Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 201522 AFDOKX Area Forecast Discussion National Weather Service New York NY 1122 AM EDT Sun Aug 20 2017 .SYNOPSIS...
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High pressure building into the region today, will settle to the south and east Monday through Tuesday. A frontal system will approach Tuesday night, and move across on region Wednesday. Canadian high pressure will then build in through Saturday.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Deep NW flow and subsidence with building high pressure in the wake of a departing upper trough will result in a mostly sunny, comfortably dry, and seasonably warm day today. Highs generally in the lower to mid 80s. Late day sea breeze possible along the immediate south coasts. There is a moderate rip current risk for the beaches of eastern Long Island.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... Zonal upper flow continues into Mon, and then begins to back a bit Tuesday ahead of a longwave trough digging into the Great Lakes. At the surface...high pressure gradually translates to the south and southeast tonight into Monday morning. Good radiational cooling conds tonight, with lows in the 50s across far outlying areas. 60s to around 70 elsewhere. As the high builds south and east, heat and humidity will build into the region Monday into Tuesday. Highs will generally be well into the 80s to around 90 on Monday, and upper 80s to lower 90s for Tuesday. Low prob of heat advisory for portions of the NYC/NJ metro on Tuesday as humidity levels climb. Models are indicating potential for isolated diurnal convection (along sea breeze boundary or hills) on Tuesday as instability increases and convectively induced vort energy rotates around the upper ridge. Low predictability on convective details at this point. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Longwave trough digs into the Great Lakes Tue into Tue Night and then slides into the NE US for the mid to late week. An associated frontal system interacting with a sub-tropical airmass will bring the next chance for organized shower and tstm activity Tue Night into Wed. Low predictability on the convective details at this point...contingent on timing of front/forcing with diurnal instability. Then a significant cool down expected for the end of the week as the long wave trough settles into the NE US, and Canadian high pressure slowly builds SE from Central Canada through the midweek. This will provide mostly sunny, dry and unseasonably cool conditions to end the week into the weekend. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/...
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High pressure will builds to the south into Tuesday morning. VFR through the TAF period. NW winds back to the WNW this afternoon with gusts 15-20KT at most terminals. Gusts abate by early evening, with winds becoming light and variable throughout by around midnight. Coastal terminals, particularly KJFK could go 20-30 degrees farther S than forecast late today. Chances of a true sea breeze are very low. .OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY... .Monday-Tuesday Morning...VFR. SW gusts to near 20kt Monday late afternoon to early evening with sea breeze enhancement. .Tuesday Afternoon-Wednesday...A chance of showers and thunderstorms with MVFR or lower conditions possible. SW gusts 20-25kt Tuesday afternoon through Tuesday night. .Wednesday Night-Thursday...VFR.
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&& .MARINE...
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Quiet through Tuesday afternoon as high pressure moves across. Winds and seas ahead of a cold front Tuesday into Tuesday night could bring some 25-kt gusts in the afternoon/evening, with ocean seas building to 5-7 ft Tue night-Wed. In the wake of the front, winds and seas should quiet down for late week as high pressure slowly builds.
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&& .HYDROLOGY...
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Dry through Monday. Then impacts from potential showers and thunderstorms Tuesday into Wednesday are still uncertain.
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&& .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...NV NEAR TERM...Goodman/NV SHORT TERM...NV LONG TERM...Maloit/NV AVIATION...Maloit/JM MARINE...NV HYDROLOGY...NV

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