Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 152117 AFDOKX Area Forecast Discussion National Weather Service New York NY 517 PM EDT Fri Sep 15 2017 .SYNOPSIS... A weak upper level disturbance will gradually dissipate over the area through Saturday. High pressure builds to the north into early next week. Meanwhile, tropical cyclone Jose will drift northward in the Western Atlantic waters this weekend into the middle of next week, with the potential for it to come close to the East Coast. Please refer to National Hurricane Center products for more details on Jose. By late week, high pressure builds across the area once again. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Isolated showers are expected to dissipate early this evening with the loss of daytime heating and instability. Moist air combined with light to calm winds should allow fog to develop, at least patchy in nature. Low temperatures will be above normal. A moderate risk for rip current development continues into this evening. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Weak high pressure remains over the area Saturday and Saturday night. At the same time, the flow aloft remains slightly cyclonic and with only weak shortwave energy. Thinking is that diurnally- driven iso showers develop, mainly over inland areas where higher CAPE values will be. Similar to tonight, any shower activity ends early in the evening followed by some areas of fog overnight. Temperatures Saturday and Saturday night will run above normal. There will be a moderate risk for rip current development along the Atlantic beaches for Saturday into Saturday night. && .LONG TERM /SUNDAY THROUGH FRIDAY/... PLEASE MONITOR NHC FORECASTS FOR OFFICIAL INFORMATION ABOUT TROPICAL CYCLONE JOSE: WWW.NHC.NOAA.GOV BEACH HAZARDS INCREASING THROUGH THIS WEEKEND Long period swells from tropical cyclone Jose will increase the threat for dangerous rip currents, high surf and dune erosion this weekend into the mid week. A blocking pattern is expected to develop as a long wave trough intensifies in the west, with the high pressure downstream amplifying across the east. Although seasonable temperatures will persist for Sunday, a gradual return to onshore flow as a surface high builds to the north and the tropical system approaches from the south will allow temperatures to be well below normal through at least mid week. Besides the potential for isolated afternoon showers and thunderstorms mainly north and west of the city on Sunday, all eyes will turn to the developing tropical system that at the moment is still well south of the area. Once again, considerable uncertainty exists with the expected track of tropical cyclone Jose. The track will largely determine the intensity of any winds, coastal impacts and rain. As of now, the official NHC wind speed probabilities now show a 10 to 20 percent chance of tropical storm force winds (39 to 73 mph) developing on Tuesday. It`s important to note that typical forecast track errors 4 to 5 days out generally range from around 175 to 225 miles, respectively. Despite the uncertainty, long period swells ahead of the system will allow surf to build and increase the risk of dangerous rip currents. The NWS will continue to monitor the progression of Jose closely. Please stay tuned for subsequent updates. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
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A trough of low pressure will remain across this evening. Mainly VFR through the evening. S-SE winds will remain 10 kt or and become light and variable overnight. Isolated shower still possible NW of the metro terminals. Patchy stratus and fog should redevelop tonight with the best chance outside of the NYC terminals. Any MVFR or IFR conditions should improve between 14-16z Saturday morning. 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: Low chance for MVFR/IFR stratus and fog overnight. KLGA TAF Comments: Low chance for MVFR/IFR stratus and fog overnight. KEWR TAF Comments: Low chance for MVFR/IFR stratus and fog overnight. KTEB TAF Comments: Low chance for MVFR/IFR stratus and fog overnight. KHPN TAF Comments: Timing of IFR conditions overnight could be off by 1-2 hours. KISP TAF Comments: Timing of IFR conditions overnight could be off by 1-2 hours. .OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY... .Saturday-Sunday...Mainly VFR. Isolated to scattered afternoon and evening showers or thunderstorms, mainly north and west of NYC. .Monday...MVFR possible in developing showers. .Tuesday...Mainly MVFR in showers. .Wednesday...Any MVFR conditions improve to VFR.
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&& .MARINE... Light winds will prevail across all waters into the weekend. Swells will however increase, and ocean waters are expected to prevail with seas up to 5 or 6 ft starting Saturday night. Have therefore issued a SCA for hazardous seas starting Saturday night, and this will likely need to be extended in time. Long period swells ahead of tropical cyclone Jose are expected to maintain seas to SCA-levels through the rest of the weekend. Depending on the track and intensity of the system, seas may continue to build further to dangerous levels through at least mid-week, with winds increasing to SCA or possibly gale-force by then. Please continue to monitor NHC forecasts for official information about tropical cyclone Jose. && .HYDROLOGY... No widespread hydrologic impacts are expected through at least this weekend. Any hydrologic impacts from developing tropical cyclone Jose depend largely on forecast track and intensity. Please continue to monitor NHC and WPC forecasts for official information about Jose. www.nhc.noaa.gov www.wpc.ncep.noaa.gov && .TIDES/COASTAL FLOODING... Astronomical tides will rise this weekend into the middle of next week with the approach of a new moon. These rising water levels combined with incoming energetic swells building from Jose, will increase the threat for high surf, dune collision, and localized overwashes along the ocean beachfront Sunday through early next week. Coastal flooding may also become an issue early next week. The magnitude of these threats will depend on the future strength and track of Jose. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory for hazardous seas from 6 PM Saturday to 6 AM EDT Sunday for ANZ350-353-355. && $$ SYNOPSIS...JC/MD NEAR TERM...JC SHORT TERM...JC LONG TERM...MD AVIATION...BC/DS MARINE...JC/MD HYDROLOGY...JC/MD TIDES/COASTAL FLOODING...

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