000
FXUS61 KOKX 281108
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
708 AM EDT Sun May 28 2023
.SYNOPSIS...
High pressure will be in control through the remainder of the
holiday weekend. A backdoor cold front moves through on Monday,
otherwise high pressure will dominate the upcoming week, with
weakening southern low pressure tracking south of the region.
A cold front then approaches Friday and passes though late
Friday. Canadian high pressure builds back into the region for
the weekend.
&&
.NEAR TERM /THROUGH MONDAY/...
A blocking upper high will remain from the Great Lakes into
the Northeast through Monday, while an upper low meanders over
the southeast states. A shortwave will pass across southeast
Canada and the Maritimes tonight helping to push a backdoor cold
front through the area on Monday. High pressure will otherwise
be in control of the weather.
The center of the high will be situated southeast of the area
today allowing southerly flow to continue through the day.
Coastal locations will see highs in the lower to middle 70s with
inland areas and points just NW of the city reaching the upper
70s to around 80 degrees. Temperatures tonight will be milder
than the last few nights with lows in the low 60s in the NYC
metro and 50s elsewhere. Mostly clear skies are expected through
tonight although there will be some cirrus clouds near the
coast from time to time. This high level moisture is from the
upper low over the southeast. However, the upper ridging and
subsidence will keep any of the thicker high clouds well to our
south.
The backdoor cold front moves through Monday afternoon. The
front will move through the region dry, but shift winds to the
E and then NE late. Temperatures should still be able to warm
into the 70s for most and lower 80s across the Lower Hudson
Valley and northeast NJ. The E flow increases in the afternoon
as the front moves through bringing a shot of cold advection.
Temperatures will begin to fall into the 60s in the mid to late
afternoon across Long Island and southern Connecticut and then
start reaching the rest of the area in the early evening. E-NE
winds 10-15 mph with gusts 20-25 mph are expected, strongest
near the coast late in the day.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
A reinforcing high pressure builds over New England Monday
night, remaining nearly stationary on Tuesday. The high weakens
a bit on Wednesday, but will still dominate the surface
pattern. Not much change is anticipated aloft with the blocking
upper high remaining in place over the northeast. The upper low
over the southeast may slowly lift towards the Middle Atlantic
coast into the midweek. However, the upper ridging will continue
to provide subsidence and keep any precipitation to our south.
Breezy conditions will continue Monday night, especially near
the coast. Lows will fall into the middle and upper 40s inland
and lower to middle 50s near the coast. Highs on Tuesday will
likely end up slightly below normal with continued E flow. Highs
will range from the upper 60s (coast) to middle 70s (well NW of
NYC metro). Cool conditions are expected again on Tuesday night
similar to those forecast on Monday night. Moderating
temperatures likely occur on Wednesday as the E flow is much
weaker and gradually becomes SE in the afternoon. Highs will
range from the lower to middle 70s south to upper 70s and low
80s north.
Some cirrus clouds are likely to move overhead as the aforementioned
upper low starts to reach the Middle Atlantic. These clouds should
not impact sky conditions much with mostly sunny skies both
Tuesday and Wednesday.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
Persistent ridging surface/aloft breaks down midweek, allowing
the filling southern US closed low to drift northeast towards
the area Wed/Thu. Models have trended a bit slower and farther
north with this low, eventually shearing it east and offshore
Friday ahead of a strengthening SE Canada upper low drifting
south. Troughing around the northern upper low will exert its
influence on the NE US heading into the weekend.
Surface high pressure continues to weaken Wednesday into
Wednesday Night, while the weakening southeastern low drifts NE
off the Mid Atlantic coast. Its precip shield will get close as
the low passes just to the south, with a low probability of
skirting southern portions of the area Wed NIght into Thu. There
has been a slower and farther northward trend with this low
over the last 48 hours, so will have to see if POPs trend upward
a bit for Wed Night/Thu. Accordingly, temps will be a bit
tricky Thu, based on evolution of the shearing low and amount of
associated high/mid clouds. Have stayed close to NBM
deterministic based on this uncertainty, although noted that
deterministic is running between the 10th and 25th percentile of
NBM ensemble spread. With WNW flow aloft advecting in a very
warm airmass (building across Ontario and Quebec midweek) ahead
of an approaching cold front, this still presents very warm
conditions across the area (upper 80s to around 90s for NYC/NJ
metro and point N&W to upper 70s/lower 80s for the coast) . The
weak flow, leading to progressive afternoon seabreeze
development, along with potential cloud cover, would limit
potential to reach the max temp potential of lower to mid 90s
across interior and well into the 80s for the coast signaled by
the NBM ensemble 50th percentile.
