Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 131338 AFDOKX Area Forecast Discussion National Weather Service New York NY 938 AM EDT Sun Aug 13 2017 .SYNOPSIS... High pressure builds in today and shifts offshore on Monday. Weak low pressure passes to the south Monday night. A cold front then approaches from the north Tuesday before sliding to the south Tuesday night. Weak high pressure will then be in place for Wednesday. A series of fronts may impact the late week period. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Minor updates made to reflect current trends. Have adjusted wind speeds upward based on this morning`s observations. As the front continues eastward the pressure gradient should gradually relax through the afternoon, allowing any stronger speeds and gusts to subside. Surface high pressure builds in today and the flow aloft becomes more zonal. Mostly sunny, and with forecast 850mb temps around 14C plus a downslope flow for most spots, went closer to the warmest guidance for high temperatures. 3 to 4 ft @ 8 sec period southerly swells will result in a moderate rip current risk for the NYC and Western LI ocean beaches, and a high risk for Eastern Long Island ocean beaches today.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... High pressure center shifts towards the forecast area tonight with mostly clear conditions and light to calm winds. This setup will allow for good radiational cooling away from the city. Lows in some of the outlying suburbs will be in the mid to upper 50s. High pressure shifts offshore for Monday and it looks like another mostly sunny day. Winds will become onshore, but on the light side. This will probably result in slightly cooler highs for some coastal spots as compared to today, but inland spots should reach or slightly exceed today`s highs with 850mb temps at 14-15C. A weak low pressure wave then passes us to the south Monday night. The rain shield should be too far south of us, so will continue with a dry forecast through the night. && .LONG TERM /TUESDAY THROUGH SATURDAY/... A shortwave approaches the Northeast on Tuesday, and this will help push a weak cold front towards us. The front could reach the Lower Hudson Valley by day`s end, and this is where the best overall lift will be. Will therefore go with isolated afternoon and early evening showers/TSTMs here. The rest of the tri state area should remain dry. With 850mb temps 15-16C, highs 85-90 for most spots. A relatively weak northern stream ridge builds into the area Tuesday night-Wednesday night, so it should be dry then. Zonal flow then sets up over the area Thursday-Saturday, with the models differing on the timing of shortwave troughs and ridges embedded in the flow. The result should be a period of unsettled weather, that will probably end up more dry than wet for most people, depending on exactly where a surface frontal boundary ends up stalling out relative to the region. For now bring in slight chance pops to mainly western areas late Thursday, then chance pops throughout Thursday night-Saturday. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... A cold front will pass off the Long Island coast this mrng. Rapid improvement to vfr thru 13Z with developing nw winds. The nw flow will continue into this eve before veering to the n late then to the se after 12Z Mon. There is a low potential that a sea breeze develops today along the immediate s coasts. This would bring winds at KJFK to 180 around 17-19Z. .OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY... .Monday...VFR. .Tuesday...VFR. Low and sparse potential for showers and tstms NW of NY/NJ metro in the afternoon. .Tuesday night-Thursday...VFR. && .MARINE... Seas will build to around 5 ft on the ern ocean today. The sca has therefore been continued. Elsewhere, winds and seas will remain blw sca lvls, so the advy was cancelled for anz355. Seas will subside overnight, then winds and seas will remain blw sca lvls on all waters Mon-Fri. && .HYDROLOGY... No hydrologic impacts are expected through Saturday. && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None. NY...High Rip Current Risk until 8 PM EDT this evening for NYZ081. NJ...None. MARINE...Small Craft Advisory for hazardous seas until 2 AM EDT Monday for ANZ350-353.
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&& $$ SYNOPSIS...JC NEAR TERM...JC/MD SHORT TERM...JC LONG TERM...JC/Maloit AVIATION...JMC MARINE...JMC/Maloit HYDROLOGY...JC/Maloit

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