000
FXUS61 KOKX 192000
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
400 PM EDT Mon Jun 19 2023
.SYNOPSIS...
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Canadian maritime high pressure builds down from northern New
England and the Gulf of Maine through Wednesday, and then
slowly pushes east into the northern Atlantic as a frontal
system over the southeast US slowly moves north into the
weekend. This frontal system will continue to affect the
forecast area through the weekend, weakening as it does so.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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A broad upper trough remains across New England into tonight. A
weak shortwave within this flow approaches from the north late
today and shears through the region overnight.
This forcing, combined with inland trekking sea breeze boundary
may be focus for isolated shower activity across the far
interior into this evening. Minimal surface based instability
across the interior will mainly be relegated below the mixed
phase region under a mid-level cap, keeping the potential for
isolated thunderstorm activity quite limited.
Any shower activity will reduce in coverage this evening with
loss of diurnal instability, but with shortwave energy shearing
through, an isolated shower threat will remain across far
interior portions of the area into the overnight.
High-res guidance and soundings indicating stratus deck re-
developing to the south of the region and working into southern and
western coastal areas late this evening into the overnight. Fog is
not strongly indicated as airmass temps are similar or cooler than
water temps, but patchy fog/mist development is possible along
south coasts. Drier air across NE sections of the region, may
limit stratus development.
Temperatures will be near normal (upper 50s interior to lower 60s
coast).-- End Changed Discussion --
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
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Closed low continues to slide east of the Canadian Maritimes
thru Tue Night, with associated broad upper trough lingering
but weakening across New England. A stronger shortwave pivots
around the trough through coastal New England Tuesday morning
into early afternoon, with weakening trough axis sliding towards
the region overnight.
Morning stratus along the coast expected to gradually lift through
the morning with daytime heating, but may remain trapped beneath an
850-900mb subsidence inversion resulting in sct to bkn cloud
cover. A stronger easterly flow on Tuesday compared to today as
offshore Canadian maritime high noses westward will likely keep
much of the coastal plain under a relatively stable maritime
airmass. Despite the shortwave energy pivoting thru to the NE,
moisture convergence and weak instability development will
likely be relegated to the higher terrain north of the local
forecast area (Berkshires and Taconics) where iso to sct shower
activity is likely to develop. This activity could drift S/SSW
into far northern portions of the area based on mean steering
flow, but overall prob of shower activity looks to be low. Highs
a bit below normal with deep maritime flow, upper 70s interior
to lower to mid 70s coast.
Dry conditions Tuesday Night, with potential for a bit of
radiational cooling well down into the 50s across interior.
Along the coast, stratus development possible with continued
easterly flow, with temps likely staying near seasonable.-- End Changed Discussion --
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
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The long term will be characterized by a blocky pattern atypical of
mid-June for this part of the country. An omega block on Wednesday,
with a cut off low over the southeast US and another over the
Pacific Northwest, will transition to a blocked pattern where the
cutoff low over the southeast US slowly drifts north as a cutoff
high develops over southeast Canada and slowly drifts east. This
cutoff low and associated frontal system slowly weakens as it heads
toward the forecast area. Outside of Wednesday, much of the rest of
the week can be expected to be unsettled with this type of pattern
in place.
Wednesday, as previously mentioned, is expected to be dry with high
pressure centered to the north and east of the region. An easterly
flow will allow for low level moisture to increase, allowing for a
mostly cloudy day, and continued below normal temperatures, with
highs only in the lower to middle 70s, with the warmest conditions
expected north and west of New York City.
Thursday is expected to be even cooler thanks to a continued
easterly flow and the possibility of rain cooled air as the cutoff
low and its surface reflection along with the frontal boundaries
head north. It remains to be seen how much rain will actually move
into the region, as it will be fighting the dry air associated with
the offshore high. Northeastern areas may be warmer than
southwestern areas as these areas will be closer to the high, and
therefore, less in the way of rain and clouds are expected. Highs
will be in the lower to middle 70s. However, some models indicated
parts of the forecast area may not climb above the upper 60s to
around 70.
