Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 262022 AFDOKX Area Forecast Discussion National Weather Service New York NY 422 PM EDT Fri May 26 2017 .SYNOPSIS...
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Low pressure departs the New England Coast tonight as weak high pressure settles over the region. A weak wave of low pressure passes to the south Saturday into Saturday night. A series a weak waves of low pressure or troughs will move through the northeast Sunday through Thursday. A cold front is expected to move through the region Friday.
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&& .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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Weak instability and heating within deep cyclonic flow has developed a few isolated showers this afternoon. Coverage looks to remain isolated. With loss of heating this evening and now real defined source for lift, any showers will dissipate. Heights aloft will continue to rise tonight as low pressure continues to depart the New England coast. Clouds will dissipate somewhat, but there is enough low level moisture for at least partly cloudy skies overnight. Lows will range from the lower 50s inland to the middle and upper 50s near the coast. There is a high risk of rip currents into this evening.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
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Main concern for Saturday is with a convectively induced shortwave that is currently located over the Upper Mississippi river valley. Models have not been handling this energy very well as depicted with Dprog/Dt at H5. However, it appears they are beginning to handle this feature better with just some timing differences overall. The shortwave is forecast to quickly traverse through the Ohio Valley tonight and then towards the region on Saturday. Prefer to follow a blend of the NAM, 3-km NAM and ECMWF, which brings the shortwave offshore late afternoon and early evening. The GFS, GEFS, and CMC are a bit slower and do not bring it offshore until overnight Saturday. Have elected to go with slight chance PoPs, mainly for the western half of the area, as better lift and moisture appears to pass to the south of the region. Otherwise, mostly cloudy skies are expected with high temperatures around 70 in NYC and middle and upper 60s elsewhere. Clouds gradually decrease Saturday night as ridging builds aloft. Lows will be near normal.
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&& .LONG TERM /SUNDAY THROUGH FRIDAY/...
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With a delay in the timing of the northern stream longwave trough and the shortwave rotating through the base of the trough have delayed the probabilities of showers until late in the day Sunday; and mainly across the far west and southwest zones. Aloft, an upper ridge axis will still be west of the region at 12Z Sunday with heights rising until the afternoon. At the surface a weak high will be moving off the coast. Then as the shortwave moves into the region probabilities increase Sunday night into Monday. At the surface the will be weak forcing as a weak cold front moves into the region. A thermal ridge also moves into the area Monday afternoon. Monday may be one of the warmer days of next week. With weak surface based instability, and increasing aloft along with increasing CAPE will have thunderstorms Monday afternoon into the evening. There is still some uncertainty with the timing of the upper trough and shortwave for Sunday and Monday. The closed upper low and longwave trough will be slow to move east through the week as a series of shortwaves rotate through the trough, while at the surface weak lows, or troughs move through the area. There remains a lot of uncertainty with the timing and placement of the systems through the upcoming week. And, there will be a prolonged period of unsettled weather. Will carry slight chance to low chance probabilities through the week, although there may be periods of dry weather.
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&& .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
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Low pres will track SE of Nova Scotia tonight...and then out to sea Saturday. VFR. Isolated showers into early evening with possible brief MVFR and gusts to 30 kt. Gusty W/WNW winds to 25 kt into early evening push...diminishing into tonight. Light NW winds for Sat morning push. S/SE seabreeze development Sat afternoon. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/www.weather.gov/zny/n90 KJFK TAF Comments: Winds will waver between 290 and 320 magnetic late this afternoon into eve. Gusts to 25 kt likely into start of evening push. Isolated shower possible into this evening with gust to 30kt. KLGA TAF Comments: Winds will waver between 290 and 320 magnetic late this afternoon into eve. Gusts to 25 kt likely into start of evening push. Isolated shower possible into this evening with gust to 30kt. KEWR TAF Comments: Winds will waver between 290 and 320 magnetic late this afternoon into eve. Gusts to 25 kt likely into start of evening push. Isolated shower possible into this evening with gust to 30kt. KTEB TAF Comments: Winds will waver between 290 and 320 magnetic late this afternoon into eve. Gusts 20 to 25 kt possible into start of evening push. Isolated shower possible into this evening with gust to 30kt. KHPN TAF Comments: W/WNW gusts 20 to 25 kt possible into start of evening push. Isolated shower possible into this evening with gust to 30kt. KISP TAF Comments: W/WNW gusts 20 to 25 kt possible into start of evening push. Isolated shower possible into this evening with gust to 30kt. .OUTLOOK FOR 18Z SATURDAY THROUGH TUESDAY... .Saturday...MVFR cigs possible. S/SE afternoon sea breeze expected for coastal terminals...likely into KEWR/KTEB. .Saturday Night-Sunday...MVFR/IFR. E/SE winds. .Sunday Night-Monday...MVFR/IFR likely in rain. E winds. .Tuesday...Improving to VFR. S/SE winds.
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&& .MARINE...
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Southerly swell continues on the ocean waters through tonight. Seas will subside overnight as the swell diminishes. 5 ft seas could linger east of Moriches inlet through Saturday morning, so have extended the SCA to account for this. Otherwise, Sub-SCA conditions are forecast on the waters through Saturday night. A weak surface pressure gradient force will be across the forecast waters Sunday through Wednesday as a series of weak lows or troughs move through the waters with low pressure remaining north of the Great Lakes into Tuesday night. The lows then moves slowly east through Friday. Winds and seas will remain below small craft advisory levels Sunday through Wednesday.
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&& .HYDROLOGY...
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No hydrologic impacts into early next week.
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&& .TIDES/COASTAL FLOODING...
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The threat for minor coastal flooding will continue for the nighttime high tides though Memorial Day Weekend. Widespread minor coastal flooding is expected for the southern bays of Western LI and Jamaica Bay tonight...with brief and localized minor flooding for western Long Island Sound, lower NY/NJ Harbor, and eastern Great South Bay. Despite high astronomical tides the offshore flow will be a limiting factor to surge tonight. For Saturday Night...although astronomical tides lower...surge will likely be on the increase. Widespread minor coastal flooding is expected once again for the southern bays of NYC/Western LI...and also for coastal Fairfield and Westchester counties. Brief and localized minor flooding is likely for the rest of western Long Island Sound, lower NY/NJ Harbor, and eastern Great South Bay. Surge likely increases for Sun into Mon...which will continue a similar threat for coastal flooding despite lower astronomical tides.
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&& .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Coastal Flood Advisory from midnight Saturday night to 3 AM EDT Sunday for CTZ009. NY...Coastal Flood Advisory from midnight Saturday night to 3 AM EDT Sunday for NYZ071. High Rip Current Risk until 9 PM EDT this evening for NYZ075- 080-081-178-179. Coastal Flood Advisory from 8 PM this evening to 1 AM EDT Saturday for NYZ178-179. Coastal Flood Advisory from 9 PM Saturday to 2 AM EDT Sunday for NYZ075-178-179. NJ...None. MARINE...Small Craft Advisory for hazardous seas until 6 AM EDT Saturday for ANZ353-355. Small Craft Advisory for hazardous seas until 11 AM EDT Saturday for ANZ350.
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&& $$ SYNOPSIS...DS/MET NEAR TERM...DS SHORT TERM...DS LONG TERM...MET AVIATION...NV MARINE...DS/MET HYDROLOGY...DS/MET TIDES/COASTAL FLOODING...NV

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