265
FXUS61 KOKX 241724
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
124 PM EDT Sat Aug 24 2024
.SYNOPSIS...
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High pressure slowly weakens this weekend and works offshore.
A wave of low pressure approaches from the north Monday and
moves across Monday night. High pressure briefly builds into the
region Tuesday and then east on Wednesday. A cold front moves
through Wednesday Night, with Canadian high pressure building in
for late week. A frontal system approaches for the weekend.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Zonal flow will help steer nudge high pressure offshore today.
The pressure gradient remains weak, allowing for surface flow to
remain light with mid level flow slowing down as well. High
pressure will slowly weaken offshore.
Dry conditions with 850mb temperatures forecast to increase between
1 and 2C compared to the previous day. With few clouds, high
temperatures are forecast to be slightly warmer than the
previous day, ranging mainly within the lower 80s with mid 80s
for parts of NYC and NE NJ. Used NBM for the high temperature
forecast today.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
A mid level shortwave with its associated positive vorticity
advection is forecast to move across the region Sunday. This
shortwave moves east of the area Sunday night but will be followed
by an even stronger shortwave moving in Monday into Monday night.
This shortwave and associated vorticity maximum are expected to the
south and east of the region by early Tuesday.
At the surface, high pressure will continue to slowly weaken
offshore tonight into Sunday. Dry with mostly clear sky
conditions tonight into early Sunday. A daytime trough looks to
develop Sunday afternoon into Sunday evening, possibly causing a
pop up a shower or thunderstorm for parts of the interior.
Overall, a mainly dry day for Sunday is expected.
The pressure gradient continues to remain weak Sunday night. An area
of surface low pressure approaches from the north Monday, eventually
moving across Monday night. This will have more positive vorticity
advection in the mid levels. NAM indicates more CAPE than the GFS
Monday into Monday night, so there will be increasing chances of
showers and thunderstorms. NAM indicates near 25-30 kt of 0-6 km
bulk shear along with potentially up to near 2000 J/kg of CAPE, so
there is the possibility for some thunderstorms to be strong.
With a substantial period of onshore flow by the time of Sunday
night into early Monday, forecasting for patchy fog to develop
across much of the interior where more nocturnal cooling will take
place.
Temperatures for tonight are still expected to drop into the upper
50s for rural sections of the area and parts of the interior with
the rest of the region ranging from the low to upper 60s. The low
temperatures for tonight into early Sunday morning used an even
blend of NBM and MOS consensus.
Temperatures are forecast to be quite similar for both Sunday and
Monday as well as their respective nights. Daytime highs are
forecast to be mostly in the low to mid 80s with upper 80s for parts
of NYC and NE NJ whiles nighttime lows are forecast to be more
within the 60s. NBM was used for the temperature forecast.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
NE troughing slides east on Tuesday, with flattening upper flow
(possible shortwave ridging) on Wed. Another northern stream
shortwave drops into the NE Wed Night/Thu, although there is model
spread on how amplified this shortwave is. Then general model
agreement on southern ridging building back towards the region for
the late week, before strong northern plains shortwave slide east
through the Great Lakes towards the NE for the weekend. There is
typical Day 5-7 model spread on timing/amplitude of ridging and
subsequent troughing for late week/weekend.
At the surface, good agreement on high pressure building in from the
west on Tue in wake of departing surface low/shortwave, with warm
front passing north Tue Night/Wed Am. Dry and slightly above
seasonable temps on Tuesday with rising heights and WAA aloft,
giving way to a potential quick hit of late summer heat/humidity on
Wednesday. Potential for one day of heat indices into the mid to
upper 90s for NYC/NE NJ and surroundings. There is also potential
for late Wednesday aft/eve shra/tsra activity depending on strength
of shortwave.
A return to dry, comfortable Tds and seasonable temps on Thu/Fri as
Canadian high pressure builds in.
Next chance for unsettled weather for the weekend as frontal system
associated with northern plains trough approaches.
&&
.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
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VFR through the TAF period. Light and VRB/NW winds becoming
S/SW with local sea breezes after 19Z.
Light S/SW to variable flow tonight veering to light W by Sunday
AM. Light W/SW winds then become S with afternoon sea breezes
once again.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of the seabreeze this afternoon and again on Sunday may
be off by an hour or so.
OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...
Sunday: VFR. Light W/SW winds, becoming S/SW with afternoon
seabreeze.
Sunday night: VFR. Slight chance of evening shra/tsra for KSWF.
Monday: Chance for aft/eve shra/tsra. MVFR or lower possible.
Tuesday: VFR.
Wednesday and Thursday: VFR. Chance of MVFR or lower in aft/eve
shra/tsra.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
With a weak pressure gradient over the area, sub-SCA conditions
are expected through the middle of next week. Low potential for
marginal ocean SCA seas Thu/Fri depending on strength of NE
flow in wake of cold front.
&&
.HYDROLOGY...
There are no hydrologic concerns through the period.
&&
.TIDES/COASTAL FLOODING...
There will be a low rip current risk today, with more of a
moderate risk level Sunday with an increasing S to SSW wind
Sunday afternoon. Surf height is not expected to be above 2 ft
throughout the weekend.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
UPDATE...JM/DW
AVIATION...DBR