Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 231145 AFDOKX Area Forecast Discussion National Weather Service New York NY 745 AM EDT Wed May 23 2018 .SYNOPSIS... A weak cold front will move south and east of Long Island early this morning. Meanwhile, high pressure will build toward the region through Thursday, then remain through Saturday. Another frontal system will impact the area early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Quick update to adjust PoPs to better reflect radar. Also removed thunder as the last of the pcpn moving through early this morning should remain as only showers through 14z or so. The cold front was a little slower to move southeast, and was moving into the lower Hudson Valley at 10Z. A warm front remains south of the region, across southeastern Pennsylvania into southern New Jersey. Patchy fog remains across the area as well, with light winds and a moist boundary layer. A northern stream trough will remain across eastern Canada and into the northeast once the cold front passes. Clearing will take place late this morning through the afternoon as the trough begins to move slowly east, with slowly rising heights. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... A trough continues to exit the northeast as heights rise across the region tonight as a strong ridge from the Gulf of Mexico to the southern central Canadian plains shifts east. The ridge axis builds toward the area Thursday with a surface high over the region. A dry NW flow will continue tonight through Thursday. Despite plenty of incoming solar radiation Thursday, temperatures are expected to be slightly cooler than Wednesday as the NW flow brings in a cooler and drier airmass from Central Canada. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Vortexes over the Labrador Sea and northern Greenland, and an upper level trough moving into south central Canada at the start of the period will result in the flattening of the upper level ridge extending from the upper Midwest as it shifts eastward into Sat. This will result in a continuation of the warm and increasingly humid weather through the first half of the weekend. Fri will be a bit breezy as the pressure gradient tightens between low pres to the north and high pres sliding off the Mid Atlantic coast. Sat will be the hottest and most humid day with an established SW flow as a result of the offshore high remaining anchored over the western Atlantic. Temps are expected to be in the mid to upper 80s under a sunny sky across much of the local area, possibly even hit the 90 degree mark in some locations of metro NY/NJ. The southerly flow off the cooler waters will result in highs 5-10 degrees cooler along the south shore of Long Island and coastal CT. A cold front will be dropping down from the north on Sat and while the upper level dynamics appear to remain well to the north during peak heating, there is the possibility of a few airmass tstms during the aftn and early eve. A trigger will be needed and any thermal trough or seabreeze boundary would suffice. The GFS appears to be overdone with its pcpn field Sat night as sheared energy tracks towards the region from the west and the front to the north continues to sag southward. Have maintained SCHC PoPs sat night with the boundary moving into the local area if not passing through completely by Sun morning. Global models start to diverge significantly on the details through the remainder of the period, although the general signal is for unsettled weather Sun and Mon with the boundary remaining nearby and a series of shortwaves passing through. Timing of pcpn will need to be refined in later forecasts once a there is better agreement. Another cold front approaches from the west early next week, although timing is once again in question. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
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A cold front moves across the area this morning. A brief period of IFR/MVFR conditions this morning, otherwise becoming VFR. A light W/SW flow at 5 kt or less this morning becomes NW and increase to around 10 kt. A few gusts into the teens will be possible this afternoon. KGON will be in close proximity to a surface trough today which may keep winds W-SW. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/www.weather.gov/zny/n90 KJFK TAF Comments: Moderate to high confidence of winds right of 310 for much of the day. A few gusts into the teens possible the afternoon. Winds back late in the day. The afternoon KJFK haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KLGA TAF Comments: Moderate to high confidence of winds right of 310 for much of the day. A few gusts into the teens possible the afternoon. Winds back late in the day. The afternoon KLGA haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KEWR TAF Comments: Moderate to high confidence of winds right of 310 for much of the day. A few gusts into the teens possible the afternoon. Winds back late in the day. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Winds back late in the day. KHPN TAF Comments: Timing of improvement to VFR may be delayed 1-2 hours. Winds back late in the day. KISP TAF Comments: Winds back late in the day. .OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY... .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.
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&& .MARINE... Updated for weather, mainly across the ocean waters, through 14Z. Winds and seas forecast remains on track. A weak cold front moves slowly across the forecast waters early this morning with showers and isolated thunderstorms exiting the waters as the cold front moves south and east of Long Island. High pressure will build toward the waters today through Thursday. With a weak pressure gradient force across the forecast waters winds and seas will remain below small craft advisory levels. Sub-advsy conds are expected on all waters through Sat night with a strong sfc inversion in place. Winds could approach SCA levels on the ocean waters Sun morning and again Sun night. && .HYDROLOGY... Showers end early this morning with rainfall less than 1/4 inch. No significant hydrologic impacts are anticipated. No hydrologic impacts are expected through Sat. While the details for late this weekend into early next week remain fuzzy, there is the potential for greater than 1/2 inch of rainfall from Sun through next Tue. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...19 NEAR TERM...19 SHORT TERM...19 LONG TERM...24 AVIATION...DW MARINE...24/19 HYDROLOGY...24/19

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