday
into Sunday night. The low pressure system and cold front head east
of the area on Monday, with weak high pressure gradually build in
from the south and west. The center of high pressure moves across
Tuesday night into Wednesday. High pressure then moves out into
the Atlantic for the latter half of the week. Low pressure and an
associated cold front approach the area towards late in the
week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
-- Changed Discussion --
Shwrs and tstms have decreased in coverage and intensity this
eve. Any additional activity thru the rest of the eve is
expected to be mainly isold.
Mostly cloudy conditions are then expected overnight. There may be a
bit more widespread low cloud development ahead of the approaching
shortwave. Patchy fog is also possible out east. Overnight lows are
expected to only fall into the upper 60s and lower 70s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
Biggest change in the short term was to issue a flood watch for much
of the CWA. Only exception was across Long Island, where there was a
lower confidence of flooding to occur.
Timing for the Flood Watch:
NE NJ/Lower Hudson Valley/NYC - 2pm Sunday until 6am Monday
Southern CT - 6pm Sunday til 2pm Monday
There was not much change in the overall pattern during the
short term period. A shortwave rounds the base of the large
upper trough on Sunday. The lingering stalled frontal boundary
remains just west of the CWA, or right along the far western
portions of the CWA with another frontal boundary approaching
the front west. 12z forecast models continuing to indicate a
frontal wave developing over the Middle Atlantic Sunday
afternoon and Sunday evening, which will interact with a highly
saturated airmass with PWATs at or above 2 inches. There are
still timing and placement differences with regards to the axis
of heaviest rainfall.
Overall, widespread moderate to locally heavy rainfall with embedded
thunderstorms are expected to develop along the approaching front
during the day on Sunday as it moves into the western portion of the
CWA. Most CAMs are fairly consistent on the progression of the
heaviest precip to remain in the western portion of the CWA (mainly
the Lower Hudson Valley and N NJ) prior to 6PM on Sunday. This will
be the primary concern for any flooding during the day on Sunday.
Moderate to heavy rain will then continue to move eastward into
Sunday evening and overnight as the intensity is expected to
generally lighten as instability decreases.
The overall synoptic set up is concerning due to the slow
moving front, frontal wave enhancing lift, and high PWAT air.
There continues to be indication convection will develop a train
over areas, increasing the flood potential. The amount of
instability is uncertain and may be maximized further south
across the Middle Atlantic. However, weaker instability may
still be enough to combine with the high PWATs and slow
moving/stalled frontal boundary to bring heavy rainfall.
WPC has placed much of the CWA in a slight risk for excessive
rainfall, and has included a moderate risk across the far western
sections of the CWA. The latest collaborated QPF Sunday through
Monday yields 2-3 inches of rain across the interior of the Lower
Hudson Valley and NE NJ with 1-2 across much of the remainder of the
CWA. As with most events, locally higher amounts will be likely.
The rainfall is expected to continue into Sunday night and possibly
into Monday, however there are some differences with the models with
just how quickly the precipitation exits the region. Some of
the models have rain lingering across at least the eastern half
of the CWA into Monday, while some models end the rain late
Sunday night with drier conditions for Monday. With the threat
of rain possibly continuing into Monday, have decided to keep
the flood watch going until midday Monday.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Mid level trough axis moves east of the area Monday night. Mid level
flow then transition to more of a zonal through with slight height
rises going through midweek. A less amplified mid level shortwave
moves across Friday with slight ridging resuming thereafter going
into the start of next weekend.
At the surface, low pressure moves farther northeast from southeast
of Long Island Monday evening to Northern New England into Gulf of
Maine vicinity by Tuesday morning. There is model uncertainty on how
fast this wave of low pressure exits and some model solutions have
it closer to the forecast region than others. Forecast has a chance
for showers and thunderstorms Monday evening into overnight but the
chance for thunderstorms will decrease overnight into early Tuesday
morning with the decrease in forecast elevated instability.
The center of high pressure makes its way across the local area
Tuesday night through Wednesday and then will be moving increasingly
offshore out into the Atlantic. Overall, weather mainly dry Tuesday
through midweek.
The next wave of low pressure along with a cold front will approach
Thursday into the start of next weekend. Chances for showers and
thunderstorms return to the forecast.
Forecast hottest day is Wednesday when forecast highs range from
mainly the upper 80s to lower 90s, about five degrees above normal.
Other days will not be as much above normal but still slightly above
normal for high temperatures.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
Frontal boundary remains west of the region into Sunday morning.
A cold front approaches Sunday afternoon, moving through the
region early Monday morning.
Showers have remained few and far between, and feel comfortable
removing from TAFs for the remainder of tonight. Brief MVFR or
lower cigs possible this evening, especially for coastal
terminals, otherwise mainly VFR through 6z Sunday, before
becoming MVFR overnight as stratus and possibly patchy fog
develop, with localized IFR stratus and fog into Sunday morning.
Then, mainly VFR Sunday with some lingering MVFR stratus in the
mid to late morning.
Showers and thunderstorms develop ahead of cold front approaching
Sunday afternoon, with rain and low cigs/vsbys chances
continuing into the overnight period. MVFR or lower likely at
times.
Winds will be mainly S-SE near 5-10 kt through the TAF period.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Low confidence on timing of MVFR conds late tonight into Sunday
morning.
Brief MVFR to possibly IFR possible in thunderstorms late
Sunday, with thunderstorm timing potentially off by several
hours.
OUTLOOK FOR 00Z MONDAY THROUGH WEDNESDAY...
Sunday night: MVFR or lower possible at times. Showers and a
chance of thunderstorms into the night.
Monday: MVFR or lower possible at times. Showers. A chance of
thunderstorms day into evening.
Tuesday and Wednesday: Mainly VFR.
Thursday. Mainly VFR. MVFR or lower possible at times. Chance of
showers, mainly afternoon into night. Chance of thunderstorms,
mainly afternoon into evening.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Conditions remain below SCA criteria through early next week
with a weak pressure gradient over the area.
Much of the long term period will maintain below SCA conditions on
all waters. For Thursday late afternoon into Thursday night next
week, winds and seas increase with marginal SCA conditions across
the ocean.
&&
.HYDROLOGY...
Flood watches in effect for Sunday into Monday with the potential
for the south to north training of showers and thunderstorms along a
slow moving frontal system. This could result in areas of flash
flooding. The greatest threat for flash flooding appears to be
across our far western sections of the CWA where WPC has placed a
moderate risk for excessive rainfall. Also, Some of our flashier
streams and rivers will be at risk of flooding.
Much of the rainfall is expected to be over by Monday night. Could
still see rainfall amounts near a half inch or less Monday night
especially with any lingering thunderstorms. Locally higher amounts
are possible. Otherwise, no significant widespread rainfall expected
mid to latter part of next week.
&&
.TIDES/COASTAL FLOODING...
-- Changed Discussion --
There is a low risk of rip current development for all ocean
beaches thru Mon.
Water levels are forecast to remain below minor flooding
benchmarks into early next week.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Flood Watch from Sunday evening through Monday afternoon for
CTZ005>012.
NY...Flood Watch from Sunday afternoon through late Sunday night
for NYZ067>075-176-178.
NJ...Flood Watch from Sunday afternoon through late Sunday night
for NJZ002-004-006-103>108.
MARINE...None.
&&
$$
SYNOPSIS...BC/JM
NEAR TERM...BC/JMC
SHORT TERM...BC
LONG TERM...JM
AVIATION...JM/DR
MARINE...BC
HYDROLOGY...BC
TIDES/COASTAL FLOODING...