402
FXUS61 KOKX 070943
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
543 AM EDT Sat Sep 7 2024
.SYNOPSIS...
A cold front moves through the area this afternoon through this
evening. High pressure builds in thereafter. High pressure looks to
briefly weaken Monday night as a surface trough moves through. High
pressure then continues to build over the area Tuesday through
the end of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Light showers can be seen on radar moving through NYC and
northeast NJ. This light activity will continue this morning
ahead of the cold front. The heavier showers along the cold
front are still over central PA and likely wont enter western
portions of the area until late morning/early afternoon.
A deep upper level trough approaching from the west has now closed
off over the Great Lakes. The associated surface low was last
analyzed over southeastern Ontario, with a cold front extended down
through western NY and western PA. Meanwhile, offshore low pressure
well east of the area continues to head north towards Nova
Scotia. Whatever surface ridging is still lingering over the
area will completely weaken early this morning.
With the surface ridge weakening, a moistening southerly flow will
begin ahead of the approaching cold front. Skies will be mostly
cloudy to overcast much of the day. However, there will be some
subsidence over far eastern locations and some breaks of sun are
possible there through the early afternoon. On the other end of
the forecast area, a low level moisture axis stretches into the
area. With some weak lift through the column, the CAMs show
some light activity this morning over NYC, northeast NJ and up
into the Lower Hudson Valley. Kept PoP similar to previous
forecast, slight chance to chance of light showers through the
morning for those areas.
The cold front will likely reach western portions of the area early
this afternoon and pass east during the evening hours. Showers are
expected along the front, with a slight chance of thunderstorms.
Pwats look to be a bit lower than guidance was showing 24 hours ago.
This is due to the plume of the deepest moisture likely now not
making it to the area before the cold frontal passage and
instead passing to the south and east. Pwats now look to be
closer to 1.25 to 1.5. However, moderate to locally heavy
rainfall is still possible. As for thunder, keeping at slight
chance for now. If there is any thunder it will likely be along
a thin convective line and brief for any one location. While
some gusty winds are possible, severe thunderstorms are not
expected due to weak instability and only modest shear.
The whole area will likely be dry by midnight. A northwest flow
behind the front will bring in a cool and dry airmass. The
interior should be able to get down to the upper 40s tonight.
With the flow still around 10 kt, locations around NYC and Long
Island likely do not drop below the mid 50s.-- End Changed Discussion --
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
High pressure builds in at the surface, but an upper level trough
remains over the northeast. A dry and seasonably cool day is
expected on Sunday. Highs will only be in the upper 60s to low 70s
and dewpoints should drop into the low 40s in the afternoon with
deep mixing. Some 15-20 kt NW gusts are also possible.
Radiational cooling conditions look ideal on Sunday night. Went
closer to the MOS guidance and have low to mid 40s at the usual cool
spots. Upper 40s to mid 50s elsewhere.
The flow becomes more W/SW on Monday. An embedded shortwave in the
larger upper level trough looks to rotate through late Monday into
Monday night. The surface high briefly weakens as an associated
surface trough passes through. The latest global guidance does
show some light QPF, but given the dry airmass left forecast dry
for now, which was in line with the NBM. However an increase in
clouds is expected.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
Key Points:
* A dry stretch Tuesday through Friday.
* A warming trend with high temperatures above normal by week`s end.
Models continue to be in decent agreement with upper ridging
building in to the northeast on Tuesday and amplifying by week`s
end. At the surface, high pressure will continue to shift north
Tuesday through Friday resulting in an extended dry stretch of
sensible weather. Highs each day will be near or just above
seasonable, in the low to mid 80s. The urban corridor may be a few
degrees warmer on Thursday and Friday, in the upper 80s, under weak
westerly flow. Dewpoints will also be on the increase Thursday into
Friday, as southerly flow ramps up as the surface high begins to
move offshore.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
A cold front approaches and eventually passes through the terminals
on Saturday afternoon.
VFR early this morning with MVFR likely by the morning push. MVFR,
or possible IFR ,with early -SHRA potential. MVFR cigs continue
before all VFR after the frontal passage mid to late afternoon.
Showers anticipated mainly with the front, though thunder is
possible for NYC terminals and TEB/SWF/HPN.
Light SE winds increasing late in the morning/early afternoon to 10-
15 kts, G 18-22kt. Winds shift NW and remain breezy behind front
into the evening.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Prevailing MVFR timing may be 1-2 hours off. TSRA possibility is
uncertain, and timing may be off by an hour or two.
OUTLOOK FOR 00Z SATURDAY THROUGH WEDNESDAY...
Sunday-Wednesday: VFR. NW-W gusts around 20kt possible on Sun.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
A Small Craft Advisory is in effect across the ocean waters due to a
5 to 6 ft easterly swell around 10s. As offshore low pressure pulls
away, the swell will begin to decrease on Sunday. However, lingering
5 ft waves are possible through about 18s Sunday and have extended
the SCA until then. Winds stay below SCA criteria for the most part.
Gusts may briefly reach 25 kt with the passing of the cold front
this afternoon into the evening.
Winds and seas are then expected to remain below SCA criteria
through midweek, as the pressure gradient remains weak across the
region.
&&
.HYDROLOGY...
No significant hydrologic issues are expected through the end of
next week.
&&
.TIDES/COASTAL FLOODING...
There is a high risk of rip currents today as an easterly swell of 5
to 6 ft at 10s combines with an increasing southerly flow that peaks
out at 10 to 15 kt this afternoon. The risk drops to moderate on
Sunday. While the flow will be offshore, a short period wind wave
will combine with a decreasing easterly swell (2 ft at 10s) to allow
for at least a moderate risk of rip current development. This is
supported by the latest RCMOS guidance. RCMOS shows high for all
beaches today and then lowering through the day tomorrow, but
staying mostly in the moderate category.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Risk for Rip Currents through this evening for NYZ075-080-081-
178-179.
NJ...None.
MARINE...Small Craft Advisory until 2 PM EDT Sunday for ANZ350-353-355.
&&
$$
SYNOPSIS...DBR/JT
NEAR TERM...JT
SHORT TERM...JT
LONG TERM...DBR
AVIATION...DBR
MARINE...DBR/JT
HYDROLOGY...DBR/JT
TIDES/COASTAL FLOODING...JT