discussion on 2023-05-10

000
FXUS61 KOKX 102352
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
752 PM EDT Wed May 10 2023

.SYNOPSIS...
High pressure builds in from the Great Lakes through tonight.
High pressure moves east of the area Thursday and Friday with a
weak cold front approaching Thursday. A weakening cold front
moves through the region Saturday. High pressure then builds in
from the northwest through Sunday. The high weakens Monday as a
cold front approaches from the northwest. A pre frontal trough
develops Tuesday with the front moving through Tuesday night.
The high builds behind the front Wednesday.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Dew points remain higher, in the mid to upper 40s, along the
south shore of Long Island and the Connecticut coast as sea
breezes continue. Updated for current conditions and into early
evening when sea breezes will end, updated winds also, and dew
points fall off. Otherwise no other changes were needed.

A brief, weak surface trough is leading to some stronger winds
offshore, with winds sustained at 10-15 mph across several sites
on Long Island and southern Connecticut, some of which is also
associated with a sea breeze that is currently pushing through.
Have gone with the HRRR for the sea breeze circulation,
transitioning into using the NBM for wind values in the late
evening and overnight.

Winds are expected to gradually decrease as we go into the
evening as the surface trough weakens and high pressure
continues to remain in play. Clear skies are expected overnight
with light winds. This should allow for more radiational
cooling. However, warm air advection is also expected to take
place overnight being transported in from the west. This will
keep temperatures on the warmer side for most, in comparison
with last night`s temperatures. Used a blended solution between
the NBM and blended MOS which seemed to account for both warmer
temperatures, but also a proper amount of radiational cooling in
spots.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Amplifying ridge anchored over the eastern two thirds of CONUS
dominates the period resulting in mainly dry and warm conditions
for the area. Two distinct shortwaves, however, will traverse
the eastern side of the ridge into New England on Thursday
afternoon and then again late on Friday.

At the surface, high pressure heads to the east into the
western Atlantic on Thursday as a weak surface trough,
associated with the aforementioned mid/upper shortwave, pushes
east. This feature will provide the lift, and upper support, for
the development of isolated showers, and possibly a
thunderstorm, mainly across eastern CT. Model soundings from the
NAM/HRRR/HREF and others do depict an inverted-V signature with
a bit of MUCAPE into the afternoon. Given the sfc high to the
south and general lack of moisture, do not expect these
showers/thunderstorms to be very widespread and concentrated
mainly over northeast sections of the CWA. Given the increase in
coverage from the CAMs, including some that show activity as
far west and southwestern CT, have introduced slight chance PoPs
with isolated thunder across extreme eastern CT. Confidence is
low in coverage.

Nonetheless, expecting a mostly sunny day overall, with an
increasing Cu field by the afternoon and sea breezes across Long
Island. Temperatures will be a few degrees warmer than on
Wednesday, with 850 temperatures several degrees warmer, 9-12C,
yielding mid 80s across the interior and mid/upper 70s at the
coast. Went with the NBM for MaxTs which shows a spread of only
a few degrees between the 25th and 50th percentile, adding
confidence to the forecast.

The ridge aloft amplifies on Friday as 850mb temperatures again
increase a few degrees relative to Thursday, resulting high
temperatures in mid and upper 80s across the interior and upper
70s elsewhere. MOS databases even showing some near 90 degree
readings across northeast NJ. Have undercut that by a few
degrees, again given the relatively narrow spread in the NBM
MaxTs for upper 80s across the urban corridor, and with
dewpoints in the 50s, apparent Ts will be close to temperatures.

Dry conditions are expected for much of the day, as a weakening
cold front approaches from the north late, bringing a chance of
showers into early Saturday. Onset of this activity has been
slowed for this update per recent guidance more toward the early
Saturday timeframe. Have also maintained the patchy fog in the
forecast for overnight Friday, given light winds and increasing
boundary layer moisture.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The long term forecast generally similar to previous forecasts
with minor timing and spatial coverage changes with the passage
of one weak cold front during Saturday, and another prefrontal
trough and cold frontal passage Tuesday into Tuesday night. The
front for Saturday remains weak with little forcing and
moisture. Also, the frontal wave approaching from the west
Saturday is a little slower and will be farther to the south.
Generally used the NBM probabilities with some adjustments, as
the chances for rain will be later and higher to the west and
south. Any rainfall will be light. Also, with the timing of the
cold front Saturday leaned toward the lower 25th percentile
temperatures. There is some uncertainty with the track of
another weak low Sunday night into Monday with the track a
little farther to the south. Guidance has been trending drier
and will have only slight chance probabilities A similar
situation will occur with the next cold front approaching from
the northwest Monday and passing through Tuesday/Tuesday night.
The passage has now trended dry. Followed NBM temperatures
Sunday through Wednesday with temperatures near to slightly
above seasonal normals.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --High pressure remains in control with VFR conditions through TAF
period.

S to SW winds become more westerly after 03Z as the sea breeze
diminishes. On Thursday WNW winds up to 10 kt, with a period of
gusts possible from the 18z to 22z timeframe for a few of the city
and coastal terminals. A sea breeze develops again on Thursday, but
is likely only for KJFK, KISP, KBDR and KGON.

An isolated shower/thunderstorm is possible near KGON in the late
afternoon. Confidence in occurrence and coverage is too low to
include in the TAF at this time.

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

Timing of sea breeze may be off for KJFK by 1-3 hrs on Thursday.


 ...OUTLOOK FOR 0Z FRIDAY THROUGH MONDAY...

Thursday night...VFR.

Friday...VFR.

Saturday...Possible MVFR in a chance of showers.

Sunday...VFR.

Monday...Possible MVFR in slight chance of showers.

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

&&

.MARINE...
No changes to winds and seas at this time.

Expect below SCA conditions on all waters this afternoon and
evening though an occasional 25kt gust east of Sandy Hook cannot
be ruled out. Otherwise, expecting below SCA conditions through
early Saturday.

Winds and seas remain below SCA levels across the forecast waters
Saturday through Monday night as a cold front passes through
Saturday, otherwise generally high pressure will dominate.

&&

.HYDROLOGY...
No hydrologic impacts are expected through Wednesday of next
week.

&&

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

&&

$$
SYNOPSIS...DBR/BR/MET
NEAR TERM...BR/MET
SHORT TERM...DBR
LONG TERM...MET
AVIATION...JE
MARINE...DBR/BR/MET
HYDROLOGY...DBR/BR/MET