465 FXUS61 KOKX 131102 AFDOKXArea Forecast Discussion National Weather Service New York NY 702 AM EDT Sat Sep 13 2025
.SYNOPSIS... High pressure over the area gradually weakens this weekend while slowly moving offshore. A weak cold front approaches Sunday and moves across Sunday night. A new area of high pressure then builds in from the north and west for early next week. A weak low to the south may graze the area Wednesday night into Thursday, followed by weak high pressure on Friday.
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.NEAR TERM /UNTIL 6 PM THIS EVENING/... Just made some minor adjustments with temperatures, dewpoints, cloud coverage and patchy fog to better match with observed trends. Otherwise, forecast remains on track.
Into the morning hours, mid level clouds more prevalent across western areas. In addition, especially outside of clouds, patchy fog for locations reaching saturation, particularly inland and rural valley sections.
During the day, synoptic southerly flow from high pressure moving offshore but overall weakening. A little bit of convergence with sea breeze enhancement and some positive vorticity advection aloft will enable for a few rain showers to develop. Model CAPE limited to near 100 J/kg or less, so left out thunder. The sparse coverage of showers forecast as denoted from a few CAMs limited POPs to slight chance. Some locations due to ambient drier low levels may end up just getting some sprinkles.
Forecast high temperatures range from the lower 70s for eastern coastline to lower 80s for parts of interior north and west of NYC. These values are from NBM. The NBM high temperatures near the coast seem to be in general agreement with a consensus of MOS but are a few degrees higher for urban and interior areas.
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.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... For tonight, the loss of diurnal heating will make for lessening instability. Any remaining showers are expected to dissipate.
Otherwise, weakening high pressure will allow for a dry airmass with southerly light winds becoming more variable. Patchy fog will be possible late at night into early Sunday morning for those locations that radiatively cool more, mostly across the interior where winds become nearly calm.
Forecast lows tonight are mainly in the upper 50s to lower 60s.
Weakening high pressure will allow for a weak cold front to approach the region Sunday. This weak cold front will move across the region Sunday night.
More low level warm air advection expected for Sunday, allowing for warmer surface temperatures. These will be several degrees warmer than the previous day. Forecast high temperatures range from the mid 70s to mid 80s.
Models convey stronger shortwave energy aloft as diagnosed from more positive vorticity advection along with more instability (more between 100 and 200 J/kg CAPE) will present a possibility for showers and thunderstorms. The front with its weakening structure and limited moisture content will have associated convective coverage limited to no more than sparse. The POPs as a result are mostly slight chance to low end chance with low end chance across north and eastern portions of New London CT. The CAMs depict sparse convection developing during the afternoon, mostly across the interior.
Post cold front, temperatures trend down slightly as winds transition to more northerly and eventually more easterly. Dry conditions will remain thereafter through Monday night. Lows forecast Sunday night range from the lower 50s to mid 60s. Forecast highs on Monday return to a lower 70s to lower 80s range. Lows forecast Monday night range mainly from mid 50s to lower 60s.
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.LONG TERM /TUESDAY THROUGH FRIDAY/... Key Points:
* Dry conditions with seasonable temperatures are forecast through Wednesday afternoon.
* A weak low to the south may graze the area Wednesday night into Thursday.
* Dry and warmer conditions are possible for Friday.
Ridging will continue to build over much of the eastern CONUS Monday and Tuesday. The modeling still indicates energy getting stuck underneath the ridge across the southeast, likely forming a broad cutoff low by mid week. The uncertainty lies with its location by later this week, with the GFS faster (Wed night-Thu) and ECMWF slower (Thu-Thu night). NBM guidance sides with the fast GFS idea. After this low pulls away, weak sfc ridging should return with above normal temps for Fri.
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.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... High pressure over the area will shift just offshore today. A weakening cold front will approach from the northwest this afternoon.
At 07Z patchy MVFR cigs were near KLGA/KISP/KHPN/KBDR attm, with even lower IFR cigs just NE of KHPN. Can`t rule out expansion of these patchy cigs SW to the other NYC metro terminals overnight into part of the AM push so this will have to be watched closely.
Daytime Sat should see VFR cond with some BKN mid level cigs developing in the afternoon. Can`t rule out a stray late mid to late afternoon shower in spots, mainly near KSWF/KHPN/KBDR.
Light winds overnight should become mainly SSE-S 5-10 kt during the late morning and afternoon, except at KSWF where light WSW flow expected.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
May have to watch for possible tempo MVFR cigs before 13Z-14Z.
.OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
Late tonight: VFR.
Sunday: Mainly VFR, Slight chance of an afternoon shower or tstm as another weak cold front approaches.
Sunday night through Wednesday: VFR.
Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90
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.MARINE... With high pressure staying nearby and weakening, pressure gradient will be weakening also. Winds and seas are forecast to remain well below SCA thresholds through early next week.
Weak pressure gradient remains with weak low pressure approaching nearby potentially for middle of next week, so conditions look to stay below SCA thresholds.
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.HYDROLOGY... Any rainfall this weekend is expected to be quite limited in both temporal and spatial coverage. As such, no flooding is expected and the rain is not expected to sufficiently wet the ground. Less than a tenth of an inch of rainfall is forecast.
There are no hydrologic concerns through next week.
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.TIDES/COASTAL FLOODING... Rip current risk for ocean beaches this weekend is low with winds staying light and less onshore swell. Southerly winds stay mostly in 5-10 kt range and waves stay near 2-3 ft.
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.OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None.
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SYNOPSIS...JM NEAR TERM...JM SHORT TERM...JM LONG TERM...BG AVIATION...BG MARINE...BG/JM HYDROLOGY...BG/JM TIDES/COASTAL FLOODING...JM
NWS OKX Office Area Forecast Discussion