Area Forecast Discussion
Issued by NWS Upton, NY

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813 FXUS61 KOKX 250233 AFDOKX Area Forecast Discussion National Weather Service New York NY 1033 PM EDT WED AUG 24 2016 .SYNOPSIS... High pressure remains south of the area through Thursday. A weakening front will approach Thursday night. The cold front moves across the area on Friday. High pressure returns this weekend. Another cold front approaches early next week and may linger near the area through Wednesday. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... The forecast is mainly on track. Only made minor adjustments to temperatures and dewpoints for the next few hours to account for the latest trends. Upper ridge remains anchored to our south tonight, as the area remains on the southern edge of the westerlies. Generally clear skies are anticipated. Expect temps tonight to run a little warmer than the past couple of nights as the airmass modifies. Lows will range from around 60, to around 70 in and around NYC. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... Ridge remains anchored to the south Thursday and Thursday night as the area remains on the southern edge of the westerlies. A weak trough approaches from the west. Expect an increase in mid and higher level clouds from the west late in the day, with a good amount of sunshine all day further east. Will cap pops to slight chance, mainly for western sections late in the day. Slight chance pops spread east at night. High resolution models indicate spotty showers moving across the area at night. NWP model solutions output minimal QPF, or keep conditions dry for the most part. High temps will range from around 80 over eastern coastal locations, to the upper 80s in northeast NJ. At night, persistent southerly flow along with plenty of clouds will result in warm temps, with a much smaller range in low temps, upper 60s to middle 70s. There is a moderate risk for rip current development at the ocean beaches Thursday into Thursday evening. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... The latest NWP model suite is in good agreement through this weekend, then they begin to diverge a bit early next week. A strong upper anticyclone will build towards the region Friday and then remain over the Middle Atlantic this weekend. The ridge may begin to shift south and weaken a bit on Monday as a northern stream shortwave traverses across SE Canada. Differences arise with the timing and how much the ridge breaks down. Differences continue through the middle of next week with how much ridging rebuilds aloft. A weak cold front will move through late Friday. Friday will be hot and humid with temperatures surging into the upper 80s and lower 90s. Heat indices will reach the middle 90s and could reach the upper 90s if dew points stay higher than forecast in the afternoon. This is possible if more moisture pools along and ahead of the cold front. However, thermal profiles show potential mixing up to around 850 hPa in the afternoon which should help to lower dew points into the upper 60s in the afternoon. There will be a good amount of dry air in the upper atmosphere as heights actually will rise. Instability is also marginal as there may be a cap around 15kft, so have lowered PoPs to just slight chance. High pressure builds down from SE Canada this weekend with a light northerly flow and slightly cooler air. The most noticeable difference will be less humidity as dew points generally in the lower and middle 60s. This will preclude the need for a heat advisory in NYC since heat indices should only be in the upper 80s this weekend, close to actual air temperatures. Another cold front approaches late Sunday night into Monday. The main shortwave forcing passes well to the north so have mainly kept PoPs at slight chance with chance PoP across the interior. The boundary may then stall near the area Tuesday into Wednesday. This will all be tied to how strong the ridge aloft ends up and if the upper jet stays well to the north leaving the boundary behind. Overall, above normal and humid conditions should continue next week. && .AVIATION /03Z THURSDAY THROUGH MONDAY/...
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High pressure off the northeast coast remains in control into Thursday afternoon. The high moves east Thursday afternoon as a weak trough approaches from the west. VFR through the TAF period. There is a slight chance of showers northwest of the New York City terminals after 20Z. Winds generally SSW less then 10 KTS, to light and variable at outlying terminals overnight. During Thursday morning winds increase and become southerly. Gusts to 18KTS are likely near the coast. .Outlook for 00Z Friday through Monday... .Thursday night-Friday...VFR. A slight chance of showers. Isolated thunderstorms possible Friday. Low chance of MVFR in showers. .Friday night-Monday...VFR.
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&& .MARINE... High pressure remains offshore, and southerly wind flow will prevail tonight through Thursday night. Speeds increase late in the day Thursday, and winds over the ocean waters may approach SCA criteria, or frequent gusts to 25 kt. Not enough confidence in this actually occurring, so no plans to issue a SCA at this time. Seas build to 4 feet across the ocean waters late in the day and into Thursday night. Guidance suggests 5 Footers are not out of the question. If that becomes more clear, later shifts may consider issuance of a SCA due to the borderline winds and seas. For non ocean waters, seas/waves should remain 2 ft or less. There remains the potential for a tropical swell on the waters late this weekend and early next week. Seas could build to around 5 ft with this long period SE swell. Winds and seas should fall below SCA levels through the first half of the weekend. Then SCA for hazardous seas is possible on the ocean Sunday into Monday as seas build close to 5 ft due to a long period SE swell. && .HYDROLOGY... No significant widespread precipitation is expected into next week. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...DS/PW NEAR TERM...JC/PW SHORT TERM...PW LONG TERM...DS AVIATION...MET MARINE...JC/DS/PW HYDROLOGY...DS/PW is the U.S. government's official web portal to all federal, state and local government web resources and services.