000
FXUS61 KOKX 152007
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
407 PM EDT Thu Jun 15 2023
.SYNOPSIS...
-- Changed Discussion --
Weak high pressure stays south of the region tonight. Low
pressure develops and approaches from the south and west for
Friday. The low center moves south of Long Island late Friday
night into early Saturday before moving northeast of the area
Saturday afternoon into Saturday evening. Low pressure will be
moving east of the area Saturday night into Sunday as high
pressure builds to the north. High pressure then briefly returns
Sunday night into Monday. Another low approaches from the south
Tuesday and remains nearby into Thursday.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
-- Changed Discussion --
For tonight, surface low pressure develops and approaches from
the south and west ahead of an upper level trough. Models show
mid level height drops will not be much across the area. Models
are conveying more of negative vorticity advection moving into
the area in the mid levels. So the lack of synoptic lift will
allow for a continuation of dry conditions and with subsidence,
clouds will decrease tonight.
Used a consensus of MOS for forecast lows, ranging from the low
to mid 50s across rural areas and inland locations to the upper
60s within parts of NYC.-- End Changed Discussion --
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
-- Changed Discussion --
For Friday, models indicate more significant mid level height
falls as the mid level trough approaches from the west. At the
surface, the pressure will likewise fall as a low pressure area
approaches from the DelMarva. South to southeast surface winds
will increase during the day and a large vertical layer of the
atmospheric winds will become more southerly. The increase in
moisture will increase layer precipitable water to near 1.25 to
1.5 inches according to the NAM and GFS. Showers develop and
move in with an increasing chance of thunderstorms late morning
into afternoon. The showers will be most widespread across the
western half of the forecast region.
While CAPE will be limited Friday, model values of 0-6km bulk shear
increases to near 20-30 kt, presenting an environment especially
with some low level veering of the winds, where some thunderstorms
could be strong. These thunderstorms could produce small hail and/or
gusty winds (up to near 40 to 45 mph) but at this time, looks
like most activity would stay below severe thresholds. Did
mention heavy rain with thunderstorms as the precipitable waters
increasing and not too rapid movement of showers considering
the winds within the first 10kft above the ground. With some
training of thunderstorm cells, could have repeated episodes of
heavy rain, and possible minor flooding.
The forecast highs Friday were from a combination of 1/2 consensus
of MOS and 1/2 NBM and lowered by 1, ranging mainly in the mid
to upper 70s.
For Friday night, mid level trough pushes farther south across
the region. At the surface, low pressure from the DelMarva moves
northeast, tracking south of Long Island. Showers will remain
in the area, widespread across the entire area in the evening.
There will be some elevated instability, so a chance of
thunderstorms will remain. Again, some thunderstorms especially
early, could produce locally heavy rain. Thunderstorm chances
diminish late, as elevated instability decreases.
The forecast lows Friday night were 3/4 consensus of raw model data
and 1/4 NBM, ranging mainly from the upper 50s to lower 60s.
For Saturday, the center of the cutoff mid level low moves into
the area from the north. At the surface, the low slowly moves
northeast, approaching near Cape Cod. Showers remain in the area
with a chance of thunderstorms with the cold pool aloft.
The forecast highs Saturday were 1/2 NBM and 1/2 consensus of raw
model data and lowered by 1, ranging mainly from the upper 60s
to lower 70s.-- End Changed Discussion --
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
-- Changed Discussion --
A upper closed low and longwave trough remain across the northeast
Saturday night and drifts offshore into the beginning of next as a
ridge builds to the west. Ridging will be weak, and another closed
upper low drifts toward the region Tuesday into Thursday. At the
surface, low pressure will be moving east of the region Saturday
night into Sunday with weak high pressure building in for Sunday
night into Monday. There is some uncertainty with the strength of
the high with the possibility that the high remains strong enough and
across the northeast to keep precipitation from the low approaching
from the southwest out of the area. A cool pattern continues through
the long term with temperatures near to below seasonal levels.
Followed the NBM guidance, which keeps slight chance probabilities
through much of the extended period.-- End Changed Discussion --
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
-- Changed Discussion --
High pres builds over the area tngt, followed by an approaching upr
lvl low for Fri.
VFR thru tngt. Shwrs and tstms develop Fri aftn with MVFR or lower
at times. A prob30 used for this activity due to uncertainty with
timing and coverage.
Generally W winds around 10 kt til around 00Z, then decreasing flow
with direction becoming vrb most arpts. Light winds on Fri with sea
breeze flow developing at the coasts.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Gusts decreasing in frequency this aftn and eve.
The JFK, LGA, and EWR haze forecast for today is MODERATE (YELLOW)
due to smoke.
Wind direction will be challenging on Fri, especially at LGA where
sea breeze flow may be NE off the Sound as opposed to S.
OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
Rest of Fri: MVFR or lower with shwrs and tstms.
Sat: VFR to start, then chcs for MVFR or lower in sct aftn shwrs and
tstms.
Sun: Mainly VFR. A slight chc for shwrs and isold tstms.
Mon-Tue: Slight chc of MVFR at times in shwrs. Otherwise VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
-- Changed Discussion --
Relatively weak pressure gradient in place through Saturday.
Sub-SCA conditions on forecast waters are expected outside of
any thunderstorms. Some thunderstorms Friday afternoon into
Friday evening may produce small hail and gusty winds,
potentially briefly getting to 35-40 kt.
A NW flow, less than 25 kt, behind low pressure Saturday night will
keep seas and waves below advisory levels. A weak pressure gradient
Sunday into midweek will keep winds and seas below advisory
levels.-- End Changed Discussion --
&&
.HYDROLOGY...
-- Changed Discussion --
Minor flooding will be possible, especially in low lying and
poor drainage areas, with repeated episodes of heavy rain
Friday afternoon through Friday evening. Total rainfall Friday
through Saturday is forecast to be near 1 inch. Locally higher
amounts will be possible.
No hydrologic impacts are expected Saturday night through mid
next week.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
-- Changed Discussion --
There is a moderate risk for the development of rip currents at the
ocean beaches this evening through Saturday evening.
Minor coastal flood benchmarks may be approached for the western
south shore back bays of Queens and Nassau Friday and Saturday
evening. At this time advisory level coastal flooding is not
anticipated.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JM/MET
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...MET
AVIATION...JMC
MARINE...JM/MET
HYDROLOGY...JM/MET
TIDES/COASTAL FLOODING...MET