Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 291548 AFDOKX Area Forecast Discussion National Weather Service New York NY 1148 AM EDT WED JUN 29 2016 .SYNOPSIS... A cold front will move slowly slides east across the Tri-State into tonight, followed by weak high pressure building in through Thursday, then weakening over the region into Friday. A cold front moves over the Tri-State from Friday night into Saturday morning. High pressure builds in behind the front and prevails through early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A 700-500 hPa trough will push into the area this afternoon, as its core lifts to the northeast into eastern Quebec. 12z KOKX and KALY soundings show a basically dry atmosphere above around 650 hPa, with a cap around the same level. These two limiting factors should keep most, if not all the area dry this afternoon. However, cannot completely rule out a stray shower/thunderstorm due to dynamical forcing from the aforementioned trough. Have confined the mention of such in the grids/forecast mainly to SE CT, as this is the area experiencing the best dynamics, and having the most unstable airmass (CAPES 600-750 J/kg). Note: the HRRR is over doing the extent of convection currently, and so is not being trusted in its current run for convective coverage/placement. Highs this afternoon will be near normal in the immediate NYC Metro and run up to around 5 degrees above normal elsewhere, consistent with a blend of MAV/MET/ECS/LAV guidance and NAM and HRRR 2-meter temperatures. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Dry conditions should persist through Thursday with high pressure continuing to build in. Temperatures will continue to be seasonable, with humidity levels continuing to drop into Thursday. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Upper low south of Hudson Bay will rotate through the mean trough and pass through eastern Canada and the Northeast by the close of the weekend. The latter of which will send a cold front across the area late Friday night into Saturday morning, preceded by a round of showers and thunderstorms Friday afternoon and evening along and ahead of a pre-frontal trough. There is the potential for some organization with moderate deep-layer shear and CAPES over 1000 J/KG across much of the area. In addition, models are pointing toward showers developing overnight Thursday as moisture returns around the western periphery of offshore high pressure, interacting with mid level short wave energy. The forecast is slowly trending in this direction. High pressure follows for the weekend into early next week. The 00Z GFS bring a southern branch system close enough to the area Tuesday for showers, however, the ECMWF is suppressed to the south. Subsequent model trends will need to be watched, but for the time will keep the forecast dry. Temperatures continue to remain near seasonable levels throughout the period. && .AVIATION /16Z WEDNESDAY THROUGH SUNDAY/... A cold front dissipates over eastern Long Island today. High pressure otherwise slowly builds in. VFR. NW-W winds at 10 kt or less outside of sea breezes. Cannot rule out an isolated TSTM mainly E of NYC near the cold front and possibly along developing sea breeze fronts. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/ KJFK TAF Comments: Amendments possible for timing the development of sea breezes. Timing within 2 hours. KLGA TAF Comments: Amendments possible for timing the movement of the sea breeze toward KLGA. KEWR TAF Comments: Amendments possible for timing the movement of the sea breeze toward KEWR. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: No unscheduled amendments expected. KHPN TAF Comments: No unscheduled amendments expected. KISP TAF Comments: Timing of sea breeze shift to sw might not occur until closer to 18z. Chc TSTM this aftn. .OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY... .Thursday through Friday morning...VFR. .Friday afternoon and night...MVFR or IFR conditions possible in showers/tstms. .Saturday and Sunday...VFR. && .MARINE... Made minor changes this update to reflect the latest trends in observations and guidance. A relaxed pressure gradient over the waters will keep winds to 10 kt or less through Thursday. A lack of any significant swell will keep seas to 3 ft or less and waves to 1 ft or less over the waters around Long Island through this period as well. Winds and seas are forecast to remain below small craft advisory levels from Thursday night through the holiday weekend. && .HYDROLOGY... No significant rainfall is expected through Friday morning. Scattered showers and thunderstorms are possible Friday afternoon into early Saturday. Antecedent conditions are very dry, so widespread hydrology issues are not expected. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...JP/DW NEAR TERM...Maloit/JP SHORT TERM...JP LONG TERM...DW AVIATION...GC/JC MARINE...Maloit/JP/DW HYDROLOGY...JP is the U.S. government's official web portal to all federal, state and local government web resources and services.