636
FXUS61 KOKX 140834
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
334 AM EST Sat Dec 14 2024
.SYNOPSIS...
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Strong high pressure remains in control through Sunday. A
weakening disturbance will move across the area Sunday night
into Monday. A frontal system will then move through the area
Monday night into Tuesday, followed by high pressure Tuesday
night into Wednesday. A cold front or complex coastal low
pressure system may affect the region Wednesday Night into
Friday.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH TONIGHT/...
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The main story for today continues to be strong high pressure
over the northeast and cold temperatures. The upper trough that
was with us to end the week will continue to move off the new
England coast leaving behind strong confluence over the
northeast. This will allow the high to strengthen to 1047-1049
mb with its center just north across northern New England and
upstate NY. See climate section below for details on high
pressure records for December and all-time across the northeast.
There will be a light northerly flow that will maintain very
dry air and dew points in the single digits to around 10
degrees. Temperatures should be able to rise a degree or two
above those observed on Friday, but still around 10 degrees
below normal for this time of year. Highs will only be in the
lower to middle 30s under sunny skies.
Shortwave ridging builds overhead tonight allowing the strong
surface high to remain in place over the region. The confluence
pushes east and weakens, so the central pressures in the high
should begin to fall into early Sunday morning. Overall there
will be very little change to sensible weather for tonight.
Ideal radiational cooling conditions with nearly calm winds, dry
air, and clear skies will allow temperatures to bottom out in
the teens inland and Long Island Pine Barrens with lower to
middle 20s elsewhere. There may be a slight increase in high
clouds towards day break Monday as the ridge axis starts to move
through, but these should have little impact on temperatures.-- End Changed Discussion --
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
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The ridging will continue sliding east of the area on Sunday.
This will allow the surface to gradually weaken as it begins
moving off the New England coast by Sunday evening. A compact
middle level shortwave will rapidly approach on its heels Sunday
night and move across the area Monday as it weakens. A stronger
shortwave and associated frontal system begin impacting the
area Monday night
Dry conditions will continue on Sunday during the day, but clouds
will gradually lower and thicken from west to east through the day.
Temperatures will moderate several degrees compared to Saturday, but
still remain below normal in the mid to upper 30s inland and near 40
along the coast.
Attention then turns to the aforementioned first
shortwave/disturbance that rapidly approaches Sunday night.
There has not been too much change with the overall forecast
evolution with this system with the main concerns continuing to be
with precipitation types north and west of the NYC metro overnight
into early Monday. There is uncertainty with how much
temperatures fall Sunday evening due to thickening cloud cover
and warm advection ahead of the shortwave. The forcing should
be strong enough to saturate the dry low levels and allow precip
to begin as some light snow at the onset across the interior of
the Lower Hudson Valley and potentially NE NJ. The precip type
forecast becomes more tricky towards day break Monday as thermal
profiles begin to warm aloft around the same time as saturation
aloft begins to lower in height which could limit snow growth.
This will introduce potential for some light freezing rain
across the Lower Hudson Valley. Thermal profiles and surface
temperatures warm for the remainder of the NYC metro, Long
Island, and coastal CT to be just a cold light rain. Interior CT
is also tricky as precip may hold off till close to day break
and could struggle to work its way east as it encounters the
lingering ridging to the east. If precip can sustain itself
across interior S CT, it could begin as some light snow and
potentially mix with some light freezing rain as thermal
profiles quickly warm. Some sleet cannot be ruled out during the
transition period, but surface cold air looks shallow and the
continued boundary layer warm would more likely change precip to
liquid fairly quickly. Precip types for this forecast were
derived from a blend of partial thicknesses from the NAM, GFS,
and ECMWF with some local adjustments in areas that can stay
colder a bit longer than modeled.
Snowfall accumulation looks light across interior Lower
Hudson Valley and interior NE NJ and generally under an inch. A
light glaze of ice is also possible across these areas. Another
factor that will have to be watched is ground temps start out
cold given the recent stretch of temperatures. Some areas across
the interior may briefly rise above freezing the next few days.
