Area Forecast Discussion
Issued by NWS Upton, NY

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132 FXUS61 KOKX 270527 AFDOKX Area Forecast Discussion National Weather Service New York NY 127 AM EDT WED JUL 27 2016 .SYNOPSIS... A weak cold front will continue pushing south of Long Island overnight. High pressure will then build from the west going into Wednesday, and move east by Thursday. A weak cold front will approach the region Thursday Night, and remain in the vicinity as a few waves of low pressure pass nearby into the weekend. High pressure builds back in for early next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Forecast database slightly adjusted to better match observed trends. Added some more cloud coverage over the next few hours. Shield of cirrus looks to exit region during the overnight. A weak cold front will continue pushing south of Long Island overnight. The northerly flow will continue and remain light. The clouds will decrease later tonight with weak high pressure starting to build in. Sided with the cool end of guidance for lows tonight, with a wide range of temps, from the 70s invof NYC, to the 60s most elsewhere, to some upper 50s in some interior valleys. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... Models continue to agree on the region lying between a closed low over Quebec and flat SE US ridging, with zonal flow aloft. At the surface, high pressure will give way to weak thermal troughing developing in the afternoon. Hot conditions will continue, with highs 90-95, near or slightly above the warmest MOS guidance. Dewpoints in the upper 50s and lower 60s will keep heat index values at or just below ambient temperatures, so do not plan to extend the heat advisory for NYC. Temps Wed night will be similar to those forecast for tonight, will perhaps a little more widespread upper 50s across the interior. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Models are in general agreement with the H5 pattern across North America through the long term. A cutoff low over Northern Quebec Thu morning will be slow to move NE through Friday keeping a broad trough across the NE quarter of the US. As the cutoff lifts into the Maritimes heights will slowly begin to rise as a deep anticyclone reestablishes itself over the Central US. Somewhat of a complex scenario at the sfc during the first half of the period. A cold front approaches from the west as a wave of low pressure ejects out of the mid-Mississippi valley Thu/Thu night. 12z NWP guidance have come into better agreement that this low will impact the area on Fri into Fri night. However...there are still differences with timing...track and strength that need to be resolved. Have increased pops to likely on Fri since there is better agreement amongst the guidance. Instability not very impressive...although there could be some rumbles of thunder. There is also the potential for locally heavy rain with PW`s forecasted to be in excess of 2 inches. Once the wave moves by there should be a lull on Sat although with the front remaining close to the area have kept schc pops. Another wave may impact the area Sat night into Sun...although the long range models diverge at this point. Have kept low chc pops for now...but it could end up being mostly dry if the wave doesn`t materialize. The boundary is finally nudged southward early next week as high pressure builds in from Canada. One final day with 90 degree temps Thu...then highs will be closer to normal levels into early next week. && .AVIATION /06Z 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...expected at KLGA/KHPN by late afternoon...with moderate potential of se sea breeze at KEWR/KTEB in late afternoon. Winds diminish to light s/sw flow .OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY... .Late tonight-Thursday...VFR. Isolated showers and thunderstorms possible Thursday afternoon, mainly NW of the NYC terminals. .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 Wed night. There is a low chance of SCA conds on the waters Fri depending on the track and strength of low pressure passing near the area. Otherwise...sub-advsy conds are expected through the rest of the period. && .HYDROLOGY... There is potential for significant rainfall from late Thursday night into Friday night. Locally heavy rainfall is possible...which may cause flooding concerns although it is still too early for specifics. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...Goodman/24 NEAR TERM...Goodman/JM SHORT TERM...Goodman LONG TERM...24 AVIATION...NV MARINE...Goodman/24 HYDROLOGY...Goodman/24

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