000
FXUS61 KOKX 062027
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
427 PM EDT Sun Aug 6 2023
.SYNOPSIS...
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High pressure along the coast moves offshore tonight as a
frontal system approaches from the southwest. The system impacts
the region late tonight through Tuesday. A warm front associated
with the system will move through late Monday night with the
attendant cold front moving through on Tuesday. Behind the
frontal passage, high pressure gradually builds into the region
from the southwest midweek. The next low pressure system moves
through late Thursday into Friday, with potentially another
approaching to close the weekend.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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An amplifying trough over the Great Lakes early this evening
will send an initial area of upper lift and increasing
isentropic lift into the region tonight as a warm front well to
the southwest slowly approaches. With the upper support and
precipitable water values increasing to just over 2 inches late
tonight, there is the potential for period of moderate to heavy
rainfall with mainly showers. There is a possibility of nuisance
flooding overnight. The thunder potential early is minimal with
little to no CAPE and not surface instability. CAPE and
instability begin to increase toward Monday morning.-- End Changed Discussion --
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
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Once the initial energy moves through the rain will taper off
during the day Monday. Then another round of moderate to heavy
showers, with an increased potential for thunder, will occur
late Monday afternoon into Monday night as the upper trough
continues to amplify and moves into the northeast and mid
Atlantic regions. Precipitable water values remain around 2
inches. CAPE, instability, and sheer will be increasing late
Monday into Monday evening as the surface warm front moves into
the area Monday evening. Also, additional lift will be provided
by a 70-80kt upper jet, with the LF exit region crossing the
area. The Storm Prediction Center has the far western areas in a
slight risk with the main threat damaging wind gusts. And with
increased sheer and helicity there is a low chance of an
isolated tornado. Rainfall rates could approach 1"/hour Monday
night, with total rainfall 1 to 2.25 inches, and total maximum
amounts in a few locations could be as high as 3 to 4 inches.
For Monday into Monday night much of the area remains in a
slight risk for excessive rainfall. While widespread flash
flooding is not expected with flash flood guidance as high as
2 to 3 inches in 3 hours, and the rain falling over a longer
duration, isolated flash flooding is possible if the higher
rainfall rates and rainfall totals are realized.
The warm front lifts north of the area late Monday night into
Tuesday morning and chances of precipitation will be
diminishing. And as the associated cold front passes through
during the day precipitation may come to an end. However, the
upper trough axis will be moving into the region and the surface
low will be to the north and east, and wrap around showers will
be possible through Tuesday.-- End Changed Discussion --
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
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The trough axis shifts east of the region Tuesday night with
heights climbing into Wednesday. A tightened pressure gradient
develops as the low pulls into the Canadian Maritimes and high
pressure builds in from the southwest. This will keep winds
blustery into Wednesday; gusts may top 25 to 30 mph at times
through the afternoon before subsiding.
The weak high pressure pushes offshore Thursday and surface
flow backs SW as another shortwave trough swings east into the
Great Lakes region. This will send a frontal system through late
Thursday into Friday, and bring another round of showers and
perhaps a few thunderstorms. At this time, the bulk of Friday
and Saturday may remain mostly dry, before another shortwave
approaches late in the weekend increase PoPs once again.
Temperatures will remain relatively seasonable through the
period, with highs generally in the low to mid 80s. Dew pts drop
behind the frontal passage Tuesday, allowing for a bit lower
humidity on Wednesday, before increasing once again late week.
Primarily followed the national blend of model guidance for this
update.-- End Changed Discussion --
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
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High pressure continues to slide offshore this evening. A warm
front will slowly approach the area through Monday.
VFR conditions expected through tonight. There is now a
southerly flow at most terminals. The sea breeze should push
through KHPN shortly and KSWF should become southerly this
evening with the synoptic flow.
Moderate to heavy showers and MVFR cigs move into the area
early Monday morning. Thinking the best window for the heaviest
rain is around 08z-13z for the NYC terminals. Widespread thunder
is not expected, but can not rule out isolated occurrences and
have included a VCTS in the latest TAF. Showers could linger
through the late morning, but an improvement to VFR is possible
in the afternoon with SCT020 during a lull period.
Winds become more southeasterly late tonight and then will
remain there through Monday. Winds increase and by Monday late
morning afternoon the flow will be 10-13KT with gusts 17-22KT. A
few isolated gusts up to 25KT are possible especially at KJFK.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of showers early Monday could be a few hours off from
forecast.
Widespread thunder is not expected, but isolated occurrences are
possible early Monday.
Uncertainty in cigs early Monday. MVFR likely, but periods of IFR
can not be ruled out.
OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...
Monday Afternoon-Monday Night: Lull in shower activity possible
Monday afternoon and an improvement to VFR for NYC terminals
and KISP. Slight chance of thunderstorms. SE wind gusts 15-20 kt
Monday afternoon into Monday evening. Another round of heavy
showers/thunderstorms Monday night. Some storms could be strong
to severe.
Tuesday: MVFR or lower in showers and thunderstorms. SW wind
gusts up to around 20 kt Tuesday.
Tuesday night: Chance of showers and thunderstorms, mainly in
the evening north of NYC and CT terminals with MVFR or lower
possible. Otherwise, mainly VFR. Westerly wind gusts up to
around 20 kt.
Wednesday: VFR. W-NW wind gusts up to 25 kt possible.
Thursday-Friday: Mainly VFR. Slight chance of showers Thursday
afternoon. Chance of showers Thursday night into Friday. A
slight chance of thunderstorms Friday afternoon. MVFR possible
at times.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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Winds and seas remain below SCA levels across the forecast
waters tonight through Monday. With an increasing southerly
flow ahead of a frontal system Monday into Monday night
marginal SCA wind gusts and seas will be possible on the ocean
waters by late Monday night. With low confidence in SCA
conditions developing, and being late Monday night, will hold
off on issuing an advisory at this time. With the prolonged
southerly flow ocean likely build to SCA levels by Tuesday, with
gusts remaining under 25kt.
SCA conds are expected to linger on most waters Tuesday night
through Wednesday afternoon with west winds gusting 25 to 30 kt
at times. Ocean seas may remain elevated above 5 ft through Wed
evening before subsiding.
Thereafter, largely sub-SCA conds expected on all waters into
late week.-- End Changed Discussion --
&&
.HYDROLOGY...
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Multiple rounds of showers and thunderstorms are possible from
late tonight through Tuesday morning. The best chance for
localized to scattered flash flooding will be Monday night into
early Tuesday morning. Rainfall amounts of 1 to 2.25 inches are
forecast across the area with the potential for localized
higher amounts, possibly as much as 3 to 4 inches. The Weather
Prediction Center has placed most of the area in a slight risk
for excessive rainfall Monday/Monday night.
Heavy rain will be possible late Thursday into Friday, but at
this time there remains too much uncertainty to determine any
potential hydro risk.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
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There is a moderate rip current risk for all Atlantic-facing beaches
on Monday due to a strengthening southerly flow of 10 to 15 kt and
building seas. This threat increases to high for all beaches on
Tuesday as seas build to around 5 ft with gusty 10 to 20 kt
winds.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DR/MET
NEAR TERM...MET
SHORT TERM...MET
LONG TERM...DR
AVIATION...JT
MARINE...DR/MET
HYDROLOGY...DR/MET
TIDES/COASTAL FLOODING...DR