000
FXUS61 KOKX 172048 CCA
AFDOKX
Area Forecast Discussion...CORRECTED
National Weather Service New York NY
448 PM EDT Wed May 17 2023
.SYNOPSIS...
Strong high pressure builds across the area tonight into
Thursday morning. The high pressure area will then move east of
the region Thursday afternoon through Thursday night. A frontal
wave along the southeast coast on Friday will work north along
the eastern seaboard ahead of an approaching cold front over the
Ohio Valley and Great Lakes states. Both will converge upon the
area Saturday into Saturday night. Following the cold frontal
passage early Sunday morning, high pressure will then build into
the area through early next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
-- Changed Discussion --
An anomalously cold airmass moves across the region tonight with
forecast model 850 mb temperatures near to slightly below
freezing along with the upper level jet positioned near to just
south of the region. The upper level jet streak maxima will be
shifting east of the region tonight into early Thursday morning.
NAEFS mean temperature plots at 850mb show the local area with
these temperatures being near 2 to 3 standard deviations below the
mean.
At the surface, strong high pressure builds into the region with
its center moving right across the forecast region. This will
allow for winds to decouple across the land, becoming very light
and the subsidence will allow for clear sky conditions. This
will be an ideal environment for radiational cooling. MOS has
trended slightly colder and a MAV/MET MOS combination was used
for lows. These new forecast temperatures show Western Passaic
NJ through Northern Rockland and Northern Westchester NY, as
well as Northern Fairfield and Northern New Haven CT to be
mostly near or below freezing. In addition, the new forecast
temperatures convey much of Northern and Southern New London as
well as the western half of the Eastern Suffolk NY zones to be
near or below freezing. Freeze warnings have been adjusted
with new issuances for the area aforementioned.
Forecast lows range from mid 20s to upper 20s in coldest spots,
in Pine Barrens of Long Island as well as parts of the interior
to the upper 40s for parts of NYC.-- End Changed Discussion --
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
-- Changed Discussion --
Mid and upper level ridging take place across the area Thursday
into Thursday night. A combination of MAV and MET MOS data was
used for high temperatures Thursday and low temperatures Thursday
night.
Sunny and dry conditions forecast to continue Thursday with high
pressure slowly moving east of the region. The pressure gradient
being weak will keep winds light but will increase along the
coast in the afternoon as synoptic flow becomes southerly along
with sea breezes. Forecast highs are in the upper 50s to lower 60s
for much of the area, with some mid 60s for parts of the interior,
farther away from marine air.
Mostly clear night and dry conditions Thursday night with high
pressure continuing to slowly move farther east of the area.
Light southerly flow remains so this will mitigate the
radiational cooling partially. Forecast lows will range from the
upper 30s in the Pine Barrens of Long Island to lower 50s within
much of NYC.-- End Changed Discussion --
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
High pressure continues to retreat offshore on Friday with a
strengthening S/SE flow ahead of a frontal system over the Great
Lakes. Temperatures will be right around normal on Friday.
An upper trough tracking across the Great Lakes Friday and into the
Northeast on Saturday will send a cold front toward the region. At
the same time, a frontal wave forming along a coastal front along
the southeast coast on Friday, will track north along the eastern
seaboard ahead of the digging upper trough. Model differences hinge
on how quickly the upper trough closes off. The GFS is the most
progressive and quickest of the global models, sending the front
through much of the area by midnight Saturday. The Canadian and
ECMWF are closer to a frontal passage around daybreak. This will
also impact the how far west the axis of heaviest rainfall gets with
the frontal wave preceding the cold front on Saturday. Right now,
staying fairly close to the NBM/WPC QPF, the heaviest rains look to
be across far eastern LI and SE CT on Saturday, dropping off quickly
to the west due to a sharp gradient. There will likely be some
west/east shift of this axis over the next couple of days. Rainfall
amounts currently range form a quarter inch far west suburbs, to
around an inch far east sections.
