000
FXUS61 KOKX 242104
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
404 PM EST Sun Dec 24 2023

.SYNOPSIS...
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A weak surface trough will linger near eastern Long Island
tonight into early Christmas Day, then weaken as high pressure
to the east becomes reestablished. The high will then slowly
weaken on Tuesday. Low pressure approaching Tuesday night
through Wednesday will move near the area Wednesday night, then
pass to the northeast on Thursday. Another low will approach on
Friday, pass southeast of Long Island Friday night into
Saturday, then move farther out into the Atlantic on Sunday.
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&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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Cloudy skies continue with moisture trapped beneath a mid level
inversion, also with low clouds mostly across Long Island/S CT
with low level moisture trapped beneath a marine inversion.
Some spotty light showers associated with a weak sfc trough and
mid level forcing from an upper trough just to the NW across
upstate NY continue across the forks of Long Island and SE CT.
Forecast carries chance PoP in these areas as this weak forcing
continues, as the upper trough cuts off aloft beneath a building
longwave ridge and moves toward S New England.

Temps will cool off to near 40 in NYC, and into the 30s
elsewhere, remaining above freezing throughout.
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&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
Weak cutoff upper low will slowly sink SE across Long Island and
CT on Christmas Day, with continued chance for AM showers out
east. Otherwise, mostly cloudy skies should continue through the
period as the combo of moisture trapped beneath mid level and
marine inversions remains stubborn. With not much change in air
mass temps through Mon night should be similar to or only a
touch milder than those of today. Highs will be in the lower
50s for the NYC metro area and Long Island, and mid/upper 40s
inland and for the CT coast, with lows ranging from the lower
40s in NYC to the mid 30s well inland. Fog should also develop
over most of the area late Mon night into Tue AM as low levels
moisten up on a light onshore flow.

Model guidance has trended slower with the mid week system, so
have cut back PoP daytime Tue to slight chance west of the
Hudson for the late afternoon. WAA ahead of this system should
lead to a touch milder temps, with highs mostly in the lower
50s throughout.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...

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* Mid week rain event, around a half to 1 inch expected.
  Locally higher amounts possible. No more than localized minor
  flooding is expected.

* Forecast has above normal temperatures midweek transition to near
  normal temperatures going into next weekend.

Troughing synoptic pattern mid to late week will have a
corresponding surface pattern depicting a developing and
approaching low from the Southeast US Tuesday night into
Wednesday. Despite an increasing subtropical upper level jet,
the mid and upper level pattern remains positively tilted,
allowing for this system to remain pretty progressive. This will
limit the total rainfall.

The large scale numerical models do not depict too much
deepening with this low pressure system as it approaches and
eventually moves near the area Wednesday night.

Then, the low moves north to northeast of the area Thursday.
Another low develops and moves near the area Friday but is
shown to pass southeast of Long Island Friday night.

It appears the troughing pattern aloft lingers into next weekend
looking at the large scale numerical weather prediction models.
This will also point to a transition to a relatively colder
airmass for Friday and into the start of next weekend.

The pattern for Thursday through Friday night of next week
depicts the more unsettled pattern where there will be
periodic chances for rain and/or snow showers depending on the
timing of when the mid level vorticity maxima move in.
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&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
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High pres remains over the area thru Christmas Day.

Low clouds will linger thru the TAF period. MVFR to IFR cigs
expected at times, especially tngt and Mon mrng. Vis may drop
at times in BR tngt, but confidence is low so the TAF`s only
indicate 5SM.

Winds lgt and vrb thru the TAF period.

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

MVFR may not redevelop until aft 00Z. Periods of IFR possible
thru 16Z Mon. Timing and coverage too uncertain so not included
in the TAFs attm, although the best chances are 00Z-14Z.
Variability in wind direction possible at LGA where a general
light NE flow is fcst.

OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...

Christmas Day: Becoming VFR. Chance of MVFR or lower again aft
00Z Tue.

Tue: MVFR or lower at times.

Wed-Thu: MVFR or lower with rain.

Fri: Mainly MVFR. NE winds G20-30kt possible.

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

.MARINE...
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Conditions are forecast to remain below SCA thresholds through
Wed night with a relatively weak pressure gradient in place.
Chances then increase for SCA conditions on the ocean for
Thursday into Thursday night, mainly for seas. All waters
potentially could see 25-kt wind gusts Friday into Friday night,
with 5+ ft seas remaining on the ocean, as stronger westerly
flow develops.
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&&

.HYDROLOGY...
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Minor flooding along the CT River (warning handled by WFO BOX)
should subside late tonight.

QPF with the mid week system ranges from 1/2 to 3/4 inch.
Impacts appear limited to localized minor/nuisance poor drainage
flooding in areas of relatively heavier rainfall.
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&&

.TIDES/COASTAL FLOODING...
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Monitoring potential for minor coastal flood impacts for
vulnerable coastal communities Wed/Thu with a passing frontal
system. Tidal departures of 1.25-1.50 ft are needed for minor
flooding, and 2.25-2.50 for moderate flooding during the
morning high tides. About 1 ft additional surge is needed for
the evening high tides.

Blend of bias-corrected surge guidance keeps water levels below
minor thresholds, while a reasonable worst case blend of bias-
corrected Stevens Tech NYHOPS central and 95th percentile
forecasts indicates potential for minor flooding with the Wed
morning high tide cycle along the south shore of Nassau and for
Jamaica Bays, with water levels nearing minor benchmarks along
the SW CT coastline on the western Sound.
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&&

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

&&

$$

SYNOPSIS...BG/JM
NEAR TERM...BG
SHORT TERM...BG
LONG TERM...JM
AVIATION...JMC
MARINE...BG/JM
HYDROLOGY...BG/JM
TIDES/COASTAL FLOODING...