Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 222229 AFDOKX Area Forecast Discussion National Weather Service New York NY 629 PM EDT Tue May 22 2018 .SYNOPSIS... A warm front will approach this evening as a wave of low pressure ripples east along it. A weak cool front will follow late tonight. High pressure will return thereafter and remain through Saturday. Another frontal system will impact the area early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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Initial batch of light rain is moving offshore leaving behind scattered showers for the rest of the evening. PoPs have been lowered after 00z as there does not appear to be any widespread showers upstream and do not anticipate any new development other than scattered showers at any time. A wave of low pressure on the warm front to the south should initially help keep the warm front south, but it may still sneak in from the west later tonight as this wave passes east, just ahead of a weak cold front. This 2nd front should bring additional showers, possibly an isolated elevated thunderstorm with elevated instability after midnight. The light pressure gradient overnight after the surface wave passes should also promote development of patchy fog. Low temps tonight 55-60 per MOS blend.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... A drying NW flow should develop on Wed, with skies becoming mostly sunny. Expect a warm day, with downslope flow and deeper mixing than model forecasts yielding high temps above MOS, with lower/mid 80s. Temps Wed night under clear skies may drop to near 50 well inland with lighter winds and better radiational cooling there, but remaining in the lower 60s in and around NYC. && .LONG TERM /THURSDAY THROUGH TUESDAY/... The center of high pressure passes through the region on Thursday with plenty of sunshine and high temperatures above normal. The dry weather continues on Friday with the high offshore. It`ll be a warmer and more humid day for most with SW winds. Highs in the upper 70s to mid 80s for most spots. The weather pattern is still somewhat unclear for the upcoming holiday weekend. Models at least seem to agree that at some point a cold front drops down from the north and eventually sinks south of the tri-state area. Differences in the timing of the frontal passage still exist among the models and ensembles. For Saturday, prefer slower timing of the cold front approach given that all global models show a 500mb ridge over the region. This in turn would allow for temps to rise to around 90 for parts of the city and NE NJ as well as perhaps a few spots in the Lower Hudson Valley. 80s expected elsewhere away from the immediate coast. Will go with only a slight chance of TSTMs north and west of the city during the afternoon. The cold front then moves into the area at some point Sunday night and perhaps remains nearby through the day before sinking farther to our south during Monday. Will go with chc PoPs Sunday through Monday with clouds outweighing sunshine. Sunday`s highs might need to be lowered further than the current forecast, especially if models don`t trend towards a slower frontal passage. Have somewhat higher confidence in Monday`s highs, which will be below normal with an easterly flow. A wave of low pressure forms along the front to our south, but models indicate that the low shifts to the east during Tuesday with minimal impact over us. There still could be a cold front moving through, so will go with slight chc PoPs for the time being. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/... A warm front slowly approaches from the southwest through this afternoon. The warm front lifts into the region this evening with a cold front moving across late tonight into early Wednesday. Expect gradually lowering ceilings and rain showers moving in from west to east going into late this afternoon. A mix of MVFR to VFR conditions will become all MVFR into late this afternoon as rain showers become more widespread. IFR develops tonight with locally sub-IFR conditions at times. An isolated thunderstorm is possible tonight. Gradual improvement in conditions expected from west to east Wednesday morning. S-SE winds 5-10 kt will become more easterly and decrease in speed late this afternoon into tonight. Some variability in direction is expected overnight before a more NW flow of 5-10 kt develops into early Wednesday. ...NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component fcsts, can be found at: http:/www.weather.gov/zny/n90 KJFK TAF Comments: Variable wind direction between around 100-200 degrees before 22Z. MVFR/IFR timing could be 2-4 hrs off from forecast. KLGA TAF Comments: MVFR/IFR timing could be 2-4 hrs off from forecast. KEWR TAF Comments: Nearly calm winds before 21Z with variable direction between around 100-200 degrees. IFR timing could be 2-4 hrs off from forecast. KTEB TAF Comments: MVFR/IFR timing could be 2-4 hrs off from forecast. KHPN TAF Comments: Category could fluctuate between MVFR and IFR before 22Z. KISP TAF Comments: Nearly calm winds before 21Z with variable direction between around 100-200 degrees. MVFR/IFR timing could be 2- 4 hrs off from forecast. .OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY... .Wednesday afternoon-Thursday...VFR. .Friday...VFR. SW winds 10-15 kt with gusts up to 20 kt through early evening. .Saturday...Mainly VFR. Isolated thunderstorms possible N and W of the metro terminals starting in the afternoon with possible MVFR. .Sunday...MVFR or lower at times with a chance of showers and thunderstorms. Otherwise VFR. && .MARINE...
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A warm front over the waters may bring some fog overnight, but should stay above 1 nm. Otherwise, a weak pressure gradient over the waters through Thursday will promote tranquil conditions. There is a low chance for SCA conditions for Friday into Saturday, with gusts close to 25 kt and ocean seas close to 5 ft.
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&& .HYDROLOGY...
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A heavy downpour is possible tonight with any showers that develop, but no hydrologic impacts are anticipated. No significant hydrologic impacts expected through the week.
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&& .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...Goodman NEAR TERM...Goodman/DS SHORT TERM...Goodman LONG TERM...JC AVIATION...JM MARINE...JC/Goodman HYDROLOGY...JC/Goodman

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