000
FXUS61 KOKX 181951
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
351 PM EDT Sun Jun 18 2023
.SYNOPSIS...
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Low pressure will continue moving northeastward across the
Canadian Maritimes through tonight. A weak cold front moves
through this evening and then east of the region later tonight.
Another weak front moves into the area Monday into Monday
night. This surface trough lingers nearby Tuesday as high
pressure builds south from New England. The high moves overhead
Wednesday, before shifting offshore into late week. Low pressure
to the south may impact the area this coming weekend.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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Low pressure continues to move northeast through the Canadian
Maritimes through tonight. Aloft, the cutoff upper level low
will follow a similar track with a trough on the backside of the
low remaining across the area. However, this trough will become
weaker with slight height rises continuing into tonight. The
trough on the numerical weather prediction models plan views
appears to become relatively flatter with time. The forecast
models show an area of mid level positive vorticity advection
moving into the local region for this evening before more
negative vorticity advection takes place late tonight into
early Monday.
The pressure gradient will become weak, allowing for sea breeze
circulations to develop towards the latter half of this
afternoon into early this evening. A weak cold front, weak
trough move through this evening and move east of the area
later tonight. Winds overall tonight will eventually become
light and variable in direction.
Large scale numerical weather prediction model precipitation
forecasts keep conditions dry but mesoscale models convey isolated
to widely scattered shower development into this evening. These
models include the HRW NSSL, HRW ARW, HRW FV3, HRRR as well as
the NAM Nest. There will not be as much favorable lift jet
dynamics and less instability than yesterday so do not think
there will be enough vertical lift for thunderstorm development.
However, with less than 1000 J/kg of surface CAPE and cold pool
aloft, some shower development is forecast along the higher
terrain and then subsequent outflow boundaries colliding with
sea breeze boundaries could initiate further shower development
to the south with some lingering shower activity into this
evening.
Some of the mesoscale models have not verified with their
reflectivity forecasts thus far. Will keep POPs slight chance
for rain showers into this evening.
Dry conditions expected overnight with more subsidence taking
place aloft.
Temperatures will remain near normal for lows late tonight.
Forecast lows tonight are mainly in the mid 50s to mid 60s.
Lows get into the lower 50s for some interior locations and
possibly for some parts of the Pine Barrens as well while some
parts of NYC will have lows more in the upper 60s for tonight.-- End Changed Discussion --
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
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The local area will still be under the upper level trough with
periodic shortwaves moving along the southern end of the trough.
One moves through Monday night. The trough and shortwaves will
still be present despite some slight height rises. There will
not be much strength to the shortwave but enough to warrant the
mention of the possibility of rain showers Monday afternoon
through Monday night. Models also indicate that low level
instability will be a little higher than the previous day so
added in a slight chance of thunderstorms across the most
interior parts of the area within the Lower Hudson Valley into
Southwest CT.
At the surface, weak high pressure to the north and east allows
for an easterly flow to develop. The forecast models also
depict some trough development across the interior that could
further focus convergence and allow for rain shower development
late in the afternoon and into Monday night. The trough remains
in the vicinity of the region Monday night. The easterly flow
will be greater along the coast and less inland, allowing for
relatively warmer temperatures across the interior with greater
convergence as well. The easterly flow slightly weakens Monday
night.
Temperatures Monday trend slightly cooler along the coast
compared to the previous day with more maritime influence but
will be nearly the same inland compared to the previous day.
Used NBM and a consensus of MOS for the forecast highs. For
Monday night, used a blend of consensus raw model temperatures
and NBM to convey a less vast range of lows, generally in the
upper 50s to lower 60s, a little below normal for this time of
year. The airmass will be transitioning to more of a cooler
maritime airmass.
The area where showers will be more probable is where the HRRR
was showing some increase in near surface smoke for Monday
afternoon into Monday evening. Because of the increased chances
for showers, do not think concentrations of smoke would be much
considering the wet deposition from the rain showers.-- End Changed Discussion --
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
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Troughing over New England finally exits as ridging over the Upper
Great Lakes builds and gradually shifts east this week.
A surface trough lingers nearby to start the period, with a weak
shortwave passing through New England providing some additional
energy. This weak forcing and instability (MUCAPE values around 500
J/kg) may support the development of a few scattered showers or
thunderstorms across the interior in the afternoon, though most
should remain dry.
Upper ridging begins to shift east Wednesday into Thursday as
surface high pressure tracks south into the region, maintaining dry
conditions. With the east to southeast flow, a relatively cool air
mass will be across the region through Thursday; highs mostly in the
70s. The ridge and surface high move offshore into the start of the
coming weekend, with a return flow allowing temperatures to return
to more seasonable levels, with humidity also on the increase.
Guidance continues to keep low pressure to the south late this week,
though rain chances begin to climb this weekend with increasing
moisture on the S/SW flow. Capped PoPs at high chance (50%) given
inherent uncertainty at this stage. Otherwise, with subtle
adjustment, national blended guidance was followed for this
update.-- End Changed Discussion --
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
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Low pressure tracks slowly northeast through the Canadian
maritimes thru tonight. A weak backdoor cold front pushes
through the area this evening, with weak high pressure builds
into the region in its wake.
VFR.
Weakening NW winds (generally right of 310 magnetic) 10 kt or less,
giving way to late-day sea breezes at KJFK/KISP/KBDR/KGON. Low
probability of reaching the remaining city terminals and KHPN around
00z. Winds become light and variable this evening, and then NE
around 5 kt overnight. NE winds less than 10 kt for morning push,
giving way to hybrid SE sea breeze late morning into early
afternoon, pushing through all terminals except KSWF.
Haze aloft possible from Canadian wildfires Monday morning, no
issues anticipated at ground level.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Weakening winds wavering on either side of 310 magnetic
(generally just to the right) this afternoon, giving way to sea
breeze at JFK by 21z(timing may be off by an hour or so). Low
probability for sea breeze at KLGA/KEWR/KTEB, and if so, aft 00z.
Winds shift to NE around 5 kt aft 00z. NE winds 10kt or less for
morning push.
Sct-Bkn cigs of 050-060 into eve push.
OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...
Mon aft - Tue Night: VFR. A chance of showers with isolated
thunderstorms, well north and west of the NYC/NJ terminals.
E winds 10 kt or less. Low prob for MVFR cigs Mon Night/Tue AM
for coastal terminals, and Tue Night/Wed AM.
Wed - Fri: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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The pressure gradient across the forecast waters will remain
relatively weak through Monday night, allowing for sub-SCA
conditions to continue.
With high pressure dominating Tuesday into late in the week, winds
and seas are expected to remain below SCA levels across the forecast
waters.-- End Changed Discussion --
&&
.HYDROLOGY...
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Any rain showers tonight as well as Monday into Monday night are
not expected to result in any hydrologic impacts. Rainfall
amounts are expected to remain less than a quarter of an inch on
average.
No hydrologic impacts are expected through the end of next
week.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
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There is a low risk of rip currents Monday for all Atlantic facing
beaches with 2 ft waves and 7 second or less dominant periods
expected.
There is a moderate risk of rip currents on Tuesday for all Atlantic
facing beaches with 2-3 ft waves and 7 to 8 second dominant periods
expected.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JM/DR
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...DR
AVIATION...NV
MARINE...JM/DR
HYDROLOGY...JM/DR
TIDES/COASTAL FLOODING...