Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 281152 AFDOKX Area Forecast Discussion National Weather Service New York NY 752 AM EDT TUE JUN 28 2016 .SYNOPSIS...
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A cold front over western Pennsylvania this morning will move slowly east today passing across the area on Wednesday. Weak high pressure returns for Thursday through Friday. Another cold front then approaches and passes through late Friday night into Saturday. High pressure builds in behind the front Sunday and Monday.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Dissipating band of showers across far eastern LI will work east through mid morning. For the rest of the morning, there will be a low chance of showers until airmass destabilizes enough to warrant the mention of thunderstorms this afternoon. However, did keep LI and CT showers through the day based on marine air keeping the region stable. In fact, any strong convection across the interior is not likely until late this afternoon. There is definitely a good deal of uncertainty as to whether this activity will be able to reach the coast late today into this evening. Otherwise, low stratus and patchy fog, locally dense will prevail until around 15z. A short wave trough will be moving SE toward the area along with its` surface cold front reflection. With abundant low level moisture in place and the cold front serving as the trigger, SCT TSTMS are forecast to develop ahead of the cold front and move toward the Lower Hudson Valley and Northern NJ aft 18z. The degree of surface based instability is uncertain based on clouds dissipating upstream. In any case, there is a Slight Risk or severe TSTMs mainly for Orange County and a Marginal Risk further east across NYC and SW CT...mainly aft 20z with damaging winds being the primary threat. Based on high sfc dew points and precipitable water contents, can not rule out isolated flash flooding of low lying and poor drainage areas. An Outlook was issued for these potential hazards and impacts.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... The short wave trough is forecast to gradually move east with the trough axis nearly overhead by 6 pm Wednesday. Any potential severe TSTMs Tuesday evening should end by midnight with showers ending by 10z Wednesday. SCT instability TSTMs are possible aft 16z Wednesday with the approach of the short wave trough axis. Temperatures are forecast near normal through the period. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... As has been the case for the last several weeks, still no hot weather on tap for the region with minor fluctuations around the mean. The mean upper trough will continue to reside across eastern Canada, the Great Lakes, and Northeast, while an amplified upper ridge over the western U.S. gradually flattens into early next week. At the same time, an upper low near Hudson Bay translates east. At the surface, weak high pressure over the Midwest builds into the area Thursday and then offshore Thursday night ahead of an approaching cold front and pre-frontal trough. The latter of which is associated with the upper low/trough working across eastern Canada. There is a chance of showers and thunderstorms Friday into Friday night with the best chance being across the interior where the greatest instability will exist. Deep-layer shear increases with the approaching upper trough. Dry air could be a limiting factor for any organization. Cold front works east of the area Saturday morning with high pressure to follow through early next week. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/...
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A cold front approaches later today and passes through the region late tonight through Wednesday morning. S/SE winds 5-10 KT will increase to 10-15 KT later today. MVFR/IFR conditions in fog/stratus. An area of showers west of KNYC will pass through sometime from 14Z-18Z. Will TEMPO showers for KEWR/KTEB from 12Z-14Z. Showers possible for KLGA/KJFK from 13-15Z, but will leave out of TAF for now. Cold front approaches late in the day. SHRA/TSRA will develop north and west of KNYC terminals and track east. Will carry TEMPO groups for KNYC and interior terminals for TSRA. For eastern terminals, will carry TEMPO groups for SHRA. Rain/stratus/fog moves into the terminals after 03Z with IFR conditions. Cold front passes through around daybreak Wednesday. Rain tapers off. Conditions will improve through Wednesday morning. ...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: Low confidence in the forecast. AMDs expected throughout the day for changes in flight categories. KLGA TAF Comments: Low confidence in the forecast. AMDs expected throughout the day for changes in flight categories. KEWR TAF Comments: Low confidence in the forecast. AMDs expected throughout the day for changes in flight categories. The afternoon KEWR haze potential forecast is YELLOW...which implies slant range visibility 4-6SM outside of cloud. KTEB TAF Comments: Low confidence in the forecast. AMDs expected throughout the day for changes in flight categories. KHPN TAF Comments: Low confidence in the forecast. IFR conditions likely through most of the day. KISP TAF Comments: Low confidence in the forecast. AMDs expected throughout the day for changes in flight categories. .OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY... .Wednesday morning...MVFR and IFR/lower (coastal terminals) conditions possible via morning fog/low clouds and rain. .Wednesday afternoon through Friday morning...VFR. .Friday night...MVFR or IFR conditions possible in showers/tstms. .Saturday...Mainly VFR.
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&& .MARINE... Winds and seas are forecast to generally remain below Small Craft Advisory/SCA levels of 25 kt and 5 feet across the Atlantic Ocean coastal waters through the period. This Morning...Vsby of 1 to 3 nm possible in patchy fog with scattered showers. Late Afternoon through Tonight...Scattered TSTMs are possible with the approach of a cold front along with Vsby of 1 to 3 NM in patchy fog. Cold frontal passages with wind shifts are forecast late Wednesday and Friday night. && .HYDROLOGY... This Morning: Up to 1/2-inch rainfall is possible across Long Island and Southern CT. This Afternoon through Tonight: 1/4 to 3/4-inches possible with isolated higher amounts in heavier showers and SCT TSTMS. Can not rule out isolated flash flooding of low lying poor drainage areas. Friday Afternoon and Evening: Scattered showers and thunderstorms may produce localized heavy rainfall, mainly north and west of NYC. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...GC/DW NEAR TERM...GC/DW SHORT TERM...GC LONG TERM...DW AVIATION...MPS MARINE...GC/DW HYDROLOGY...GC/DW

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