Following the cold frontal passage, the rain should come to an end
for most areas by daybreak Sunday, except for some lingering showers
in the morning. Once gain though, this will depend on any timing
changes with the upper trough/closed low. In addition, there is
marginal instability with warm, moist air being pulled up ahead of
the coastal low in a S/SE flow. Thus, have a low chance for some
embedded convection.
Thereafter, strong high pressure builds in from the west through
early next week with dry, nearly seasonable weather.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
High pressure builds in from the northwest through this evening.
VFR. N to NW winds 15 to 20 kt sustained with gusts up to around 25
kt. Winds and gusts diminish into this evening, then veer N to NE
for the overnight hours. Some outlying terminals may become light
and variable late tonight. NE winds Thursday morning shift southerly
with sea breezes late morning in to early afternoon 10-15 kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
End time of frequent wind gusts may be off by 1-2 hours.
OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
Thursday PM and Friday: VFR.
Saturday: Chance of MVFR or lower in rain/showers
Sunday: Chance MVFR/showers early, then VFR.
Monday: VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
-- Changed Discussion --
Gusty NW winds with 25 kt gusts expected on most of the forecast
waters until early this evening. SCA for all forecast waters goes
until 8PM EDT. Non-ocean waters expected to have below SCA
thresholds after 8PM tonight through the rest of tonight. The
ocean waters will remain in SCA through all of tonight, ending at
6AM EDT Thursday morning with some lingering 25 kt gusts and
higher seas across the ocean, especially for the first half of
tonight. Then, with high pressure building more across the
waters, the pressure gradient will weaken, allowing for winds and
seas to be well below SCA thresholds by early Thursday morning.
With high pressure in control and the pressure gradient remaining
relatively weak, conditions on Thursday and Thursday night are
expected to remain below SCA across all forecast waters.
Conditions will remain below SCA through Friday night. Waves on the
ocean water build in response to a strengthening S to SE flow ahead
of coastal low, with 4-7 ft seas possible by Saturday afternoon.
Waves diminish late Saturday night into Sunday afternoon. Conditions
fall below SCA Sunday night. High pressure builds in from the NW
early next week with sub-SCA conditions.-- End Changed Discussion --
&&
.FIRE WEATHER...
Continuing with the Red Flag Warning for CT zones into early
this evening with min RH values in the 20s, antecedent dry
conditions and a anomalous dry airmass in place for this time of
year. NW winds via strong mixing will result in NW winds
gusting 20 to 25 kt at times. Special Weather Statements are in
effect for NY and NJ zones after coordination with state fire
weather partners. Thus continuing with the elevated potential
for fire spread into early this evening.
&&
.HYDROLOGY...
There continues to be no hydrologic concerns at this time through
early next week.
&&
.CLIMATE...
The following are record temperatures for Thursday May 18th.
Currently the forecast reflects that records will be reached at some
of our climate sites with respect to the minimum temperatures.
Record Minimum Temperatures for Thursday May 18th
-------------------------------------------------
Central Park........41 (1973)
LaGuardia...........44 (2002,1973)
Kennedy.............42 (2003,1973)
Islip...............38 (2003,1973)
Newark..............43 (2003,1983,1955)
Bridgeport..........41 (1984,1983)
&&
.EQUIPMENT...
The OKX radar is operational.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Red Flag Warning until 8 PM EDT this evening for CTZ005>012.
Freeze Warning from 1 AM to 8 AM EDT Thursday for CTZ005-006-
008-012.
NY...Freeze Warning from 1 AM to 8 AM EDT Thursday for NYZ067>070-
079-081.
NJ...Freeze Warning from 1 AM to 8 AM EDT Thursday for NJZ002.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ331-
332-335-338-340-345.
Small Craft Advisory until 6 AM EDT Thursday for ANZ350-353-
355.
&&
$$
SYNOPSIS...JM/DW
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...DW
AVIATION...JC
MARINE...JM/DW
FIRE WEATHER...
HYDROLOGY...JM/DW
CLIMATE...
EQUIPMENT...