Greatest potential for hot and dry conditions appears to be
Friday with continued W/NW flow aloft advecting in 850hpa temps
of 16-17C, downslope flow, and deep mixing above 850mb. Timing
of cold front passage is one caveat, although medium range
guidance has trended slower with this, more towards evening. NBM
deterministic is currently running at or below the NBM ensemble
10th percentile, which is still lower 90s NYC/NJ metro and
interior and well into the 80s for the coast (about 15 degrees
above seasonable). Have blended NBM deterministic with NBM
ensemble 50th percentile based on ideal downslope heating setup,
which may still be too conservative based on NBM deterministic
performance in these events. Potential for forecast high temps
to trend into the lower to mid 90s across NYC/NJ metro and
interior, and upper 80s to lower 90s for much of the coast if
the downslope set-up become realized. Heat indices will likely
be at or below ambient temps due to the dry airmass.
The cold front passes through sometime Friday eve, although
timing is still uncertain. Moisture and forcing will be limited
in NW flow regime, which should limit shower/tstm activity to
isolated at best with passage.
Canadian maritime high pressure builds towards the area Friday
Night into Saturday with gradual caa and dry conditions, but
temps still likely running a few degrees above seasonable in the
upper 70s to lower 80s Saturday. Canadian maritime airmass may
become more entrenched Sunday, with continued dry conditions but
temps falling to near seasonable.
&&
.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
High pressure gradually weakens and moves offshore today into
tonight. A backdoor cold front approaches Monday late
morning/afternoon.
VFR conditions. Light S/SW flow for the morning push, gives way
to afternoon S/SSE 10-15kt seabreeze development this
afternoon. S winds diminish during the evening push, becoming
light and variable tonight.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Light S/SW flow, gives way to afternoon S/SE 10-15 kt
seabreeze. Timing of seabreeze could be off by an hour or so. A
few gusts to 20 kt possible for KJFK/KLGA in the late afternoon.
OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
Monday: VFR. Light NE winds for early AM push, then fropa with
E winds 15G20-25kt during the late morning. Fropa could be as
early as tail end of morning push.
Tuesday through Thursday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Cold water headlines continue through the holiday weekend for
cold water immersion threat from sub 60 degrees waters.
A relatively weak pressure gradient this weekend will keep
conditions below SCA levels through Sunday night.
Winds may approach 25 kt Monday afternoon and evening on the
ocean, LI Bays and eastern LI sound as a backdoor cold front
moves through. Ocean seas may also reach 5 ft late Monday
afternoon into Monday night. Have held off on an SCA issuance
for now based on collaboration with neighboring offices. The
gradient relaxes by Tuesday morning with sub SCA conditions
continue through the end of the week. Persistent SE swells
gradually subside middle to late week.
&&
.HYDROLOGY...
The prolonged stretch of dry weather continues through the
upcoming week.
&&
.TIDES/COASTAL FLOODING...
A moderate risk of rip current development at Atlantic Ocean
beaches continues today with 3ft@7-8 second SE swells today.
An increasing E flow Monday may bring seas close to 5 ft late
Monday afternoon. A moderate risk of rip current development
continues, but a high risk may be needed for Monday afternoon if
the seas build several hours faster than currently expected.
Rip current activity will likely be enhanced in vicinity of groins,
jetties, and piers through this period with E to W longshore
current.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DS/NV
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...NV
AVIATION...NV
MARINE...DS/NV
HYDROLOGY...DS/NV
TIDES/COASTAL FLOODING...