This could create slippery travel initially during the morning
commute even if the precip is light. Will continue to highlight
this potential in the HWO. A winter weather advisory may
eventually be needed as confidence in precip types increases.
Any wintry precip inland should become plain rain by mid to
late morning. There are signals on the latest GFS, CMC, RGEM,
and ECMWF that precip will diminish in coverage by late Monday
morning and become spotty in the afternoon as the wave weakens.
Have followed this trend and brought PoPs down to chance in the
afternoon. Some spotty light rain is possible at times in the
evening with some patchy fog as there will continue to be weak
warm advection. Highs on Monday during the day range from low
40s inland to the mid and upper 40s elsewhere.
A more well defined frontal system will approach Monday night
with its associated warm front lifting north of the area into
early Tuesday morning. Temperatures should rise through the
night with many areas in the low 50s by day break Tuesday. Rain
becomes probable overnight from west to east as lift from the
associated shortwave quickly moves across the area.-- End Changed Discussion --
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
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No significant changes made to the long term Tuesday through the
end of the next week. There remains potential for a late week
strong front or coastal storm.
Rain continues Tuesday morning as a shortwave and associated
frontal system bring a quick shot of rain to the region.
Continued waa ahead of this feature will support an all rain
event with the rain tapering off from west to east late
morning/early afternoon.
High pressure briefly builds in for Tue Night into Wed with above
normal temps, before potential for a complex coastal system for the
late week period.
Considerable inherent model spread on evolution of the anomalously
deep trough continues for late week, manifesting in low pressure
track and timing differences, but potential exists for a heavy
precip event.-- End Changed Discussion --
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
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Strong high pressure will persist through the weekend with
VFR conditions.
NW-N winds less than 10 kt through the TAF period.
...NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
No unscheduled amendments are expected.
OUTLOOK FOR 06Z SATURDAY THROUGH WEDNESDAY...
Saturday Night: VFR.
Sunday: Chance of MVFR cigs at the NYC metro/coastal terminals
in the afternoon, spreading inland during the evening.
Sunday Night: Wintry mix at KSWF and rain elsewhere with MVFR-
IFR, mainly after midnight.
Monday: Wintry mix possible at KSWF early, otherwise light rain
likely early with MVFR or lower conditions expected.
Monday Night-Tuesday: Rain becoming likely with IFR or lower
conditions possible. The rain should end by Tuesday afternoon
with conditions returning to VFR. S-SW gusts 15-20 kt late
Monday night into Tuesday morning.
Wednesday: Mainly VFR.
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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Conditions will remain below SCA levels through Sunday with a
weak pressure gradient in place. The pressure gradient
increases a bit Sunday night into Monday as high pressures moves
off the New England coast, but winds and seas are expected to
remain below SCA levels. SCA conditions look likely Monday night
as seas build and winds increase to around 25 kt ahead of a
frontal system.-- End Changed Discussion --
&&
.HYDROLOGY...
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No hydrologic impacts are currently anticipated through the
end of next week.-- End Changed Discussion --
&&
.CLIMATE...
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Very strong high pressure has settled over the northeast will
remain in place into Sunday. The peak sea level pressure (SLP)
will remain just below the highest observed across the
Northeast not only in December but in any calendar month based
on data from WPC. The highest observed SLP in the Northeast
ranges from 1052-1054 mb, which occurred on February 13, 1981.
The highest observed SLP at Central Park was 1052.5 mb, which
also occurred on February 13, 1981. The highest observed SLP in
the Northeast for December ranges from around 1049-1053 mb
(1051.8 mb at Central Park), which occurred on December 25,
1949.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...JP/DS
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...NV/JP
AVIATION...JP/DS
MARINE...JP/DS
HYDROLOGY...JP/DS
CLIMATE...DS