Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 042040 AFDOKX Area Forecast Discussion National Weather Service New York NY 340 PM EST Sun Dec 4 2016 .SYNOPSIS...
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High pressure moves offshore overnight as a weak frontal system moves in for Monday morning. High pressure briefly returns Monday night into early Tuesday, before giving way to low pressure passing well south of our region Tuesday night into Wednesday. A rather strong cold front passes through Thursday into Thursday night bringing unseasonably cold weather for Friday into the weekend a well as strong gusty winds.
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&& .NEAR TERM /UNTIL MIDNIGHT TONIGHT/...
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Clear skies and light winds will set the stage for rapid radiational cooling in areas away from the urban corridor.
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&& .SHORT TERM /MIDNIGHT TONIGHT THROUGH MONDAY NIGHT/...
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Latest NWP suggest forecast is on track with very few changes in for today`s update from previous. PCPN reaches the Hudson around 09Z and rapidly expands east. Have increased POPs to Categorical 80% for the morning rush in all zones. Snow inland...with some RASN for the CT Coast back to NE NJ. Rain for City and Long Island...some some wet flakes may mix in there too. On Long Island with the radiational cooling early tonight, surface temps may be below freezing - so some icing is possible. Have issued a Special Weather Statement (SPS) for the wintry weather during the morning rush. Temps warm quickly in the morning. Highs in the 45-50 degree range - or about 3-4 degrees warmer than previous as the PCPN is quick to depart. All NWP appears very consistent with this system. QPF is around 0.15" - again very consistent. High pressure returns for Monday night.
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&& .LONG TERM /TUESDAY THROUGH SUNDAY/...
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A progressive flow will prevail across the continental United States at the beginning of the work week. Dry weather at the start of the extended period will become wet as a southern stream shortwave phases with a northern stream negative trough by 12Z Tuesday. Upper ridging quickly flattens Tuesday. With the progressive flow opted to bring probabilities into the region by Tuesday afternoon, more in line with the faster GFS. The northern and southern stream systems to remain distinct and the area likely will be in a cull. Light rain and possibly drizzle will continue through Wednesday. Another shortwave, moving into the Pacific northwest during Tuesday will rotate through the northern stream trough digging the trough, becoming nearly fully latitudinal during Thursday. Again opted for the faster GFS with the timing of this next system as the flow remains progressive. As the shortwave moves off the northern coast rapid deepening of the low will occur Thursday night into Friday. There is still some uncertainty with the depth of the low and how quickly the low moves off the northeast coast. Again the GFS is faster and deeper with the low. Some of the coldest air of the season is possible behind the cold front with temperatures as much as 10 degrees below normal Friday night into Saturday night.
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&& .AVIATION /21Z SUNDAY THROUGH FRIDAY/...
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High pressure remains in control this evening before moving offshore tonight ahead of an approaching frontal system. VFR until around 06Z when conditions begin to lower to MVFR as light precipitation overspreads the area. Expecting primarily rain across the city and coastal terminals. Farther inland, precipitation at KSWF should remain all snow while KHPN may start as a rain/snow mix before transitioning to all rain. N-NNW winds this evening will become light overnight. Winds then shift to the SE early Monday morning and then SW Monday afternoon at around 10 kt as the system approaches and crosses the area. .OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY... .Monday afternoon...Becoming VFR. .Tuesday...VFR early, then MVFR possible with a chance of light rain or drizzle. .Tuesday night-Wednesday...IFR in drizzle and light rain. .Thursday...MVFR possible with a chance of rain. .Friday...VFR.
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&& .MARINE...
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High pressure moves east of the waters tonight. A weak frontal system moves through Monday, but winds and seas remain relatively tranquil. High pressure will be exiting the forecast waters Tuesday as a low approaches from the southwest and then moves off the Mid Atlantic coast Tuesday night, remaining well south of the forecast waters Wednesday. Winds and seas are expected to remain below small craft with the exception of the possibility of seas nearing 5 FT on the far outer ocean zones late Tuesday night through Wednesday as the low passes. Thursday into Thursday night another frontal system will move through the forecast waters with a strong cold passing through Thursday night. Strong and gusty northwest winds will develop behind the front with the potential for gale conditions Thursday night into Friday night across all the forecast waters.
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&& .HYDROLOGY... No hydrologic impacts are anticipated the next 7 days. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...Tongue NEAR TERM...Tongue SHORT TERM...Tongue LONG TERM...MET AVIATION...FEB MARINE...MET/Tongue HYDROLOGY...Tongue

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