477
FXUS61 KOKX 262338
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
638 PM EST Thu Dec 26 2024
.SYNOPSIS...
High pressure settles over the Northeast through Friday
morning, then moves offshore ahead of an approaching frontal
system. A warm front will then slowly work across the area
Saturday into Sunday, with a cold front moving through late
Sunday night into Monday. Another frontal system is forecast to
move into the area for the middle of next week.
&&
.NEAR TERM /THROUGH FRIDAY/...
High pressure settles over the Northeast tonight into Friday
morning before giving way to warm front approaching from the
southwest later in the day. Light winds and clear skies will
provide for another night of strong radiational cooling. Lows
will get back into the single digits well north and west of the
NYC metro. Elsewhere, lows will be in the teens and lowers 20s,
except in the mid and upper 20s for the NYC metro. Leaned
toward the colder MET/MAV MOS versus the deterministic NBM.
High pressure builds offshore Friday afternoon with increasing
high level clouds late in the day. Highs will top out close to
normal, in the mid 30s to around 40.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
A complex upper flow will feature the interaction of multiple
streams of the polar jet. Interaction of the southern and
northern branches will send a negatively tilted upper trough
across the Mid Mississippi Valley Friday and into the Great
Lakes Friday night. Warm advection precipitation out ahead of
the system approaches from the southwest and moves into the area
late Friday night, likely not until after midnight. At the same
time, high pressure continues to work away from the area and
into the north Atlantic. The orientation of the high does not
favor strong cold air damming to the lee of the Appalachians,
but at the same time the return southerly flow is very weak
Friday night. However, it`s plenty warm aloft for all rain. The
main concern will be how quickly the low-level cold air erodes,
especially well inland. Most coastal locations by the time the
precipitation begins will be above freezing. Inland areas north
and west though could see a 2-4 hour window of light freezing
rain before rising above freezing mid to late morning Saturday.
The greatest threat for ice accretion will be across interior NE
NJ and up into the Lower Hudson Valley (north of I-87 and west
of I-84). These locations could see several hundredths of an
inch of ice accretion, with possibly a bit more north and west
of I-84 in Orange county. Confidence is not high enough at this
time to issue a Winter Weather Advisory, largely due to the
timing of the rain Friday night and surface temperatures.
All locations will transition to all rain by mid to late
morning Saturday with generally light rain. There may even be a
time period late in the day where the warm advection wanes and
there is some light rain and/or drizzle.
Lows Friday night will range from the upper 20s inland, to the
lower and mid 30s at the coast. These lows will occur during
the first half of the night before temperatures start rising.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A very unsettled pattern is expected for the long term with multiple
systems moving through. The NBM was closely followed with some
subtle adjustments.
A warm front will be in the vicinity of the area Saturday night and
slowly push northward through the day on Sunday. This will likely be
the focus for some rain showers over much of the area, but intensity
should be light with showers generally more scattered than
widespread. The area moves into the warm sector of an intensifying
low pressure system over the Ohio Valley into the Great Lakes
region. This may result in additional scattered shower activity,
though depending on how deep into the warm sector the area gets,
some areas may be dry during the day on Sunday, especially areas to
the south.
By Sunday night, the strong cold front begins to approach the area
from the west. As the low pressure strengthens and pushes north into
Southeastern Canada to the northwest, the cold front will slowly
make its way through the area into Monday. There area some timing
differences among global models where the more progressive GFS has
the front clearing the area by Monday afternoon where the CMC and
ECMWF take more time for the front to clear, eventually passing
through by evening on Monday. The only difference this should make
it the timing of the ending of the precipitation. Either way, light
to moderate rainfall is expected for much of the area Sunday night
and through much of the day on Monday with persistent strong
southerly flow advecting warmer air into the area. High temperatures
both Sunday and Monday are expected to be in the middle 50s, well
above average for this time of the year.
The system exits the area by Tuesday allowing for high pressure to
move overhead before quickly departing as another moderately strong
albeit much quicker low pressure system moves in from the southwest
into the middle of next week.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
High pressure remains over the area thru Friday. A warm front
approaches Friday Night.
VFR expected through Friday evening push. There is a low
probability of MVFR cigs sneaking into S coastal terminals Fri
aft/eve.
Light N/NNE to variable winds through Friday morning, becoming
light S flow aft 18Z Fri. Speeds below 7kt thru the TAF period.
NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
No unscheduled amendments expected. Low prob for MVFR cig
development for Fri eve push. Winds will likely average N/NE 5
kt or less for Fri AM push, and S 5 kt or less for Fri eve push.
OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...
Friday Night-Saturday Morning: Becoming MVFR/IFR with light
rain developing from west to east for city/coastal terminals
aft midnight. -FZRA possibly developing aft midnight thru Sat
AM push for KSWF. Slight chance for a period of -FZRA at KHPN
and KBDR.
Saturday into Sunday: Period of -RA & DZ likely with IFR.
Sunday Night into Mon Morning: RA/+RA and IFR. Chance of LLWS.
S winds with gusts abv 30kt.
Monday Afternoon: Becoming VFR with W winds.
Tuesday: MVFR or lower in -RA likely.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
High pressure will remain across the area into Friday before
giving way to a frontal system over the weekend. Winds and seas
are forecast to remain below SCA criteria through Saturday.
The frontal system will move across the area waters Sunday and
Monday, with SCA conditions returning Sunday night and Monday as
winds increase to near 25 kt and seas build to 5-7 ft.
Conditions fall below SCA levels on Tuesday, however this may be
short lived as another frontal system approaches for Tuesday
night and Wednesday.
&&
.HYDROLOGY...
-- Changed Discussion --
A frontal system will bring rainfall to the area late Friday
night into Monday AM. The heaviest rain will likely fall late
Sunday into Monday AM ahead of a strong cold front.
There is the potential for 1-2" of rainfall, primarily north
and west of NYC. While WPC has some portions of the area in a
marginal risk for excessive rainfall, there are no hydrologic
concerns at this time.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...DW/MW
NEAR TERM...NV/DW
SHORT TERM...DW
LONG TERM...MW
AVIATION...NV
MARINE...DW/MW
HYDROLOGY...DW/MW