000
FXUS61 KOKX 132323
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
623 PM EST Sat Jan 13 2024
.SYNOPSIS...
-- Changed Discussion --
Deep low pressure remains in southeastern Canada tonight. An
Arctic frontal passage occurs on Sunday. A cold airmass will
settle in for the week. There will be chances for snow around
Tuesday, and again at the end of the week.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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The fcst is on track. Temperatures will continue to cool
tonight with west-southwesterly winds. Skies look to clear as
drier air moves in with lows right around freezing for most.
Some interior areas will dip into the upper 20s.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Upper low pressure will remain, and meander, across Eastern Canada
tonight through Monday morning. A rather strong shortwave rotates
into the upper low late tonight and moves across the region Sunday
with an Arctic cold front passing through. A chance of snow showers
remains possible mainly Sunday afternoon.
CAMs have been signaling the chance for snow squalls in the early
afternoon over the last three synoptic run times with the 6Z, 12Z
and 18Z models. They portray a sharp pressure and temperature
gradient with strong cold air advection behind a line of
reflectivity expected to push through. Should the squall materialize
tomorrow, it will bring brief moderate to heavy snow and gusty
winds. This will reduce visibility and may cause a hazardous
situation for anyone traveling on the road. Before the squall,
temperatures are forecasted to be in the low-40s to upper-30s for
coastal areas. This means, for most, a flash freeze looks less
likely, with strong winds associated with FROPA drying out the
roadways before they have a chance to freeze over. However, with
temperatures in the mid-30s around this time for interior areas of
southern Connecticut, dropping into the 20s after the passage of the
squall, a flash freeze and dangerous slick road conditions are
looking to be more of a concern.
Cold air filters in after the frontal passage bringing lows into the
upper-teens to lower-20s Sunday night.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
A 1050 high building into MT will ridge all the way to the Mid-
Atlantic on Mon. With a 980s low over Hudson Bay, a cold wly flow
will result locally. Wind chills based on the grids are calculated
to be in the single digits in the early mrng, then teens and 20s for
the day.
The focus then turns to snow chances, which are centered around Tue.
The cold air will be in place, but as of now, the upr trof has a bit
of a positive tilt, favoring either a light snow event or even a
complete miss out to sea. The NAM was an outlier, tucking a weak
secondary low in over LI. This soln was discarded for now as it is
too far out in time to have confidence in the soln. However, the
SREF mean, GEM, RGEM, and ECMWF are all W of GFS, so continued to go
with the blended approach of the NBM for pops, which are higher than
one might imagine if just looking at the operational GFS. The only
tweak was to limit the probs to the likely category to account for
the wide-right scenario.
For the grids, went with 3/4SM -SN, and accums around 1.5 inches.
Snowfall rates could be too low to allow max accums based on qpf, so
it could snow for several hours but not accumulate much until
pockets/bands of 1/2SM SN come thru. In general, expect a 1-3 or 2-4
inch snowfall with this event, unless the low spins up and a
stronger sys develops yielding higher amounts, or the steady pcpn
remains offshore yielding little to no accum.
Seasonably cold and dry on Thu. Stuck close to the NBM with the
typical local adjustments.
For Fri and Sat, yesterday it was the ECMWF producing a coastal low
with snowstorm potential, today it is the GFS. Both the EPS and GEFS
suggest low clustering over the Atlc in the Fri-Sat period. The EPS
is approximately 12 hours faster than the GEFS. Pops in the 40-50
percent range now, which is about a 10 percent increase from the
prev fcst, with the details highly uncertain about a week out.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
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Low pressure slowly lifts north of New England tonight. An arctic
cold front approaches Sunday morning and moves through Sunday
afternoon and early evening.
Gusty WSW-SW winds will continue tonight. Sustained speeds around 20
kt with gusts 30-35 kt will continue through 02z before slowly
weakening into the early morning hours. Gusts should end up
closer to 20-25 kt around day break and some outlying terminals
could see the gusts briefly end. SW flow increases through
Sunday morning ahead of the arctic front with sustained speeds
20-25 kt in the afternoon gusting 30-35 kt.
Mainly VFR conditions through the TAF period with the only exception
of potential for brief IFR or lower in snow showers or snow squalls
with the arctic cold front. Gusts 35-40 kt may accompany the fropa.
Winds shift to the W-WNW with potential for gusts around 35-40kt
late afternoon into early evening.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
A few peak gusts around 35-40 kt possible through 02z.
Gusts could become occasional 09-14z.
Peak gusts 40-45 kt possible at times Sunday afternoon and
evening.
OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...
Sunday night: VFR. W-WNW wind gusts 35-40 kt early, then decreasing
to near 20-25 kt mid to late evening. Gusts likely end after 04z.
Monday: VFR.
Monday Night-Tuesday. MVFR or lower possible with light snow late
Monday Night. IFR or lower with light snow on Tuesday, tapering off
in the evening.
Wednesday-Thursday: VFR. W wind gusts near 20-25kt on Wednesday.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Gale warning continues on all waters through tonight, and was
extended on the ocean waters through Sunday. After a lull in the
winds on the non ocean waters Sunday morning, gales may return
Sunday afternoon. With a break of several hours did not want to
extend the gales there attm. However, this break was a little longer
on the Sound, Harbor, and Bays.
In general, winds and seas blw SCA lvls Mon into Wed. There is a chc
seas linger around 5 ft on Mon on the ern ocean. Winds increase late
Wed, possibly hitting 25kt on the ocean. SCA cond are possible on
all waters, especially the ocean, Wed ngt into Thu on NW flow.
&&
.HYDROLOGY...
No hydrologic impacts expected thru Sat.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...None.
NJ...None.
MARINE...Gale Warning until 10 PM EST Sunday for ANZ331-332-335-338-340-
345-350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JMC/BR
NEAR TERM...JMC/BR
SHORT TERM...BR
LONG TERM...JMC
AVIATION...DS
MARINE...JMC/BR
HYDROLOGY...JMC/BR