861 FXUS61 KOKX 242322 AFDOKXArea Forecast Discussion National Weather Service New York NY 722 PM EDT Wed Sep 24 2025
.SYNOPSIS... A frontal boundary will remain nearly stationary across the area through much of the night before lifting northward Thursday morning as low pressure tracks up into the eastern Great Lakes. A pre-frontal trough will follow Thursday evening and then a cold frontal passage Friday morning. Weak high pressure briefly builds into the area Friday night into Saturday. There will be chances for showers through early next week until stronger high pressure builds into the area from Canada.
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.NEAR TERM /THROUGH THURSDAY/... A closed upper low over the Great Lakes gets dislodged as northern branch energy kicks the system eastward late tonight into Thursday. A stationary front will remain across the area for much of the night, but then lifts northward Thursday morning as surface low pressure lifts up into the eastern Great Lakes. The latter of which will also send a pre-frontal trough and cold front toward the area.
Anomalously high PWAT values (+2-3SD) increasing to around 2 inches combined with deep-layered lift will produce rounds of showers and embedded thunderstorm from mainly after midnight tonight into Thursday. Anything before then should be relatively isolated. Instability during this time is modest 500-1000 J/kg, possibly a bit higher Thursday afternoon/early evening north and west of the NYC metro. SPC has the area under a marginal risk for severe, which means there is the potential for isolated severe. However, the main issue will be brief heavy downpours. SPC HREF showing low probabilities for an inch/hour and 3"/3hr. The storms look progressive enough to limit the flood threat. However, event totals will likely average 1 to 2 inches with localized higher amounts. NBM probs for 1 to 2 inches are pretty high, with the latter 50 to 70 percent from NYC north into the Lower Hudson Valley. SPC HREF PMM 24-hr QPF has amounts of 2 to 3 inches in narrow bands. This may represent a good upper end. The good news is the FFG remains high do to the prolonged stretch of dry weather coming out of summer. Thus, expect most flooding issues to be of the minor nuisance variety.
The area will get into the warm sector Thursday afternoon and activity likely becomes more scattered or isolated in nature ahead of the pre-frontal trough. CAMs all show a line of convection with the pre-frontal trough from late afternoon into early evening for locations north and west of NYC. This would be the time for the best chance of isolated severe weather.
It will remain warm and humid with lows about 10 degrees above normal tonight. Highs on Thursday will be tempered by the cloud cover and rain, but still a few degrees above normal.
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.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/... A line of convection associated with the pre-frontal trough will work across the remainder of the forecast area Thursday night with pockets of heavy rain, especially across LI and coastal CT. Rain chances will diminish from west to east through Friday morning with mainly showers by daybreak. The cold front will pass through mainly dry in the morning. However, with the upper trough axis pivoting through the area Friday, an isolated shower cannot be ruled out.
Above normal temperatures will continue during this time with Friday highs even warmer behind the front due to much drier air. Many locations will top out around 80 in a westerly flow.
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.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... A stalled upr trof over the Appalachians will produce chances for shwrs Sun into Tue in a mild, humid environment. Although it is not expected to rain the entire period, pieces of energy embedded in the flow should act on the available moisture to produce shwrs at times. Do to the amount of moisture expected attm, added in some fog for Sat ngt and Sun ngt.
A strong Canadian high in the 1030s is modeled to begin building into the area by late Tue. This would result in an increasing nely llvl flow and a general drying of the airmass, reducing pcpn chances and cloud cover.
Stuck with the NBM for the fcst outside of the addition of fog. Temps abv normal thru at least Mon, then falling blw normal by Wed.
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.AVIATION /00Z THURSDAY THROUGH MONDAY/... A stationary front remains nearby tonight. The front will lift north as a warm front late tonight into Thursday.
VFR cond lower to MVFR this evening, then mainly IFR overnight. Mainly LIFR ceilings develop at the CT/Long Island terminals overnight as showers become more widespread. Showers become more widespread for the late evening, and especially during the overnight into Thursday morning.
Winds will be light out of the SE throughout tonight, then S closer to 8-13 kt by Thu afternoon, especially at the NYC metros and closer to the coast as the warm front starts to lift north. Some spots could see corresponding flight cat improvement to MVFR after 16Z, and as late as 20-21Z Thu further east. Any improvement may be less and of shorter duration for eastern most terminals.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
AMD expected with lowering flight CATs overnight. Uncertainty exists around any improvement Thursday afternoon with AMD also possible through the day.
.OUTLOOK FOR 00Z FRIDAY THROUGH SUNDAY...
Thursday night: Periods of MVFR or lower cond with showers and isolated tstms possible, mostly before midnight. Slow and gradual improvement to MVFR and VFR later at night. Winds becoming SW.
Friday and Saturday: VFR.
Sunday: Chance of showers with MVFR cond, mainly at the NYC metro and Long Island terminals.
Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90
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.MARINE... A strengthening southerly flow ahead of an approaching cold front on Thursday could produce a period of 5 ft seas on the ocean late in the day and into the night. Confidence was low and used a blend of the NWPS and Wavewatch to account for a recent high bias in the NWPS. Wind and seas will subside heading into Friday morning.
Winds and seas are modeled to remain blw sca lvls Sun into Mon. Winds and seas could build to sca lvls Mon ngt, especially on the ocean.
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.HYDROLOGY... Showers and thunderstorms will produce widespread rainfall of 1-2 inches, with locally higher amounts possible, tonight into Thursday. With the potential of brief moderate to heavy rainfall, expect brief nuisance flooding in urban and poor drainage areas. Antecedent conditions have been notably dry though, so the risk for flash flooding is low.
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.TIDES/COASTAL FLOODING... There is a high rip current risk Thu due to swell and sly winds. There is a moderate to high risk for Fri, depending on how quickly swell subsides.
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.OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...High Risk for Rip Currents through Thursday evening for NYZ075-080- 081-178-179. NJ...None. MARINE...None.
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SYNOPSIS...JMC/DW NEAR TERM...DW SHORT TERM...DW LONG TERM...JMC AVIATION...JE MARINE...JMC/DW HYDROLOGY...JMC/DW TIDES/COASTAL FLOODING...
NWS OKX Office Area Forecast Discussion