Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 232151 AFDOKX Area Forecast Discussion National Weather Service New York NY 551 PM EDT TUE AUG 23 2016 .SYNOPSIS... High pressure over the region will slide offshore through Thursday. A cold front will slowly approach from late Thursday into Friday, and move across Friday evening. High pressure will follow for the weekend. Another frontal system will approach on Monday. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... High pressure will remain overhead through Wednesday morning. This will result in clear skies overnight, although continued southerly flow will allow dewpoints to slowly increase, resulting in less than ideal conditions for radiational cooling and overnight lows that are 5-10 degrees warmer than last night. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
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High pressure begins to slowly shift offshore during the day on Wednesday. This will allow for increased southerly flow along with slightly higher temperatures and dewpoints. High clouds will then begin to increase overnight Wednesday night as the ridge flattens ahead of an approaching cold front. There is a moderate risk for meteorological enhancement of rip current formation at Atlantic Beaches on Wednesday.
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&& .LONG TERM /THURSDAY THROUGH TUESDAY/... Operational and ensemble models are in good agreement for the long term, especially with the passage of the cold front on Friday. In the mid and upper levels, a weak upper level trough moves through on Thursday. This trough looks stronger to the north of the area. At the surface, high pressure will be situated off the East Coast. This will pump in a warm and humid air mass, out ahead of an approaching cold front. Surface low pressure over southeastern Canada will trek east-northeast with its associated cold front approaching the area Thursday night. A pre-frontal surface trough should impact the area late Thursday night, mainly for areas north and west of New York City. Any precipitation should hold off until this trough moves over the area. So will push back slight chance POPs late Thursday time frame. Upper level flow looks to be rather zonal Thursday night into Friday, so would expect the cold front to be rather progressive, moving through late in the day Friday/early Friday night. However, not much in the way of moisture for this front to tap into, so much of the area could remain dry as the cold front moves through. some surface based CAPE will allow an isolated thunderstorm to develop. High pressure builds in behind the front for the weekend. Upper level ridging for late Saturday into Sunday, with another surface cold front approaching Sunday night. There is some uncertainty with the passage of this cold front. 12Z GFS is more progressive than the 00Z ECMWF and pushes the front through late Monday night with high pressure building in for Tuesday. The ECMWF stalls the front just to our south, with disturbances tracking along the boundary. As far as temperatures are concerned, seasonably warm for Thursday with temperatures in the lower to middle 80s, warmer for Friday under warm advection, with lower 90s possible in the New York City metro area. Not as warm for Saturday, but still above normal for this time of year. Thereafter, slightly cooler, but still above normal temperatures for the rest of the long term. Humidity levels will increase Thursday into Thursday night, with dew points in the lower 70s by Friday. Heat index values could approach the middle to upper 90s for the metro area on Friday, but this will only be for one day as the cold front ushers in a cooler and slightly less humid air mass for the remainder of the long term. Heat index of 100 in the metro area looks unlikely at this time. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/...
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High pressure slowly slides offshore into Wednesday. VFR through the TAF period. Seabreeze through CT terminals and KJFK/KISP. No looks like unlikely to move into KLGA/KHPN and will not move into KEWR/KTEB. Have removed seabreeze from TAF at all 4 locations. Winds become light and variable throughout this evening, with seabreezes impacting all terminals but KSWF late Wednesday morning/early Wednesday afternoon. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/ KJFK TAF Comments: Gusts to 15-20kt likely trough 00z, with isolated gusts possibly lingering to 01-02z. KLGA TAF Comments: Very low chance of seabreeze passage through 01z. KEWR TAF Comments: Isolated gusts to 15-20kt possible through 00z. Wind direction could vary from 250 true/260 magnetic to 290T/300M until become light and variable. KTEB TAF Comments: No unscheduled amendments are expected. KHPN TAF Comments: No unscheduled amendments are expected. KISP TAF Comments: Isolated gusts to 15-20kt possible through 00z. .Outlook for 18Z Wednesday through Sunday... .Wednesday-Wednesday night...VFR. Afternoon seabreezes expected. .Thursday-Thursday night...Mainly VFR. Slight chance of afternoon/nighttime showers and thunderstorms, with brief MVFR conditions possible. Best chances North and West of NYC. .Friday...Mainly VFR. Slight chance of afternoon showers and thunderstorms, with brief MVFR conditions possible. .Friday night-Sunday...VFR.
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&& .MARINE... Winds and seas should remain below SCA criteria into early next week. There is still a small to medium chance that ocean seas and wind gusts could reach SCA criteria some time Thu night into Fri ahead of a cold frontal passage. There is also a suggestion of tropical swell encroaching on the waters by Sunday, with waves building to 5+ ft late in the long term period. && .HYDROLOGY... No significant widespread precipitation is expected through the period. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...FEB/MET/JP NEAR TERM...FEB/MET SHORT TERM...FEB/MET LONG TERM...JP AVIATION...Maloit MARINE...FEB/MET/JP HYDROLOGY...FEB/MET/JP is the U.S. government's official web portal to all federal, state and local government web resources and services.