Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 162106 AFDOKX Area Forecast Discussion National Weather Service New York NY 406 PM EST Tue Jan 16 2018 .SYNOPSIS...
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Low pressure develops along the Mid Atlantic coast this evening and then passes near or just east of Long Island on Wednesday before moving up the coast into the Canadian Maritimes Wednesday night. High pressure will then build to the south through Friday and move into the western Atlantic this weekend. A cold front then passes through Monday night into Tuesday morning.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Models have continued to trend toward a low track that is closer to the coast and thus a warmer solution. A prolonged period of SE winds in the low levels ahead of the developing low off the Mid Atlantic coat tonight will gradually increase temperatures in the boundary layer. This warming appears to be sufficient enough for primarily a rain event along the immediate coast. At the same time, interior sections of the Lower Hudson Valley and southwest Connecticut will be the recipients of a moderate snowfall event with amounts around warning criteria. A Winter Storm Warning has been issued for northern portions of the Lower Hudson Valley with a winter weather advisory across the remainder of the Lower Hudson Valley and interior sections of northeast New Jersey and Connecticut. The winter weather advisory has been cancelled along for coastal Connecticut and NYC metro. An amplifying upper trough moving across the Ohio valley tonight will allow for the forcing to shift to the Mid Atlantic coast tonight, with low pressure developing and tracking northeast to near or just southeast of Long Island in the morning. The transition of energy is slow enough that an inverted trough to the NW of the low track, extending back into the Hudson Valley of New York, will allow for an influx of warmer air ahead of the low. Greatest uncertainty resides in the northern extend of this warm air and how far the rain/snow line works. Right now, it appears that it should remain all snow just north of HPN and DXR, and about 10 to 20 miles to the north and west of the I-95 corridor in New Jersey. The steadiest precipitation develops after midnight across the region. Temperatures will remain nearly steady overnight and even slowly rise. Lows will range from the upper 20s in the interior to the mid 30s along the coast.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
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Low pressure near Long Island in the morning lifts northeast during the day and up into the Canadian Maritimes by Wednesday night. Precipitation shuts down across most of the area by late morning/early afternoon and perhaps ends as period of snow at the coast. Highs will top out in the mid to upper 30s with NW winds developing on the backside of the storm. Gust up to 20 mph develop late in the day and possibly linger into first half of the night. Cold air will follow for Wednesday night with lows in the teens inland and around 20 at the coast. This is slightly below normal.
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&& .LONG TERM /THURSDAY THROUGH TUESDAY/...
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Surface high pressure will build to our south on Thursday and Friday. Meanwhile, an upper trough shifts through with some shortwave energy Thursday night into Friday. Moisture looks insufficient for any PCPN, so dry weather is expected. Highs a few degrees below normal for Thursday, returning to near normal on Friday. Ridging aloft will then keep the weekend dry with warming temperatures. Low pressure enters the Great Lakes Region Sunday night, eventually tracking through Quebec on Tuesday. Some warm advection PCPN may reach some of the northern zones Sunday night into Monday morning, which could be in the form of a wintry mix. A cold front otherwise approaches with increasing chances of rain during the afternoon and night. Some timing differences still exist among the global models with the cold front passage, so have capped PoPs at chance through Tuesday morning. Rain chances otherwise diminish Tuesday afternoon with dry weather likely returning Tuesday night. Temperatures Sunday through Tuesday will remain above normal.
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&& .AVIATION /20Z TUESDAY THROUGH SUNDAY/...
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High pressure moves off the Northeast coast tonight as a developing coastal low moves towards the area. By Wednesday, the coastal low tracks northeastward towards the Canadian Maritimes. Conditions expected to gradually lower to MVFR this evening, then lower to IFR overnight as precipitation becomes steadier. Precipitation will largely hold off until after sunset, except at KSWF where occasional snow showers will be possible through the evening. Expect all snow at KSWF. A rain/snow mix or perhaps all rain will be possible for the remainder of the terminals, with all rain most likely at KISP and KGON. All sites may receive a quick accumulation of snow as the system departs Wednesday morning. Winds will be somewhat variable through the night, but generally less than 10 kt. As the system departs on Wednesday, winds become WNW and increasingly gusty through the day. NY Metro Enhanced Aviation Weather Support... Detailed information...including hourly TAF wind component fcsts can be found at: http:/www.weather.gov/zny/n90 KJFK TAF Comments: Winds generally light and variable at times. Timing of the onset of MVFR conditions may be an hour or two later than forecast. Low confidence in precipitation type with snow totals less than 1 inch possible through Wednesday. KLGA TAF Comments: Winds generally light and variable at times. Timing of the onset of MVFR conditions may be an hour or two later than forecast. Low confidence in precipitation type with snow totals less than 1 inch possible through Wednesday. KEWR TAF Comments: Winds generally light and variable at times. Spotty IFR ceilings possible this evening. Low confidence in precipitation type with snow totals around 1-2 inches possible through Wednesday. KTEB TAF Comments: Winds generally light and variable at times. Spotty IFR ceilings possible this evening. Low confidence in precipitation type with snow totals around 1-3 inches possible through Wednesday. KHPN TAF Comments: Winds generally light and variable at times. Timing of the onset of MVFR conditions may be an hour or two later than forecast. Low confidence in precipitation type with snow totals around 2-4 inches possible through Wednesday. KISP TAF Comments: Winds generally light and variable at times. Timing of the onset of MVFR conditions may be an hour or two later than forecast. Primarily rain expected through occasional mixing of snow possible, mainly as the system departs Wednesday morning. Snow totals minimal. .OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY... .Wednesday...Conditions gradually improving to VFR from west to east. WNW winds 10-15KT with gusts up to 25 KT. .Wednesday night-Thursday...VFR. NW-WNW winds G15-25KT possible. .Thursday night-Friday...VFR. WSW-W winds G15-20KT possible. .Saturday-Sunday...VFR.
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&& .MARINE...
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SCA in effect for the ocean waters as seas remain 4-5 ft. Ocean seas increase a bit more tonight. Flow returns to a NW direction and begins to gust late on Wednesday. SCA conditions continue on the ocean for Thursday through Friday morning, then sub-advisory conditions are expected for a brief period Friday afternoon and night. Winds and seas then pick up with marginal advisory conditions on the ocean during Saturday and Saturday night. A weaker pressure gradient then returns relatively tranquil conditions for Sunday.
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&& .HYDROLOGY... No significant hydrologic impacts are expected. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) is off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Winter Weather Advisory from midnight tonight to 1 PM EST Wednesday for CTZ005>008. NY...Winter Weather Advisory until noon EST Wednesday for NYZ069- 070. Winter Storm Warning until noon EST Wednesday for NYZ067-068. NJ...Winter Weather Advisory until noon EST Wednesday for NJZ002- 004-103>105-107. MARINE...Small Craft Advisory from midnight tonight to 6 AM EST Thursday for ANZ355. Small Craft Advisory until 6 AM EST Thursday for ANZ350-353.
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&& $$ SYNOPSIS...JC/DW NEAR TERM...DW SHORT TERM...DW LONG TERM...JC AVIATION...MD MARINE...JC/DW HYDROLOGY...JC/DW EQUIPMENT...//

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