Area Forecast Discussion
Issued by NWS Upton, NY

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583 FXUS61 KOKX 270827 AFDOKX Area Forecast Discussion National Weather Service New York NY 427 AM EDT WED JUL 27 2016 .SYNOPSIS... Weak high pressure will remain through tonight, then weaken on Thursday. A weak cold front will approach Thursday night, and remain nearby into the weekend as a few waves of low pressure pass nearby. High pressure will return early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Expect sunny skies to start, then high clouds mainly this afternoon as a mid level shortwave approaches in zonal flow aloft. High temps should be a shade hotter this afternoon than those of yesterday inland, still mostly lower 90s, while coastal sea breezes cap temps in the upper 80s along the south shore of Long Island and SE CT. Heat indices should be close to ambient temps for the most part via lower dewpoints in the lower 60s, but afternoon sea breezes bringing in more humid marine air with dewpoints in the upper 60s could boost heat indices right along the coast to just above ambient temps. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Expect mostly clear skies tonight as the aforementioned shortwave passes by. GFS tries to produce some light precip in association with this wave, but this does not look realistic as the air mass in place should still be fairly dry and stable. Low temps will be close to or slightly warmer than those expected for early this morning, in the 70s invof NYC and across western Long Island, and in the 60s elsewhere. Thu looks like another hot and increasingly humid day, with high temps in the lower 90s for NYC metro and inland sections, and upper 80s near south facing shores. Dewpoints increasing to the upper 60s to near 70 from NYC metro east should push heat index values into the mid/upper 90s in those areas, with lower 90s elsewhere. Zonal flow aloft turns a little more SW through the day on Thu, and the combo of an approaching mid level shortwave and convergence invof a weak inland thermal trough and along sea breeze boundaries should spark at least isold convection. The 00Z SBU NAM/GFS WRF and the NCAR ensemble are all signaling more focused development along the sea breeze in NYC metro and across Long Island where greater instability will also reside, as increasing dewpoints push MLCAPE to 1000-1500 J/kg across Long Island and 500-1000 J/kg most elsewhere, so have scattered PoP for those areas in the afternoon. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... A low pressure system will move from the Mid-Atlantic northeastward Thursday night into Friday night, resulting in showers and thunderstorms across the area. There is the potential for locally heavy rainfall with precipitable water values in excess of 2 inches. As the wave of low pressure departs, there may be a break in the precipitation Saturday, but isolated to widely scattered showers cannot be ruled out. More unsettled conditions are possible Saturday night into Sunday, as another potential short wave moves through. Will continue mention of chance pops due to model differences at this time. High pressure builds in from Canada early next week. Temperatures look to be near seasonable levels Friday into early next week. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... High pressure builds in from the west today and then east tonight. VFR through the period. Light northerly winds back to the W/WSW in the late morning/early afternoon...except likely holding ne at KLGA. Southerly sea breeze development expected at coastal terminals in early afternoon...at KLGA/KHPN by late afternoon...with moderate potential of SE sea breeze at KEWR/KTEB in the late afternoon. Winds diminish to light S/SW flow tonight. .OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY... .Late Tonight...VFR. .Thursday...Mainly VFR. Isolated/sct showers/tstms possible in the afternoon. .Thursday Night-Sunday...MVFR or lower possible with a chance of showers and thunderstorms. The best chance looks to be on Friday. && .MARINE... Sub-SCA conditions will prevail through the weekend. && .HYDROLOGY... There is potential for significant rainfall from late Thursday night into Friday night. Locally heavy rainfall is possible, which could cause flooding. It is still too early for specifics. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...FIG/Goodman NEAR TERM...Goodman SHORT TERM...Goodman LONG TERM...FIG AVIATION...NV MARINE...FIG/Goodman HYDROLOGY...FIG/Goodman

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