


Area Forecast Discussion
Issued by NWS Upton, NY
Issued by NWS Upton, NY
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928 FXUS61 KOKX 032100 AFDOKX Area Forecast Discussion National Weather Service New York NY 500 PM EDT Wed Sep 3 2025 .SYNOPSIS... High pressure along the Northeast and Mid Atlantic coasts will drift slowly east and offshore through Thursday afternoon. A cold front will approach Thursday night and wash out over the area on Friday, then another cold front will approach and move through from Saturday afternoon into Sunday. High pressure will then build in from the Midwest early next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Dry conditions will continue under mostly clear skies and a light S flow. As was the case last night, there could be some patchy river and valley fog after midnight, maybe some patchy low clouds in spots across SE CT and eastern Long Island. Low temps will range form the lower 60s in/just outside NYC, to the lower 50s in sheltered inland valley locations and in the Long Island Pine Barrens. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... A subtle increase in temperatures is expected Thursday via WAA S flow and a slight increase in heights aloft before a cold frontal approach Thu night. High temps on Thu should reach the lower 80s in most places away from south facing shorelines, where mid/upper 70s are expected. As shortwave energy rounds the base of an upper trough to the west along with an approaching cold front to provide lift, chances for showers and possibly a tstm will increase Thu night, especially NW of NYC where likely PoP is fcst. These chances will spread east into S CT and Long Island later in the evening and overnight. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... By late this week, the region lies on the southeast periphery of an anomalous 3-4 std closed low trough situated over Ontario and the Upper Great Lakes, with ridging offshore. At the surface, a series of cold fronts approach and attempt to move through the region through Sunday. Clouds to start Friday with the first of the frontal boundaries attempting to work through before washing out. Cloud cover erodes into late morning, and sets up a warm September afternoon under mostly sunny skies. Soundings mix above 800 mb, and this could allow for some gusts up to 25 mph Friday and Saturday afternoons. 850 mb temps rise into the upper teens (C), and should work down into the low to mid 80s for much of the local Tri State. Humidity creeps up with the warmth, and heat indices may approach lower 90s in the hottest locales of urban NE NJ, with 80s elsewhere. Best chance for wet weather looks to be Saturday afternoon into the first half of Saturday night as more potent shortwave energy rounds the base of the trough and pushes a cold front closer. Deep southwesterly flow between the offshore ridging and troughing to the NW will usher in a moister air mass ahead of the front. Global models prog PW increasing toward 2 inches, and with it, the chance for heavy downpours with any convection that is able to develop, particularly north and west of NYC. Still some uncertainty this far out on timing of the energy and boundary, but potential for some thunderstorm activity along the front/pre-frontal trough Sat aft/eve, though it still appears most activity with the front could be post-frontal and off to the NW of the region with best forcing displaced well NW of the region. Lessening chances for thunderstorms moving east across LI and SE CT, but could see some remnant showers work in during the evening and nighttime hours. The NW displacement of the trough makes for a slow progress of the cold front through the region Saturday night, likely not cleanly working through entirely until Sunday with trough axis passage and secondary front, and this could lead to a few additional showers. Humidity looks to lower significantly across the forecast area by Sunday night. Otherwise in the wake of the secondary passage, cooling down early next week, with temperatures going from about 5 degrees above normal, to around 5 below it as moderating Canadian surface high pressure builds in from the west. && .AVIATION /21Z WEDNESDAY THROUGH MONDAY/... High pressure over the terminals will move offshore on Thursday. This will allow a cold front to approach from the west. S to SE winds this afternoon around 5-10 kt, Will become light and variable tonight. Winds on Thursday will once again be from the S/SE with speeds 5-10kt in the morning and 10-15kt with some gusts 20-25kt in the afternoon. The best chance for gusts will be along the coast. VFR conditions through the TAF period. There is a low chance of stratus and patchy fog developing again early Thursday morning with an onshore flow, but confidence remains low. The best chances are across the eastern Long Island and southern Connecticut. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... No amendments expected. .OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY... Thursday afternoon: VFR with S gusts 20-25kt. MVFR or lower possible in showers and isolated thunderstorms at night. Friday: MVFR or lower possible in any showers and isolated thunderstorms mainly in the morning. S gusts 20-25kt. Saturday: Mainly VFR. Low chance of MVFR in showers. Sunday and Monday: VFR. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Sub-SCA cond expected into Thu night. There is still potential for a brief period of 25-kt gusts in S flow late day Thu on the ocean waters just E of Sandy Hook. SW winds gusting toward 25 kt likely develop on the coastal ocean waters Friday afternoon, and could linger into Saturday as well with a cold frontal passage. Ocean seas will also build toward 5 ft during this time, especially E of Fire Island Inlet. Winds subside Sat afternoon into evening, shifting NW Sat night, with seas falling below SCA. Conditions then appear to remain under SCA criteria into early next week. && .FIRE WEATHER... On Thursday, S winds increase to 10 to 15 mph with gusts 20-25 mph, highest in the NYC metro area up into the lower Hudson Valley. Min RH in the afternoon will be as low as 40-45% across NE NJ up into the lower Hudson Valley, 45-50% across southern CT, and 50-55% across Long Island. KBDI values are also running over 300 for most of the CWA. With this in mind, in collaboration with NYS DEC and WFO ALY decided to issue SPS for elevated fire growth/spread potential for the lower Hudson Valley for Thu 10 AM to 7 PM. Wetting rainfall expected mainly NW of NYC Thu night, with slight chance of tstms. Another round of wetting rains expected from Sat afternoon into Sunday morning, especially from the NYC metro area north/west. && .HYDROLOGY... Showers and thunderstorms associated with a cold frontal passage on Saturday could produce localized downpours that result could cause minor nuisance flooding in urban and poor drainage locales. The overall flash flood risk is low. && .TIDES/COASTAL FLOODING... There is a moderate rip current risk for NYC and Nassau beaches on Thursday with 2 to 3 ft ESE swells at 8 seconds, and an onshore wind up to 15 kt, with higher gusts. A bit lighter flow going east should mitigate the risk a bit, and low is forecast for Suffolk beaches on Thursday. The rip current risk is moderate across all local ocean beaches on Friday, with increasing 3 to 4 ft S swells and sustained winds near 15 kt. It`s possible that the risk may need an upward adjustment in subsequent forecasts. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...BG/DR NEAR TERM...BG SHORT TERM...BG LONG TERM...DR AVIATION...BC MARINE...BG/DR FIRE WEATHER... HYDROLOGY...BG/DR TIDES/COASTAL FLOODING...