000
FXUS61 KOKX 222003
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
303 PM EST Fri Dec 22 2023
.SYNOPSIS...
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High pressure over the are will move east late tonight into
Saturday. A weakening warm front approaching Saturday night
will lift north on Sunday. High pressure will then reestablish
itself late Sunday into Christmas Day before moving offshore on
Tuesday. A frontal system will likely affect the area from
Tuesday night into the middle of next week.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH TONIGHT/...
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Bands of high/mid level clouds over the area attm will continue
to spread eastward into this evening. Another band of lower
clouds over S NJ into SE PA should also expand NE, and per
latest RAP/HRRR fcst soundings could make it into the NYC metro
area as early as late this evening but more likely after
midnight with partly to mostly cloudy skies.
With areas to the NE of there experiencing a mostly clear to
partly cloudy night with light winds, temps across interior S
CT and eastern Long Island should fall to the upper teens and
lower 20s. West of there lows should range from near 30 in NYC
to the mid 20s in the outlying suburbs.-- End Changed Discussion --
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
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The sfc high will move off the New England coast, with mid level
shortwave energy approaching as a mid level ridge axis also
slides east. That will allow for a continued gradually increase
in clouds daytime Sat, with daytime highs a few degrees warmer
than those of today, with mid/upper 30s inland and lower 40s for
NYC metro and the coast.
Combo of a mid level shortwave trough approaching from the west
Sat night and low level WAA on the back side of the high off
the New England coast will bring overcast skies and the chance
for some light precip from late Sat night into Sunday. With
combo of warming aloft and sfc temps falling to the upper
20s/lower 30s well inland (and models also showing some in-situ
cold air damming with sfc winds backing to the NE), a period of
light snow/sleet/freezing rain is looking more likely for areas
well NW of NYC (mostly Orange/W Passaic/Putnam/N Fairfield)
late Sat night into Sunday morning. Rain expected elsewhere with
lows from the mid 30s to near 40. With this being a late 3rd
period/early 4th period event, and the possibility that precip
could be spotty and temps remain just above freezing Sat night
especially outside of Orange County, it is still too
early/uncertain for any winter wx headlines.
Light rain/showers should continue spreading eastward across the
rest of the CWA into Sat morning, and then shift more to the
east across ern Long Island and SE CT by afternoon, with skies
remaining cloudy. As low level WAA continues, temps should reach
the lower 40s inland and mid 40s for the metro/coastal sections
by afternoon.-- End Changed Discussion --
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
The forecast in the extended has not changed too much over the
last 24 hours.
Key Points:
* Dry conditions expected for Christmas Day.
* Above normal temps early to mid week.
* A progressive rain event likely Tuesday night into Wednesday,
but there remains significant model spread on rain and wind
details. At this point the probability of this being a high
impact event is very low.
Complex upper air pattern across CONUS over the next several
days as a train of northern stream shortwaves moving through
southern Canada interact with a closed upper low coming into the
western US today. The general outcome of these interactions is
development of a deep central US trough early next week sliding
into the eastern US by mid- week. There is quite a bit of model
spread on the details of this trough, particularly intensity and
location of the closed low or lows over the Great lakes area,
anchoring this trough.
At the surface, general agreement on a primary area of low
pressure developing over the Central US and tracking into the
Great lakes early to mid week, with its associated frontal
system approaching the area late Tuesday and working through Wed
into Wed Night. Quite a bit of model spread on intensity of
primary low and potential development of secondary intensifying
low along the coastal plain (tied to the eventual closed low
evolution), which manifests in varying solutions of rain and
wind details.
NBM probabilities for greater than 1 inch of rain in a 12 hour
period remain at or below 10 percent. With that said, model
solutions with quicker secondary development along the coastal
plain (00z GFS) do indicate potential for over 1" of rain in 12
hrs with deep lift of a gulf/subtropical moisture feed (+2 STD
PWATS). Solutions with later and/or weaker secondary development
(00Z ECMWF) indicate a lighter event. With recent back to back
rainfall events, streamflows and soil moisture will likely
continue to run above normal during this time, so will bear
watching. NBM probs of 40-kt gusts (wind advisory) are below
5%, with even stronger 00Z GFS solution depicting only a
marginal signal for strong winds.
Models differences increase further with the evolution of the
upper trough for late week into weekend. This could continue
an unsettled pattern with a gradual cooling trend.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
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High pressure remains in control through Saturday. A warm front
will approach from the west Saturday night.
VFR. Generally light and variable winds through tonight. Light
S-SE winds developing late Sat AM, speeds at or under 5 kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Most likely direction would be E-NE less than 5 kt for PM push.
No unscheduled amendments expected.
OUTLOOK FOR 18Z SATURDAY THROUGH TUESDAY...
Saturday afternoon: VFR.
Sunday: MVFR possible, with isolated showers. Low prob for -FZRA
for KSWF late Sat Night/Sun AM.
Christmas Day: VFR.
Tuesday: Becoming MVFR or lower late, increasing likelihood for
rain.
Wednesday: MVFR or lower with rain.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
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Sub-SCA cond prevail with winds less than 10 kt, and ocean seas
3-4 ft attm, lowering to 2-3 ft late tonight, and around 2 ft
Sat afternoon through Sunday.
Sub-SCA conds then continue through Tue as high pressure slowly
slides east through the waters. Next chance for SCA cond for
the ocean and possibly all waters will comes Tue night into mid
week with a frontal system.-- End Changed Discussion --
&&
.HYDROLOGY...
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River flood warnings are still in effect along the CT and
Pawcatuck Rivers (handled by WFO BOX) and parts of the Passaic
River basin (handled by WFO PHI). Otherwise, no hydrologic
impacts are expected through Tuesday.
Rain is likely from Tue night into Wed night. Low predictability
continues on rainfall amounts and therefore hydrologic impacts.
Stream flows and soil moisture will likely continue to run above
normal during this time.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BG/NV
NEAR TERM...BG
SHORT TERM...BG
LONG TERM...NV
AVIATION...DR
MARINE...JE/BG/NV
HYDROLOGY...JE/NV