883
FXUS61 KOKX 300950
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
550 AM EDT Fri Aug 30 2024
.SYNOPSIS...
High pressure across New England will be slow to weaken and
retreat out into the Atlantic through tonight. A frontal system
approaches on Saturday, moving across the area Saturday night
into Sunday morning. A secondary cold front moves through late
Sunday into Sunday night. Thereafter, Canadian high pressure
builds in and will remain in control through at least the
middle of next week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Main area of showers along with a few thunderstorms, oriented
from NW to SE across the Lower Hudson Valley, NE NJ and into
the NYC metro, has been overachieving with rainfall. Even with
CAPE values less than 500 J/kg, PWAT and lift associated with
shortwave have produced pockets of moderate to heavy rainfall.
MRMS 1hr accum rainfall in Passaic county NJ showed 0.75-1"
between 4 and 5 am. Latest radar imagery show this axis of
translating east at about 10 to 15kt. Expect weakening as it
works into the ridge axis across eastern areas the next couple
of hours.
The best forcing shifts east later this morning with ridging
aloft approaching from the west. This would favor decreasing
rain chances and confining any showers to western portions of
the forecast area. However, the latest HRRR continues to show
scattered showers into the afternoon and mainly across LI and
CT. There is really no support from any of the other CAMs. Thus,
prefer to play this down and stay with a drier forecast. In
fact, drier air may win out enough for sunshine across SE CT and
eastern LI.
Highs today are forecast to top out in the lower to mid 70s,
which is about 7 to 10 degrees below normal. This will be
accompanied by an easterly flow with high pressure retreating
off the New England coast and a stalled frontal boundary over
the Mid Atlantic states.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
Expect a mainly dry night with an upper level ridge moving
across the area. As winds gradually veer to the SE, there could
be some weak low-level warm advection producing drizzle and/or
sprinkles. For the time, have left the mention out of the
forecast. This would be mainly near the coast. Low tonight will
be in the 60s, but closer to normal with the cloud cover and
increasing low-level moisture.
On Saturday, the upper level ridge departs to the east while
low-level ridging gradually loses its grip of the area. A well
advertised amplifying upper trough across eastern Canada and
the Great Lakes sends a series of frontal systems toward the
area, the first of which will move across the area late Saturday
into Sunday morning. The associated cold front weakens as it
approaches and may even get hung up or wash out just east of the
area Sunday morning. The best forcing and instability with the
cold front will stay mainly north and west of the area. The
approaching warm front passes through Saturday evening with
little activity. That being said, still expect some moderate
showers, possibly a thunderstorm, mainly Saturday night into
Sunday morning. Rainfall amounts will average from 0.25 to 0.50"
across the area, highest from NYC and points north and west.
Isolated higher amounts are possible with any stronger convection.
The day 2 outlook from SPC places western portions of the area,
including SW CT, western LI, and points west under a marginal
to slight risk of severe weather. The main threat being isolated
damaging winds. Mid level winds do strengthen Saturday night,
but instability is very marginal.
Showers linger into the morning hours Sunday, especially across
eastern LI and SE CT. The question then is how much can the
airmass recover ahead of a secondary cold front approaching the
area Sunday night. Right now, there looks to be too much dry
air, thus limiting the instability. Have kept an isolated threat
for a shower and/or thunderstorm Sunday afternoon with a pre-
frontal tough.
Temperatures warm up Saturday into Sunday. Highs on Sunday with
a SW flow and 85H temps around 15C will get into the lower and
middle 80s. A few locations around the NYC metro may get as high
as the upper 80s. It will also be more humid during this time
with dew points around 70.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A secondary cold front moves through Sunday evening, so slight
chance PoPs linger into Sunday evening for eastern areas.
Thereafter, Canadian high pressure builds into the area and brings a
cool and dry airmass to the region, with sunny conditions. On
Monday, dewpoints drop into the 40s during the afternoon into
evening hours and will stay there through midweek. Temperatures
will be below normal for early September during most of next
week.
&&
.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
High pressure across eastern Canada into coastal New England, and
the mid Atlantic will remain in place today as a surface trough
remains to the west.
Low confidence forecast with MVFR ceilings for western terminals,
which at times may briefly be VFR through daybreak today. Eastern
terminals such as KGON, KISP, and KBDR should be VFR, but at times
may briefly be MVFR through daybreak. Low confidence remains into
today with the ceiling forecast, and timing of any VFR conditions.
There is a chance that MVFR prevails most of the day.
Scattered showers are possible through daybreak and into early this
morning. An isolated thunderstorm may move through, mainly across
western terminals, such as the city terminals and KSWF, though
confidence is low.
An easterly flow persists through the forecast period, generally
less around 10 kt or less.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Low confidence in the timing and duration of showers and MVFR
conditions through daybreak and into the day today, with the
possibility of MVFR remaining much of the day.
OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY...
Friday night: MVFR, with a chance of VFR early.
Saturday: VFR. MVFR or lower possible in showers and thunderstorms
during the evening and overnight.
Sunday: Mainly VFR. Chance of showers, mainly in the morning.
Monday and Tuesday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Winds and waves will remain below SCA criteria through the
middle of next week. There could be a period of occasional 25 kt
gusts this weekend and on Monday with two cold frontal
passages, but this remains a low probability at this time.
&&
.HYDROLOGY...
Any hydro impacts over the weekend appear minimal at this time.
&&
.TIDES/COASTAL FLOODING...
The moderate risk of rip currents continues today with a
continued easterly flow. While winds will be a bit weaker, the
E to W sweep will enhance rip current activity along jetties and
groins.
On Saturday, the flow becomes southerly, just under 10 knots. 1 ft
long period southeasterly swell does build into the area, but
thinking low risk of rip currents for now with RCMOS showing
lowering probabilities into Saturday.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JP/DW
NEAR TERM...DW
SHORT TERM...DW
LONG TERM...JP
AVIATION...JP
MARINE...JP/DW
HYDROLOGY...JP/DW
TIDES/COASTAL FLOODING...