000
FXUS61 KOKX 151756
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
156 PM EDT Thu Jun 15 2023
.SYNOPSIS...
Weak high pressure positions itself south of the area today and
tonight. A frontal system and associated low pressure approach
Friday, with the frontal system passing through Friday night.
Weak low pressure remains in the area Saturday into Sunday. High
pressure then briefly returns Sunday night into Monday. Another
low moves into the area Tuesday and remains into midweek.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Forecast remains on track overall this afternoon. Diurnal
heating with cold pool aloft has resulted in cumulus
development. The clouds are scattered to broken in coverage.
Forecast highs are still mainly in the upper 70s to lower 80s.
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 /FRIDAY THROUGH FRIDAY NIGHT/...
With the upper level low and mid level forcing approaching Friday
morning look for a good amount of cloud cover. There is some
uncertainty on precise timing of the arrival of the forcing
mechanisms to generate shower and potentially embedded t-storm
activity. Taking a model consensus approach yields likely showers
with a t-storm chance towards the afternoon and evening. At this
time it appears that much of the instability will be more elevated
than surface based, but this could change if more sunshine can get
through earlier in the day. Thus the current thinking is that
thunderstorm activity should primarily be sub severe. Have kept
out any enhanced wording at this time, but small hail and gusty
winds may be included with subsequent updates. The 500 mb
height minimum then positions itself over the area Fri night
into early Sat am. Although there will be the loss of diurnal
heating into Fri night, there will likely still be enough
forcing to drive high end chance to low end likely showers.
Temperatures should be below normal Friday with highs mainly in the
middle and upper 70s due mainly to more pronounced cloud cover. Lows
Friday night will be more of the same with lows primarily in the
middle and upper 50s across the interior and more rural locations,
and near 60 or in the lower 60s for the NYC metro and along coastal
communities.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Ensemble means (GEFS/EPS) continue to depict a blocky pattern and
mean troughing over the eastern CONUS with a series of cutoff lows
moving through New England. Ridging then tries to build in from the
central plains by the end of next week but falls short, with mean
troughing shifting slightly east, but still influencing the area.
Thus, continued near to below normal temperatures and unsettled
weather for the long term. The NBM was followed closely for this
update.
Saturday into Sunday looks to be the most active day(s) at this
point. A deep upper low advertised by the global models approaches
the local area with an attendant sfc low and cold front passing
through the area by Saturday afternoon. Precipitation chances
increase through the day on Saturday as the cold front and upper low
approach, with model soundings showing around ~500 J/kg of MUCAPE
and 20-30kts of bulk shear. So thunderstorms are likely for the area
Saturday afternoon as well, with timing and coverage coming into
better focus over the next few days as CAMs cover the timeframe. The
CSU Machine Learning Probabilities had a 5% severe probability for
parts of the area, but have backed off this on the most recent run.
NBM probabilities of (any) thunder are in the 40-50% range for
Saturday afternoon and have increased slightly, especially over the
Lower Hudson Valley and SW CT over the past few cycles.
The low and associated cold front move east of the area by early
Sunday, though the upper low is slow to move out. Thus, Sunday
looks to be cloudy and showery--at least for the first part of the
day. Drier air advects in behind the system by Sunday night, and
with weak ridging aloft, Monday looks to be dry and seasonable.
The Tuesday - Thursday period again looks unsettled, with an upper
low approaching from the mid south, along with a series of vort
maxes from New England. Precipitation chances again increase
Tuesday through late Wednesday.
&&
.AVIATION /18Z 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 this afternoon may be more occasional than frequent.
The JFK, LGA, and EWR afternoon 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...
The winds will be mainly out of the west today with with ocean seas
3 to 4 ft today, and closer to 3 ft tonight. Ahead of the next
approaching frontal system on Friday look for more of a southerly
flow with ocean seas remaining around 3 ft. The winds will then
shift to the west later Fri night with sub small craft conditions
from Saturday through Monday with weak low pressure in the
vicinity Saturday and Sunday, and weak high pressure building in
for Monday.
&&
.HYDROLOGY...
No hydrologic impacts are expected through mid next week.
&&
.TIDES/COASTAL FLOODING...
There is a moderate risk of rip currents today and Friday.
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.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JE/DBR
NEAR TERM...JE/JM
SHORT TERM...JE
LONG TERM...DBR
AVIATION...JMC
MARINE...JE/DBR
HYDROLOGY...JE/DBR
TIDES/COASTAL FLOODING...