000
FXUS61 KOKX 081149
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
749 AM EDT Tue Aug 8 2023
.SYNOPSIS...
A warm front northeast of the area will be followed by a cold
front for this morning into this afternoon. High pressure builds
in for tonight into Wednesday and then offshore Wednesday night.
This will be followed by a storm system on Thursday. High pressure
then returns for Friday and lasts into at least part of Saturday
before another system potentially impacts us later in the weekend.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LAPS instability several hundred J/kg across eastern sections of
the region. Thus far, convection has been lower coverage than
forecast but the coverage has been increasing over the past
hour. Still have chance thunder with showers likely across
Eastern Long Island as well as Southeast Connecticut.
Into early this morning, warm front will be just northeast of the
region, leaving the region within the warm sector. Still have
approximately 30 kt of 0-6km AGL bulk shear so some thunderstorms
could be strong to severe with main threat of strong gusty winds
especially with higher levels of CAPE mid to late this morning.
The mid level trough axis moves into the area from the west today.
The increase in positive vorticity advection and cold pool aloft
will keep shower and thunderstorm potential in the forecast. Clouds
will remain abundant in coverage overall today.
The cold front moves across from the morning into the early
afternoon hours as the main parent low moves into Northern New
England. This will act to focus convection more where there is
greater instability, especially for eastern sections of the region
out across Long Island and Southern CT. Also the upper level jet
streak gets enhanced farther south of the region and the local area
will be relatively in a location more favorable for the enhanced
lift in that left front quad of the jet streak.
With still approximately 30 kt 0-6km AGL bulk shear, these locations
with their higher low level instability could result in some strong
to possibly severe thunderstorms. Again the main threat would be
strong gusty winds.
Expecting the cold front to be east of the region by mid to late
afternoon, as westerly winds become gusty and advect in drier air.
The parent low will still be in Northern New England moving to the
northeast. Model BUFKIT soundings also show a prominent inversion
developing above 800mb which should really limit the instability and
thereby diminish the thunderstorm threat going through the remainder
of the afternoon. With the drier air, shower coverage will become
less and less and shift to just the interior which will be closer to
the higher positive vorticity and cold pool aloft with the
trough axis moving in.
Temperatures forecast were a blend of MOS consensus and the NBM,
with values ranging from the upper 70s to lower 80s. Forecast
dewpoints to start the morning are near 70 but by mid to late
afternoon will be lowering down in the 60s.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
For tonight, in the mid levels, a trough axis will be moving east of
the region with nearly steady height tendency with more of a zonal
flow setting up.
At the surface tonight, the low will be moving northeast out of
Northern New England and towards the Canadian Maritimes. Across the
local region, high pressure will build in from the south and west.
Dry weather is expected tonight. Subsidence will not be as strong
with zonal flow aloft and without ridging. However, with some
subsidence and positive pressure tendency, clouds are expected to
decrease through the night. The combination of partially clearing
skies and winds staying up within the boundary layer will lead to
temperatures not radiatively cooling effectively. NBM and consensus
of all guidance used for low temperatures, a less vast and
relatively warmer range staying mainly within the 60s.
For Wednesday, mid level ridging occurs but surface pressure remains
nearly steady as the center of high pressure stays south and west of
the area. Low pressure stays also in the Canadian Maritimes. Dry
conditions remain and do expect more sun with that subsidence aloft.
Breezy westerly flow also remains and will help provide a very warm
but not too humid day. Max temperatures forecast are well into the
80s but with dewpoints just in the upper 50s to lower 60s, heat
indices will not be a factor. Apparent temperatures will be nearly
the same as the actual temperatures.
For Wednesday night, the mid level ridge moves into the region and
eventually east of the region by early Thursday morning. At the
surface, high pressure will move east of the region and
offshore. This will allow for surface winds to become more
southerly. In addition, clouds will start to move in from the
west out ahead of the next low pressure system. Once again, not
optimal radiational cooling, with forecast lows ranging from the
low 60s to low 70s.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Low pressure tracking through SE Canada then drags a cold front
toward the forecast area. This along with the potential of a
weak offshore low passing nearby brings chances of showers and
maybe a thunderstorm Thursday into Thursday evening. High
pressure returns for Friday with a dry day, then low pressure
emerging from the northern Great Lakes Region is progged to pass
to our north Saturday night into Sunday. This will bring a
chance of showers and thunderstorms mainly from Saturday
afternoon through Sunday evening. The flow aloft may then become
slightly cyclonic on Monday, bringing a diurnal threat of a
shower or thunderstorm.
Temperatures through the long term period are expected to be near
normal with with high temperatures mostly in the lower and middle
80s.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Low pressure passes north of the area this morning, dragging a
cold front across the terminals.
Scattered showers and possibly a thunderstorm will impact the
terminals east of NYC through about 14Z Thereafter, an isolated
shower cannot be ruled out at the Lower Hudson Valley terminals
through this afternoon.
Occasional MVFR ceilings this morning before improving to VFR
by late morning early afternoon. Ceilings may vary back and
forth during this time.
Winds will start SW-S 5-10kt, veering to the W and increasing
to 15-20kt with gusts 22-28kt by early afternoon. A few higher
gusts to around 30 kt possible. W-NW winds will then be slow to
diminish Tuesday night.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely as ceilings vary from mainly VFR to at times
MVFR.
Onset of wind gusts this morning may be delayed by 1-2 hours.
OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
Wednesday: VFR. W wind gusts around 20 kt.
Thursday: VFR.
Thursday Night-Friday: Mainly VFR. Chance of showers and MVFR. A
slight chance of thunderstorms Friday afternoon.
Saturday: Mainly VFR. Slight chance of afternoon showers and
thunderstorms mainly for NYC north and west.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
SCA for the ocean goes through tonight and for east of Fire Island
Inlet on ocean goes until 14Z Wednesday. SCA on non-ocean waters
18Z this afternoon until 04Z Wednesday. Otherwise, sub-SCA on
non-ocean waters until 18Z this afternoon and late tonight into
Wednesday morning. For Wednesday afternoon through Wednesday
night, sub-SCA conditions for all waters.
Thereafter, mainly sub-SCA conds expected on all waters into late
week.
&&
.HYDROLOGY...
Occasional heavy rain and minor flooding possible, mainly
across eastern sections of the region for Eastern Long Island
and Southeast Connecticut through early this afternoon where
there could be more thunderstorm activity. Otherwise, mainly
dry for this afternoon and dry conditions tonight through
Wednesday night.
Heavy rain is possible late Thursday into Friday, but at this
time there remains too much uncertainty to determine any
potential hydro risk.
&&
.TIDES/COASTAL FLOODING...
A high rip current risk for all Atlantic-facing beaches expected
today as seas build to around 5 ft with gusty 15 to 20 kt winds.
Moderate risk of rip currents forecast at the ocean beaches on
Wednesday.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Rip Current Risk through this evening for NYZ075-080-081-
178-179.
NJ...None.
MARINE...Small Craft Advisory from 2 PM this afternoon to midnight EDT
tonight for ANZ331-332-335-338-340-345.
Small Craft Advisory until 10 AM EDT Wednesday for ANZ350-353.
Small Craft Advisory until 6 AM EDT Wednesday for ANZ355.
&&
$$
SYNOPSIS...JC/JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...JC
AVIATION...DW
MARINE...JC/JM
HYDROLOGY...JC/JM
TIDES/COASTAL FLOODING...