Later in the week, as the high continues to push east and the cutoff
low head into the mid-West, a southerly flow develops, allowing for
temperatures to warm to more seasonable, but slightly below normal
levels, for this time of year. The southerly flow will also allow
for an increase in humidity levels as dew points rise into the
middle to upper 60s from Friday through the beginning of next week.
The upper low weakens into a trough late Friday into Friday night
that remains to the west of the area into Saturday, and could be
around through the weekend.
The increase in humidity and the warmer temperatures will allow for
more in the way of instability, and thus thunderstorms to develop
during the afternoon and early evening hours from Friday onward.-- End Changed Discussion --
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
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Weak surface cold frontal boundary remains within the area with high
pressure building in the Gulf of Maine during the TAF period.
VFR conditions continue through this evening but low stratus will
develop and is expected to move in late tonight into Tuesday
morning, lowering conditions to MVFR and possibly down to IFR for
some terminals. The stratus is expected to scatter out later in the
TAF period during Tuesday afternoon.
Regarding weather, there is a slight chance for showers and
thunderstorms near KSWF as well as possible MVFR late this afternoon
into this evening with lesser chances of showers elsewhere. Only
have VCSH for KSWF with otherwise probabilities being too low to
include showers in TAF.
Winds will generally be E-SE during the TAF period near 5-10 kt.
This afternoon, winds will be generally SE near 10-12 kt, and then
become more easterly tonight into early Tuesday decreasing to near 5-
8 kts.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Winds may be a few kts higher than forecast for NYC terminals before
00Z. MVFR timing could be a few hours off from TAF. Categories may
fluctuate late tonight into Tuesday morning. Localized IFR will be
possible late tonight into Tuesday morning.
OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...
Tue afternoon - Tue Night: Mainly VFR. Chance of MVFR/IFR cigs
at night. Possible showers and MVFR for north and west of the
NYC/NJ terminals day into early evening.
Wed: Possible Wed AM low clouds MVFR to IFR. Otherwise, mainly VFR.
E wind gusts 15-20 kt day into evening.
Thu: Chance for showers. MVFR possible at times. E wind gusts 15-20
kt day into evening.
Fri: Chance for showers. Possible thunderstorms near and NW of NYC
terminals, mainly afternoon into evening. MVFR possible at times.
Sat: Showers become more likely. Possible thunderstorms, mainly
afternoon into evening. MVFR possible at times. S wind gusts 15-20
kt in the afternoon into evening.-- End Changed Discussion --
&&
.MARINE...
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With high pressure building to the north of the waters today into
Tuesday Night winds will remain below SCA levels across the forecast
waters, but potential for ocean seas to build to marginal SCA Tue
Night into Wed with persistent and long fetch modest easterly
flow.
The potential development of coastal jet over the western ocean
zones on Wednesday and Thursday may create some local gusts to
25 kt on both days. The persistent easterly flow will allow
waves to build to 5 ft on the ocean waters on Wednesday,
building to 4 to 6 ft Wednesday night. Waves then diminish
Thursday night, falling below 5 ft by late Thursday night into
early Friday morning.-- End Changed Discussion --
&&
.HYDROLOGY...
No hydrologic impacts are expected through the end of the week.
&&
.TIDES/COASTAL FLOODING...
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There is a moderate risk of rip/longshore currents on Tuesday
for all Atlantic facing beaches as easterly winds waves builds
to 3-4 ft, mixed with a couple of residual se swells.
The rip/longshore current risk will likely climb to borderline
moderate to high risk on Wednesday with around 5 ft@7 sec
period ESE wind swell building in.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JP/NV
NEAR TERM...NV
SHORT TERM...NV
LONG TERM...JP
AVIATION...JM
MARINE...JP/NV
HYDROLOGY...JP/NV
TIDES/COASTAL FLOODING...NV