Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 201145 AFDOKX Area Forecast Discussion National Weather Service New York NY 745 AM EDT Sun Aug 20 2017 .SYNOPSIS... High pressure will build into the region today, and then settle to the south and east Monday through Tuesday. A frontal system approaches Tuesday Night and crosses the region Wednesday. Canadian High pressure then builds in through Saturday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Vigorous shortwave continues to pivot northeast of the region this morning with associated cold front continuing to push well offshore. In its wake, zonal upper flow develops with high pressure building in from the west. Deep NW flow and subsidence will result in a 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 risk for rip current development for E LI beaches due to lingering 3 ft @ 6-7 sec swells.
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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 /12Z SUNDAY THROUGH THURSDAY/...
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High pressure will build in for much of the TAF period, moving offshore late in the period. VFR through the TAF period. A westerly flow will dominate during the TAF period. W-NW flow 10kt gusting between 15 and 20 kt today will subside tonight into Monday with winds decreasing to less than 10 kt. Coastal terminals, particularly KJFK could become more SW than forecast late today. Chances of a true sea breeze that will be directly onshore are 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... Sub-SCA conditions expected through Tuesday afternoon as high pressure traverses southeast through the waters. Winds and seas will increase ahead of a cold frontal Tuesday into Tuesday Night. Marginal SCA gusts possible Tue Aft/Tue night with ocean seas building to SCA levels Tue Night/Wed. In the wake of the front, winds and seas are expected to fall below SCA levels for late week as high pressure slowly builds towards the area. && .HYDROLOGY... Dry conditions through Monday. Hydrologic impacts from potential showers and thunderstorms Tuesday into Wednesday are uncertain at this point. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...NV NEAR TERM...NV SHORT TERM...NV LONG TERM...Maloit/NV AVIATION...JM MARINE...NV HYDROLOGY...NV is the U.S. government's official web portal to all federal, state and local government web resources and services.