Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 290542 AFDOKX Area Forecast Discussion National Weather Service New York NY 142 AM EDT MON AUG 29 2016 .SYNOPSIS... High pressure along the New England and Mid Atlantic coasts will move east tonight, while a cold front approaches from the Great Lakes. The front will work slowly across Monday, then high pressure will build in Monday night into Tuesday. The high will give way to a cold front late Wednesday into Wednesday night, followed by high pressure for the end of the week and into next weekend. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Forecast is on track, only minor changes made to reflect current observations. High amplitude ridge centered across the Mid Atlantic and nearby atlantic will flatten as an upper trough moves across southern Canada overnight and into New England on Monday. This will allow a cold front to approach. Model guidance looks too aggressive with high and mid level cloud cover overnight, and have trimmed back through this evening, with mostly clear skies expected until after midnight when deeper low level moisture starts to arrive. Even then, forcing looks weak with the main troughing only just entering northern New England by 12Z Mon, so only bring in mostly cloudy skies and slight chance for a shower late tonight NW of NYC and across southern CT. Low temps per MOS guidance blend will be in the lower 70s in NYC, and in the 60s elsewhere. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... Cold front will move slowly across Monday morning, with morning clouds then will likely get hung up right along the coast until late afternoon. Post-frontal downslope WNW flow will clear skies out during the late morning and afternoon and allow temps to be quite warm throughout, with lower 90s in many places all the way down to the coast, a little higher than the warmest of the GFS/NAM MOS guidance. The air mass will remain relatively dry, so heat index values will be close to actual air temps. High pressure will build in from the NW Monday night, with mostly clear skies. Lows Mon night will range from the lower 70s in NYC, to the 60s most elsewhere, to 55-60 in the interior valleys and the Long Island Pine Barrens. There is a moderate risk for rip current development across the ocean beaches of Nassau, Queens and Brooklyn, and a high risk for rip current development across Suffolk ocean beaches as long period SE swells from distant tropical cyclone Gaston build to 3 to 4 ft. Breaking surf in the 3-5 ft range could occur as well. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... As ridge resides well to the west, upper trough approaches the northeast Wednesday and Thursday, with its axis passing east by Friday. Ridging then builds behind it. Surface high pressure early in the period will give way to approaching cold front Wednesday night. This front moves east Thursday as high pressure builds behind providing plenty of sunshine and dry weather through the weekend. A dry period is expected, with best chance for rain occurring along and ahead of the front late Wednesday-Wednesday night and into Thursday. Due to ample support aloft, and consistent model output of precip, feel scattered activity looks like a good bet mainly Wednesday night. Seasonable or slightly above seasonable temperatures Tuesday will warm ahead of the front Wednesday, averaging at least 5 degrees above normal. Then temperatures settle back closer to or just below seasonal norms behind the front late this week. Some moderating in temps likely next weekend. The threat for rough surf and high risk for rip current development should continue through the mid to late week due to SE swells from distant Hurricane Gaston. && .AVIATION /06Z MONDAY THROUGH FRIDAY/...
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VFR. A weak cold front approaches overnight and slowly moves through the region today. High pressure builds in behind the front tonight. winds southwest to west 10 KTS or less until the frontal passage with winds gradually shifting to the west then northwest. at times the winds may be around 310 true as the front goes through. In the northwest flow gusts up to 18 KTS will be possible at the NYC metro terminals, however, gusts may be less frequent than indicated in the TAFs. There is a low chance that a sea breeze may move into KJFK or remain just south of the terminal after 17Z. .Outlook for 06Z Tuesday through Friday... .Monday night-Wednesday Afternoon...VFR. .Wednesday Night-Thursday Morning...Showers/tstms possible with MVFR conditions. .Thursday Afternoon-Friday...VFR.
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&& .MARINE... Ocean seas will continue to slowly build in response to long period swells generated by distant Hurricane Gaston. There is a low chance that the combination of wind waves generated by 15-kt WSW flow and these incoming swells could bring ocean seas up to 5 ft on Monday, but since NWPS guidance has tended to run high with seas, capped max seas at 4 ft through Monday night, which is in agreement with Hurricane WaveWatch guidance. From Tuesday through Thursday, and possibly into Friday, ocean seas will remain elevated due to long period swells generated by Gaston. The non-ocean waters should remain rather tranquil, although it could get a little rough as some of the ocean swells make it into the extreme eastern portion of Long Island Sound and western Block Island Sound. Winds should remain below SCA criteria, although they will increase on Wednesday ahead of an approaching weak cold front. Gusts on a northerly wind flow are also anticipated as the waters sit between the departing front, and high pressure building late Thursday and Thursday night. && .HYDROLOGY... No significant widespread precipitation is expected. && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None. NY...High Rip Current Risk from 6 AM EDT this morning through this evening for NYZ080-081. NJ...None. MARINE...None.
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&& $$ SYNOPSIS...Goodman/PW NEAR TERM...Goodman/JP/PW SHORT TERM...Goodman LONG TERM...PW AVIATION...MET MARINE...Goodman/PW HYDROLOGY...Goodman/PW

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