Area Forecast Discussion
Issued by NWS Upton, NY

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450 FXUS61 KOKX 220532 AFDOKX Area Forecast Discussion National Weather Service New York NY 132 AM EDT Sun Sep 22 2024 .SYNOPSIS...
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Offshore low pressure continues to slowly depart to the southeast tonight through Sunday. Meanwhile, high pressure noses in from the northeast and remains in control through at least Tuesday. A frontal system may then approach on Wednesday and move across on Thursday, High pressure may slowly return on Friday and Saturday.
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&& .NEAR TERM /UNTIL 6 AM THIS MORNING/... The forecast is mainly on track. Only bumped up low temps over parts of LI and SE CT a little based on recent and anticipated cloud cover. Offshore low pressure is centered about 300nm southeast of the area. The low will continue to slowly depart to the southeast tonight, while high pressure centered well to our northeast noses into the area. A slight chance of showers for far eastern portions of LI and CT remains this evening, then dry overnight. As the pressure gradient slowly slackens over the area tonight, winds will lower a bit. However, can still expect 10 to 15 mph sustained winds, with gusts up to 20 mph for far eastern LI and CT. Given the elevated winds, stuck with the NBM for lows tonight. Not expecting good radiational cooling conditions. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/... High pressure continues to build in on Sunday and will remain in control through at least Tuesday. Aloft, heights rise on Sunday as an upper level ridge builds in. The ridge axis will pass overhead early Monday. This pattern will bring dry conditions to end the weekend and start next week. It will also bring a slight cooling trend. Highs will be right around normal on Sunday and then likely just below normal on Monday. Stuck with NBM for the most part for temperatures. Blended some MOS guidance and the NBM 10th percentile across the northern interior for Sunday night where winds will be lighter and dewpoints a bit lower. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Key Points: * Dry into daytime Tuesday. * Possible showers Tue night through Thu night with an approaching frontal system. * Uncertainty as to whether shower chances may continue into Fri or Sat. * Temperatures near to slightly below normal from Mon-Thu, with moderation to slightly above normal Friday and Saturday. Forecast mostly follows NBM, but with somewhat lower PoP and sky cover until the current dry-begets-dry pattern truly shows signs of breaking. High pressure nosing down from the northeast on Mon should hang on into at least Tue, then start slowly introducing PoP to areas W of NYC Tue night, also to the NYC metro area and western Long Island/CT daytime Wed, and throughout Wed night/Thu. Model disagreement remains especially from that point on as to whether the frontal system will even clear the area on Fri with high pressure building from the N per 12Z GFS, or if low pressure will develop nearby and then move slowly away per 00Z ECMWF. Have slight chance PoP for Fri and dry conditions for Sat, but these are uncertain. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/...
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High pressure ridges in from the northeast today. MVFR to VFR at KGON, otherwise VFR for all the terminals, bu still a low chance of MVFR cigs from approx 08-13z for all but KSWF. NE winds around 10kt for the pre-dawn hours, but a little stronger at KGON with some gusts around 20kt. Gusts 20-25 kt returning by noon, mainly east of the city terminals. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Can not rule out an occasional gust to 20kt mainly for KJFK and KLGA starting late morning today, with this possibility lasting through the afternoon. Brief MVFR possible from approx 08-13z. OUTLOOK FOR 06Z MONDAY THROUGH THURSDAY... Late tonight: VFR, but possibly MVFR east of the city. Monday: VFR, except chance of MVFR east of the city. Tuesday and Wednesday: Mainly VFR, with pockets of MVFR in SHRA. E/NE G15-20kt possible at the coastal terminals. Thursday: Chance of MVFR in SHRA. 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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Offshore low pressure continues to bring gusty winds to the eastern waters and 5+ ft swell to the ocean waters. The low will slowly drift southeast, with 25 kt gusts likely ending everywhere by late tonight except on the ocean east of Moriches Inlet. However, Small Craft Advisory conditions will continue on all ocean waters for some time with 5+ ft seas. Seas peak tonight through Monday at 6 to 8 ft. The Small Craft Advisory has been extended into Monday, but will likely need to be extended further over the next several forecast cycles. An extended period of hazardous ocean seas and rough conditions at the inlets should remain through at least Wed. Seas may start to diminish below 5 ft Wed night into Thu, but could come back up again later on Thursday.
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&& .HYDROLOGY... There are no hydrologic concerns through Tuesday. Basin avg QPF from Wed into Thu night should range from 3/4 to 1 inch. Only minor nuisance impacts expected at most, mainly on Thu. && .TIDES/COASTAL FLOODING... Coastal flooding will continue into Monday, but impacts and areal coverage will be on the downswing as astronomical tides continue to lower. The offshore low responsible for the easterly swell that has helped pile water into the area will slowly work southeast through early next week. There will be one more cycle of widespread coastal flooding on Sunday with the potential for localized moderate, especially for the south shore back bays of Nassau. The high tide cycles tonight and Sunday night will feature more localized minor flooding for locations adjacent to Lower NY Harbor and western LI Sound. However, an advisory is in effect for late tonight for the south shore back bays of Queens and Nassau where minor flooding will be a bit more widespread. The south shore back bays of western LI will likely have issues through Monday. As for surge guidance, leaned toward a blend of the TOFs, ETSS and Steven`s 50th percentile. However, Steven`s guidance has been overdone in the south shore back bays of LI, likely due to no wind forcing (E/SE winds). This has been accounted for with some downward adjustment. This was particularly noticeable over the eastern bays of LI, where there has been little if any flooding noted. The high rip current risk continues through Monday evening due to a prolonged period of easterly swells. && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Coastal Flood Advisory from noon today to 5 PM EDT this afternoon for CTZ009-010. NY...Coastal Flood Advisory from noon today to 5 PM EDT this afternoon for NYZ071-073-078-176-177. Coastal Flood Advisory from 10 AM this morning to 4 PM EDT this afternoon for NYZ072-074-075-080-178-179. High Risk for Rip Currents through Monday afternoon for NYZ075-080- 081-178-179. Coastal Flood Advisory until 2 AM EDT early this morning for NYZ178-179. NJ...Coastal Flood Advisory from 10 AM this morning to 4 PM EDT this afternoon for NJZ006-106-108. MARINE...Small Craft Advisory until 6 PM EDT Monday for ANZ350-353-355.
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&& $$ SYNOPSIS...BG/JT NEAR TERM...JC/JT SHORT TERM...JT LONG TERM...BG AVIATION...JC MARINE...BG/JT HYDROLOGY...BG/JT TIDES/COASTAL FLOODING...