000
FXUS61 KOKX 192038
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
338 PM EST Fri Jan 19 2024

.SYNOPSIS...
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Low pressure departs to the east tonight. Arctic high pressure then builds in through the weekend, and slides to the south of Long Island Monday. A frontal system impacts the area Tuesday through Wednesday night, with another quickly following from the southwest for Thursday and Friday.
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&& .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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The Winter Weather Advisory has been canceled. An SPS has been issued for the entire area for some lingering light snow through the evening commute as well as the potential for icy conditions through tonight. With temperatures dropping into the teens, any residual moisture will freeze. Untreated surfaces will become icy. The heaviest snowfall has already fallen and only lingering light snowfall is expected through early this evening. Current MRMS and OKX radar show returns lightening across the area. The low continues to be seen quite well on visible satellite imagery and is now about 375 nm southeast of Long Island. An inverted trough stretches back west, well to our south. Attention now turns to arctic high pressure that will build in from the west. This will bring us the coldest airmass of the season. As the ~1040mb high builds in, the exiting low strengthens. This will place the area under a tight pressure gradient. Winds will increase to about 15 to 20 mph tonight. This combined with the cold temperatures will cause wind chill values to be in the single digits tonight, with sub zero values across the interior.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
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The high continues to build in on Saturday, with the area remaining in a tight pressure gradient. This will allow for cold conditions Saturday and Saturday night. Highs on Saturday top out in the low to mid 20s. With winds staying around 15 to 20 mph, max wind chill values during the day will be in the low teens, meaning most of the day will feature single digit wind chill values. Saturday night will similar to Friday night, just a few degrees colder. Some sub zero wind chill values could be seen across eastern Long Island. Skies start to slowly clear Saturday night as the upper level trough axis finally shifts east.
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&& .LONG TERM /SUNDAY THROUGH FRIDAY/...
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The long term period will feature below normal temperatures continuing, Sunday into Monday, with a warm up beginning Monday night, and temperatures rebounding to above normal for Tuesday through Friday. Arctic high pressure continues to build toward the region from the west Sunday, and then builds to the south, off the Mid Atlantic coast, Monday night into Tuesday. Sunday and Sunday night temperatures will be 5 to near 10 degrees below seasonal normals. While warm advection does not set up until Tuesday, with the approach of a warm front, the airmass will be modifying during Monday as temperatures rise to near normal levels. A weak surface trough, or cold front, with little moisture, moves into the region early Tuesday and becomes nearly stationary during the day. Warm advection then sets up later Tuesday and continues through the week as the frontal boundary remains in the vicinity. A series of southern stream shortwaves will bring waves of low pressure along the front Tuesday into Wednesday, with another Thursday into Friday. With an highly anomalous warm airmass moving into the region, with temperatures rising to 10 to 15 degrees above normal, used a blend of the NBM, and 75th percentile for temperatures Tuesday through Friday to better capture the unusual warmth. Precipitation will be mostly rain across the region, with a mix of rain and snow inland Tuesday into early Wednesday.
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&& .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
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Low pressure pulls away from the region tonight as high pressure gradually builds in from the west through the weekend. Widespread MVFR/IFR conditions will persist through early evening. Light snow (-SN) is resulting in visibilities anywhere from 1 to 3 miles for much of the area and should gradually improve as the light snow continues to diminish through the evening. Light snow and flurries will end between 22-00Z. VFR conditions expected around or shortly after 00Z for the NYC terminals with eastern terminals going VFR a few hours later. NNE winds around 10kt will veer to the N by early evening, then NW after 00Z. Second half the night and Saturday will feature gusts up to 20-25 kt. NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Amendments possible for the timing of improving flight categories through this evening. OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY... Saturday afternoon-Sunday...Mainly VFR. N-NW wind gusts 20-30kt. Monday...VFR. Tuesday...Mainly VFR. Possible MVFR or lower in any rain/snow showers. Wednesday...MVFR or lower possible in rain. 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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A Small Craft Advisory is in effect for all waters tonight through Saturday night. The Saturday night Gale Watch has been converted to a Small Craft Advisory as wind gusts have trended down. Winds in the SCA will generally be 25 kt, with 25 to 30 kt expected late Saturday into Saturday night. With a cold airmass building in, Air temperatures are forecast to be in the teens to 20s and water temperatures in the lower upper 30s to lower 40s. This combined with the forecast winds will allow for a chance of light vessel ice accumulation starting tonight. This will mainly be across the ocean zones and the LI Sound. High pressure will be building in from the west Sunday as low pressure departs to the northeast. A strong pressure gradient force will remain across the waters Sunday as a strong and gusty northwest flow persists. Small craft advisory gusts will likely be on-going Sunday morning across the forecast waters. Ocean seas may be near 5 feet early Sunday morning, then subside in the northwest flow. Winds and gusts diminish through the day as the high builds closer to the waters. And during Sunday evening gusts will likely fall below 25 knots. The high shifts to the south of the waters Monday with a cold front approaching from the north. A west/southwest flow will be increasing through Monday, and by late in the day, or early Monday evening gusts and seas on the ocean waters may reach SCA levels. There is some uncertainty as to how much mixing will occur over the waters as warmer air flow in and keeps a low level inversion in place. Early Tuesday gusts and seas fall below SCA levels as a weak cold front becomes nearly stationary in the vicinity. Winds and seas then remain below advisory levels on all the waters late Tuesday through Wednesday.
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&& .HYDROLOGY...
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No hydrologic impacts are expected through the end of next week.
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&& .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory from midnight tonight to 6 AM EST Sunday for ANZ331-332-335-338-340-345. Small Craft Advisory until 6 AM EST Sunday for ANZ350-353-355.
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&& $$ SYNOPSIS...MET/JT NEAR TERM...JT SHORT TERM...JT LONG TERM...MET AVIATION...MW MARINE...MET/JT HYDROLOGY...MET/JT