Area Forecast Discussion
Issued by NWS Upton, NY

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132 FXUS61 KOKX 271816 AFDOKX Area Forecast Discussion National Weather Service New York NY 216 PM 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/... Made some minor adjustments to temps and dewpoints to reflect current observations. Otherwise, expect mostly sunny skies with few to scattered cu. Then high clouds move in 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 /18Z WEDNESDAY THROUGH MONDAY/...
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VFR with a weak S/SW flow through Thursday with local seabreeze enhancements. Latest radar data and surface observations show seabreeze just south of KLGA and southeast of KEWR. Expect seabreeze to move through both locations with the next 1-2 hours. The W/SW flow could hold on longer at KEWR by 1-2 hours. Should propagate as far north as kHPN by late afternoon. There is a low probability of MVFR/IFR cigs late tonight at the coastal terminals. Preference at this time is to remain VFR. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/www.weather.gov/zny/n90 KJFK TAF Comments: No unscheduled amendments expected. KLGA TAF Comments:High probability in southerly seabreeze developing in the next 1-2 hours. KEWR TAF Comments: Moderate probability of SE seabreeze this afternoon, with most likely timing of onset between 19z and 21z. Seabreeze may waver near the airport for a few hours this afternoon, before passing through. KTEB TAF Comments: Moderate probability of SSE seabreeze this afternoon...with most likely timing of onset between 20z and 22z. Sea breeze may waver near the airport for a few hours this afternoon, before passing through. KHPN TAF Comments: Moderate to high probability of seabreeze by late afternoon, from 20Z to 22Z. KISP TAF Comments: No unscheduled amendments expected. .OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY... .Thursday Afternoon...VFR. Isolated showers and thunderstorms possible, mainly NW of the NYC terminals. .Thursday Night into Friday Night...MVFR or lower possible in showers and thunderstorms, possibly widespread. Patchy fog. .Saturday...VFR. .Saturday Night into Monday...Iso-Sct diurnal shra/tsra possible.
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&& .MARINE... Sub-SCA conditions will prevail through the weekend. High pressure builds, then gives way to waves of low pressure late this week and 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/PW SHORT TERM...Goodman LONG TERM...FIG AVIATION...DW MARINE...FIG/Goodman/PW HYDROLOGY...FIG/Goodman

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