000
FXUS61 KOKX 042325
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
725 PM EDT Fri Aug 4 2023
.SYNOPSIS...
A cold front will move through the area tonight. High pressure
returns for the weekend. A frontal system impacts the area
Monday into Tuesday. High pressure briefly builds in Wednesday,
with another area of low pressure potentially moving through by
late week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
-- Changed Discussion --
Trimmed back PoPs to chance (40-50%) into tonight given the
lower coverage of the showers and thunderstorms across Upstate
NY. Still can`t rule out an isolated strong to severe
thunderstorm as a cold front advances toward the region,
particularly for the lower Hudson Valley, but chances will
continue to decrease into this evening with loss of heating. A
Severe Thunderstorm Watch remains in effect for Orange and
Putnam Counties until 8 PM this evening. With these noted
changes, forecast remains on track and previous discussion
follows.
SBCAPE combined with effective bulk shear values of 30-35 kt
could result in storms producing damaging wind gusts and
isolated large hail. The thinking right now is that any activity
will weaken once making it through northern portions of the
Lower Hudson Valley and then continue below severe criteria.
Heavy downpours are also expected with these storms. Latest MRMS
radar estimates show isolated areas that received a quick 0.5
to 1 inches in an hour. WPC currently has the area in a marginal
risk for excessive rainfall. Flash flooding is not expected and
minor poor drainage flooding is the main threat. Out ahead of
the broken line of storms, very isolated warm advection showers
are ongoing across Long Island and CT.
Showers and thunderstorms will end from west to east tonight,
exiting far eastern locations around 4-6 AM Saturday morning. Some
slightly cooler and drier air will advect in behind the front, but
not expecting a big airmass change. Lows will be in the upper 50s to
upper 60s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Upper level trough axis shifts offshore early Saturday morning
and the flow aloft becomes more zonal. At the surface, high
pressure noses in from the northwest as the cold front departs
offshore.
The warmest day in about a week is expected on Saturday, with
temperatures back to, or just above, normal. Highs will be in the
low to mid 80s. The air will still have a comfortable feel to it
with dewpoints in the upper 50s to lower 60s. Given subsidence
through the column, dry are sunny conditions are expected.
Temperatures Saturday night will be limited as high clouds spread
over the area from the west. However, slightly below normal lows are
expected, in the upper 50s across the interior and lower 60s to
lower 70s elsewhere.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Weak ridging is in place on Sunday as surface high pressure drifts
through the Northeast and offshore. This should maintain dry
conditions through the day, though cloud cover builds ahead of
an approaching low pressure system moving into the Great Lakes.
By Monday, the attendant warm front likely lifts through the region,
with increasing rain chances as it does. Still some uncertainty
with exact timing and placement of the surface features, but
depending on where the warm sector sets up which will better
determine the thunderstorm threat. At this time, a few thunderstorms
are possible ahead of the trailing cold front late Monday or
early Tuesday, with a relatively low severe threat. WPC currently
has a marginal risk for excessive rainfall across northern NJ
and portions of the lower Hudson Valley. Fortunately, the system
appears to be progressive enough to limit a more significant
flood threat.
High pressure builds in late Tuesday into Wednesday, then offshore
with a return southerly flow setting up. Another area of low
pressure may track east into the Great Lakes by Thursday, bringing a
return to rain chances into late next week.
Temperatures will remain relatively seasonable through the period,
with highs generally in the low to mid 80s, and daytime dew pts in
the 60s. Primarily followed the national blend of model guidance for
this update.
&&
.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
A cold front will move across the terminals tonight followed by high
pressure for Saturday.
Some MVFR ceilings are possible this evening into tonight before VFR
prevails behind the cold front through Saturday. Chances for showers
and thunderstorms have lowered this evening. While a shower or
thunderstorm cannot be completely ruled out, coverage is expected to
be much lower. The highest chance of a thunderstorm this evening is
at KSWF and this is where a VCTS remains from 01-03z. Based on
latest trends will have a VCSH this evening for NYC and Lower Hudson
Valley terminals. This may still be too aggressive as any showers
may end up isolated. A shower is possible with the cold front
passage across Long Island and southeast CT, but coverage appears
too limited to include in the TAF at this time.
S-SW winds 10-15 kt to start will weaken and fall below 10 kt this
evening. Winds will shift to the NW-N with the cold front passage
overnight/early Saturday morning. NW-N winds under 10 kt expected
through the day Saturday with afternoon sea breezes most likely at
KJFK, KISP, KBDR, and KGON.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Low chance for a thunderstorm this evening. Coverage too limited to
include in the TAF.
Flight categories may fluctuate between MVFR and VFR early this
evening. Ceilings around 030 overnight could end up VFR.
Timing of wind shift to the NW may e off by 1-2 hours.
OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY...
Saturday afternoon through Sunday: VFR.
Monday: Mainly VFR.
Monday night: Showers/tstms likely with MVFR or lower cond.
Tuesday-Wednesday: Mainly VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90ith cold fropa
and veer N after 12Z-13Z.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Thunderstorm chances have decreased this evening and have
removed TEMPO 01-04z, but VCSH is still expected.
Timing of wind shifts tonight may be off by 1-2 hours.
OUTLOOK FOR 18Z SATURDAY THROUGH MONDAY...
Saturday afternoon through Sunday: VFR.
Monday: Mainly VFR.
Monday night: Showers/tstms likely with MVFR or lower cond.
Tuesday: Mainly VFR.
Wednesday and Thursday: VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
-- Changed Discussion --
Winds and waves will remain a bit elevated ahead of a cold
front through this evening. Though winds should largely stay
below 25 kt, an occasional gust to 25 kt is possible. Ocean
seas should remain around 4 ft. Winds and seas subside behind
the cold front passage late tonight into Saturday morning.
Winds and seas will remain below SCA levels across the forecast
waters Sunday through Monday. Increasing southerly flow ahead of a
frontal system Monday may produce marginal SCA wind gusts and seas
on the ocean into early Tuesday. Sub-SCA conds return to all waters
for the middle of next week.-- End Changed Discussion --
&&
.HYDROLOGY...
-- Changed Discussion --
Isolated showers and thunderstorms through this evening may
produce locally heavy rainfall mainly north and west of NYC.
Minor nuisance and poor drainage flooding is possible.
There are no significant hydrologic concerns from Sunday through the
late next week.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
There is a moderate risk of rip current development along Atlantic-
facing beaches Saturday and Sunday with a 3 ft and 7 sec period
S swell.
The threat of minor coastal flooding has ended. All locations in the
South Shore Back Bays should remain just below minor levels tonight
and then continue to lower the next several days.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DR/JT
NEAR TERM...DR/JT
SHORT TERM...JT
LONG TERM...DR
AVIATION...DS
MARINE...DR/JT
HYDROLOGY...DR/JT
TIDES/COASTAL FLOODING...