Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 200650 AFDOKX Area Forecast Discussion National Weather Service New York NY 250 AM EDT Sat May 20 2017 .SYNOPSIS... High pressure builds in through Saturday night, moving offshore on Sunday. A series of frontal systems impact the area next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Updates for more cloud cover based on trends, satellite imagery. A few showers are possible, particularly for western zones toward morning based on upstream shower activity, and latest high resolution progs. Surface high pressure, centered over the Ontario/Quebec border was building into the region. Gusty north winds were occurring with the initial cold advection and drier air. Updated temperatures and dew points for hourly trends with the cooler and drier air moving into the area. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/... High pressure will be over the region Saturday and Saturday night with a cooler and drier air mass across the region. A spot shower is possible in the morning, especially western zones. Temperatures will return to more seasonable levels Saturday. Dry weather expected Sunday. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Upper ridge axis passes to the east at the onset of the period with a broad upper trough over the mid section of the country translating slowly east through the week. This will result in multiple frontal systems impacting the area this week, the first Monday into Monday night, and then another Wednesday night into Thursday. Both have the potential for widespread showers/isolated thunderstorms and rainfall amounts in excess of an inch. Global models, in particular the GFS and ECMWF, are in overall good agreement with a gradual eastward translation of a high amplified flow across the conus. There are of course some timing differences, but they are not that significant for this point in time. Temperatures Sunday into Monday will be several degrees below seasonable, in particular Monday, with onshore flow and widespread rain. The rest of the week will moderate to near or slightly above seasonable levels. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
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VFR as high pressure builds through tonight. NE flow 10-15 kt through the remainder of the night. Frq gusts at NYC terminals expected as well...occasional elsewhere Gusts expected to diminish around 15z as pressure gradient relaxes as high pres builds from the north. Hi res models are indicating the potential for the showers over western PA to impact NYC terminals between 15z and 20z. Have been waiting to see how this unfolds...and for more of the guidance to be in agreement before adding to TAFs. May add into 09z amendments. Intensity will be light. Winds continue to veer to the NE Saturday morning and then to the E and SE in the afternoon while decreasing in speed. Winds at KJFK/KISP/KBDR/KGON could be 10-20 degrees more to the south AFT 18Z...if seabreeze develops. Land/sea temp/density differential may not be enough though. .OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY... .SATURDAY NIGHT AND SUNDAY...VFR. .SUNDAY NIGHT-MONDAY...MVFR or lower conditions in showers. Slight chance of thunderstorms on Monday. .TUESDAY...VFR. .WEDNESDAY...Mainly VFR, chance of late day showers, slight chance of thunderstorms.
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&& .MARINE... Winds were shifting to the north with the passage of a cold front, and will be briefly gusty, with winds and seas below small craft levels. Brief 25 kt gusts are possible this morning. Below small craft advisory level conditions expected across area waters through tonight as high pressure builds across the area. Sub advisory conditions expected Sunday as high pressure builds over the waters, then passes east. Increasing southerly flow is expected Monday ahead of a cold front. Conditions may approach SCA criteria as winds increase, and ocean seas build to 4 or 5 ft. Then, expect winds to diminish and seas to remains fairly tranquil, or subside somewhat as high pressure builds across the waters Tuesday into Wednesday. && .HYDROLOGY... No hydrologic impacts are expected at this time. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$

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