Area Forecast Discussion
Issued by NWS Upton, NY

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262 FXUS61 KOKX 192355 AFDOKX Area Forecast Discussion National Weather Service New York NY 755 PM EDT Tue Jun 19 2018 .SYNOPSIS... Weak high pressure builds into the the region tonight. A cold front crosses the area Wednesday and Wednesday night with an area of low pressure passing to our south. Canadian high pressure builds in through Thursday Night, then gradually slides to the northeast Friday into Friday Night. A frontal system affects the region Saturday into Sunday. High pressure then builds into the area early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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Clear conditions are in place this evening. Dewpoints were running a few degrees less than forecast and temperatures have been running a few warmer than forecast. Temperature and dewpoint grids this evening have been adjusted accordingly to better match observed trends. Lows were kept the same as previously forecast. High pressure continues to build into the region tonight. Northwest flow continues, with continued dry weather and minimal cloud cover. Lows should run around normal, generally from the middle 50s to middle 60s. Min forecast temperatures will be more in the upper 60s in and around the NYC metro area.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... High pressure over the region slides east on Wednesday. We are generally looking at dry conditions on Wednesday, however an increase in clouds can be expected as a cold front and an area of low pressure approaches from the west. There is a low chance for a few showers west of NYC late in the afternoon. Wednesday temperatures will climb into the middle and upper 70s, with a few lower 80 degree readings in and around the NYC metro. Rain will continue to overspread the region wednesday night, as low pressure slides south of the region. There are some differences with the forecast models with respect to the placement of the low and the amount of precipitation. The 12z NAM was a bit of an outlier with well over an inch of QPF. Sided more with the 12z GFS/ECMWF and WPC guidance, with a general half to three quarters of an inch across the southern half of the CWA, with lesser amounts across the Lower Hudson Valley and Southern Connecticut. Precipitable waters increase to 1.75 to around 2" Wednesday night, so there is the potential for locally heavy rainfall as well. Can not rule out a few rumbles of thunder as well. Lows Wednesday night should run a few degrees above normal. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Models in general agreement with the upper air pattern through the period. Mean upper troughing across the NE on Thu, will give way to brief ridging on Friday. The next feature of note will be an upper low over the Central US on Thu/Fri, eventually shearing NE towards the region this weekend as a northern stream trough amplifies south through Ontario/Quebec. A few pieces of energy will work through the NE, before the upper trough axis swings through early next week. This appears to be followed by upper ridging. In terms of sensible weather, tranquil and seasonable late June conditions expected Thursday/Friday as Canadian high pressure builds to the north. Unsettled weather expected Sunday as low pressure track well to the NW, with a warm front moving through the region Saturday, and cold front on Sunday. At this point, appears to be a high shear/low cape situation with warm frontal/prefrontal trough passage Sat into Sat night, bringing threat of showers and a few thunderstorms. Brief very warm and humid interlude on Sunday may allow for a few thunderstorms along the cold front as well. Then return to tranquil and seasonable conditions early next week as Canadian high pressure builds from the northwest. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
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High pressure builds into the region from the north tonight into Wednesday, moving off the New ENgland coast Wednesday afternoon. A wave of low pressure approaches from the west late in the forecast period, toward 00Z Thursday. VFR. Winds N-NE under 10 KT tonight, becoming light and variable outside of the NYC terminals. Light NE to E winds become southerly Wednesday morning into midday. ...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: Amendments for winds early this evening as a sea breeze weakens, with winds under 10 KT, and winds shift back to N, under 10 KT. Amendments possible Wednesday for timing of southerly winds. KLGA TAF Comments: Amendments possible Wednesday for timing of NE winds shifting to E then S. KEWR TAF Comments: Amendments possible Wednesday for timing of developing SE winds. KTEB TAF Comments: Amendments possible Wednesday for timing of developing SE winds, possibly becoming S. KHPN TAF Comments: Amendments possible Wednesday for timing of developing SE winds, possibly becoming S. KISP TAF Comments: Amendments possible Wednesday for timing of developing E winds, becoming S. .OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY... .Wednesday night...Showers likely with MVFR to IFR conditions. lower conds, as low pressure passes to the south. .Thursday...MVFR early with showers ending, then becoming VFR. .Friday...VFR. .Saturday...A chance of showers, possibly a thunderstorm, late Sat into Sat night.. .Sunday...VFR expected. Slight chc of a shower.
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&& .MARINE... High pressure building over the waters will keep winds and seas below SCA levels through Fri. Next chance for SCA conditions may be Sat Night into Sun with moderate S/SW flow ahead of cold front. && .HYDROLOGY...
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Dry conditions are forecast tonight into Wednesday morning. Currently forecasting 1/4 to 3/4 of an inch basin average rainfall from late Wednesday afternoon through Wednesday night with the heaviest amounts across NE NJ, New York City, and Long Island. With very high precipitable waters forecast, there is the potential for locally heavy rainfall with any stronger convection. Areas experiencing locally heavy rainfall could experience minor flooding, mainly of urban and known poor drainage areas. No significant widespread hydrologic impacts are currently expected from Thursday into early next week.
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&& .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...NV NEAR TERM...BC SHORT TERM...BC LONG TERM...NV AVIATION...19 MARINE...BC/NV HYDROLOGY...BC/NV EQUIPMENT...

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