discussion on 2023-05-26

000
FXUS61 KOKX 262148
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
548 PM EDT Fri May 26 2023

.SYNOPSIS...
-- Changed Discussion --High pressure will continue building in from the Great Lakes
before beginning to weaken and shift offshore towards the
latter half of the holiday weekend. A backdoor cold front likely
moves through during Monday afternoon into evening. High
pressure otherwise remains in control through Thursday with
another cold front passing through during Friday.-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
-- Changed Discussion --The forecast is mostly on track with minor updates made mainly
to temperatures, dewpoints and cloud cover for the next few
hours.

Subsidence occurs heading into early evening with a thermal
trough dissipating as temperatures cool and pressure tendency
increases. Surface high pressure will build in tonight with
ridging aloft. As a result, winds decouple, become lighter,
and sky conditions will remain mostly clear. This will provide
ideal radiational cooling conditions. For the forecast lows
tonight, used a blend of 3/4 of the relatively cooler MAV MOS
and 1/4 of the relatively warmer MET MOS with a more vast range
of temperatures from the upper 30s in the Pine Barrens of Long
Island to upper 50s within parts of NYC.-- End Changed Discussion --

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/...
Aloft in the mid levels, continued ridging takes place along
with negative vorticity advection Saturday into Saturday night.
The ridging begins to break down in the mid levels Saturday
night into Sunday. High pressure at the surface overall will
still be in control with dry conditions continuing.

For Saturday, high pressure will continue to remain in control
with its center moving across the region. The weakness in the
pressure gradient will keep winds light and allow for sea breeze
circulations to easily develop during the afternoon. More
southerly flow is expected during the afternoon but winds remain
relatively light, around 10 mph or less on average. Winds will
be relatively higher along the coast compared to farther inland.
Subsidence from the high pressure will still be evident with
mostly sunny conditions.

The vertical mixing will be less than that of the previous day. With
model 850mb temperatures trending a few degrees higher compared
to the previous day, surface temperatures will likewise be
trending warmer compared to the previous day as well. The
limited vertical mixing and sea breeze will counter some of the
warming trend but still the net result will be warmer
temperatures compared to those of Friday. The forecast highs
are are a blend of NBM as well as MAV and MET MOS, ranging from
near 70s for eastern coastal locations, to the upper 70s across
much of the interior including Northeast NJ and much of NYC.

For Saturday night, high pressure remains strong but becomes
positioned more offshore, allowing for a prevalence of very light
southerly flow. Also, the high pressure area loses a little
strength going into early Sunday morning. The subsidence from
the high will keep clouds a low coverage and with the winds
being light, radiational cooling will be nearly optimized once
again. Forecast lows were a blend of MAV and MET MOS guidance,
ranging from the lower 40s in the Pine Barrens of Long Island to
near 60 for parts of NYC.

For Sunday, high pressure will continue to weaken and will remain
based offshore. The will allow for a slightly stronger
southerly flow to develop with the enhancement from the sea
breeze circulation development. Coastal locations will have more
in the way of gusts, getting up to around 20 mph, develop
during the afternoon. With less subsidence, also expecting
clouds to have a greater presence during Sunday, especially by
mid to late afternoon. As a whole on average though, another
mostly sunny day is expected. Model 850mb temperatures continue
to warm up a few degrees compared to Saturday. This warming
trend will be mitigated at the surface due to the sea breeze and
some extra clouds along the coast so high temperatures here
will not be too different from those of Saturday. However, for
inland as well as Northeast NJ and NYC more of a warming trend
is forecast, with forecast highs in the mid 70s to upper 70s
with some locations reaching near 80.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
The long term period will be dominated by an anticyclonic flow aloft
and high pressure at the surface, but a couple of cold fronts are
expected to pass through. The first of which is anticipated on
Monday afternoon as a backdoor cold front drops down from the north.
This will bring somewhat breezy conditions with a shot of cold air
advection. Inland high temperatures should still be able to sneak
into the 80s before the onset of cold advection, but coastal areas
are likely held in the 70s as the easterly wind flow ushers in cool
air from the ocean and LI Sound waters. Additionally, the front will
be passing through with little moisture, so dry weather is
anticipated.

Remaining dry for at least Tuesday through Thursday with highs on
Tuesday at or slightly below normal. Highs then moderate Wednesday
and Thursday, with Thursday`s highs possibly reaching 90 for some
inland spots. Dewpoints on Thursday will be only in the 50s, so heat
indices will be at or below ambient temperatures.

The next cold front passes through sometime on Friday, although the
part of the day in which the front passes through is uncertain.
Based on NBM PoPs and QPF fields from the global models, will leave
in a slight chance of showers Friday afternoon into Friday evening.
Highs primarily in the 80s across the area with some 90s inland. No
heat advisory concerns due to dewpoints in the 50s again.

&&

.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
VFR as high pressure remains in control through the weekend.

Northerly flow and deep mixing will likely delay the seabreeze
to late afternoon/early evening for the coastal terminals.
Elsewhere, N winds will generally be at 10 kt or less with
occasional gusts 15-18kt early. Winds will then go light and
variable tonight, becoming light NE after 12Z Saturday, then SE
by afternoon at 10 kt or less.

     ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

Timing of seabreeze could be delayed by 1-2 hours.

OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY...

Saturday-Wednesday: VFR. E winds G15-20kt Monday and Tuesday.

Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90

&&

.MARINE...
With the pressure gradient remaining relatively weak overall,
conditions on all forecast marine zones are expected to remain
below SCA thresholds through much of the holiday weekend.

A cold front passes through the waters Monday afternoon. With a shot
of cold air advection and a tightening pressure gradient, gusts to
25 kt will be possible on most waters during the afternoon and
evening. Additionally, an easterly wind may build seas up to 5 ft on
the ocean during Monday night. After possible lingering SCA conds on
the ocean Tuesday morning, sub-advisory conds continue thereafter
through Wednesday as an onshore wind weakens to below 15 kt.

&&

.HYDROLOGY...
The prolonged stretch of dry weather continues through the entire
forecast period.

&&

.TIDES/COASTAL FLOODING...
-- Changed Discussion --A moderate risk of rip current development on the ocean waters
is expected to continue Saturday through Monday.-- End Changed Discussion --

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$
SYNOPSIS...JC/JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...JC
AVIATION...DW
MARINE...JC/JM
HYDROLOGY...JC/JM
TIDES/COASTAL FLOODING...