Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 170540 AFDOKX Area Forecast Discussion National Weather Service New York NY 140 AM EDT Sun Jun 17 2018 .SYNOPSIS...
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High pressure will remain centered to our south through Sunday night. A cold front approaches from the northwest on Monday and passes through Tuesday morning. The front will remain to the south of the area through the rest of the week with high pressure over the region.
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&& .NEAR TERM /UNTIL 6 AM THIS MORNING/... High clouds continue to push south of the area with clearing expected through midnight. Otherwise, high pressure will build across the area tonight with low temperatures ranging from near 70 in midtown NYC, to the mid 50s in the Long Island Pine Barrens and the interior valleys north/west of NYC. A MAV/MET/ECS blend was used for overnight lows. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/... Deep-layered ridging keeps us dry Sunday and Sunday night with cirrus as the primary cloud type. Even with the cirrus, inland areas should see high temperatures range from the middle 80s to near 90s. Southerly flow will keep temperatures right along the coast in the lower 80s. It`ll begin to feel a little more humid, but dewpoints will be mainly in the 50s - still not high enough to make it feel warmer than the actual temperature. A MAV/MET/ECS blend was used for Short term temperatures. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... At the start of the period, a high amplitude ridge east of the Mississippi River Valley will gradually get suppressed to the south as a northern branch upper trough tracks across eastern Canada. The latter of which will send a cold front through the region late Monday night into Tuesday morning. High pressure follows for the midweek period. There is a fair amount of uncertainty though toward the end of the week due to the proximity of the front to the south and its interaction with a northern branch short wave trough. The GFS is dry through the period, while the ECMWF cuts off a southern branch upper low over the Mississippi Valley with precipitation in much closer proximity, and the GGEM has a phased system with potential for a strong low and heavy rainfall Thursday into Friday. GEFS does not differ much from the operational. For the time, have leaned toward a GFS/ECMWF blend and keep rain chances to the south with a dry forecast and high pressure prevailing. The main features of concern will be high heat and humidity on Monday, but heat index values across NYC metro and the Lower Hudson Valley look to fall short of advisory criteria with value in the mid to upper 90s. The key factor will be the depth of the mixed layer and how much drier air can be mixed into the low levels. A veering wind profile ahead of the front may support a drier profile. Secondly, moderate instability and approaching cold front will trigger scattered convection late Monday (pre-frontal trough)and then with the actual cold front Monday night into Tuesday morning. Environment is weakly sheared and only supports isolated strong/severe. Temperatures return to seasonable levels mid week behind the cold front but then gradually warmup as heights builds toward the weekend. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/...
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High pressure remains centered well south of Long Island into tonight. VFR through the TAF period. Light and variable winds this morning. Seabreezes this afternoon, except at KSWF where WSW winds develop by early-mid afternoon. Winds become light and variable throughout again tonight. .OUTLOOK FOR 06Z MONDAY THROUGH THURSDAY... .Late tonight-Monday Afternoon...VFR. SW winds G15-25KT possible Monday afternoon. .Monday Night-Tuesday...Most likely VFR. Low chance of a shower and/or thunderstorm with MVFR possible. NW-N winds G15-20KT possible Tuesday. .Tuesday Night-Thursday...VFR. N-NW winds G15-20KT possible Thursday.
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&& .MARINE... A relaxed pressure gradient over the waters will limit winds to around 10 kt or less through Sunday night. The pressure gradient tightens Monday afternoon, with sustained winds up to around 20 kt and gusts on the coastal ocean waters probably to around 25 kt. This should continue Monday evening. Seas on the coastal ocean waters could reach around 5 ft as a result Monday night. On the non-ocean waters winds should be limited to up to around 15 kt gusting to around 20 kt Monday afternoon and evening. The pressure gradient then slackens over the waters into Tuesday, with winds around 10 kt or less on all the waters around Long Island from Tuesday through Thursday. && .HYDROLOGY... Other than scattered showers/thunderstorms late Monday through Tuesday, no hydrologic issues are anticipated. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...BC/DW NEAR TERM...DS/BC SHORT TERM...BC LONG TERM...DW AVIATION...Maloit MARINE...BC/DW HYDROLOGY...BC/DW EQUIPMENT... is the U.S. government's official web portal to all federal, state and local government web resources and services.