


Area Forecast Discussion
Issued by NWS Upton, NY
Issued by NWS Upton, NY
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887 FXUS61 KOKX 131833 AFDOKX Area Forecast Discussion National Weather Service New York NY 233 PM EDT Sun Jul 13 2025 .SYNOPSIS... Offshore high pressure departs further east tonight. A cold front approaches the region from the west Monday, attempting to move through into Monday night. The frontal boundary likely remains just south of the area for a few days before returning north as a warm front sometime late in the week. This will be followed but a cold frontal passage late week into the weekend. && .NEAR TERM /THROUGH TONIGHT/... High pressure that has been situated off the coast of Nova Scotia exits further out into the Atlantic into tonight, as a cold front over the eastern Great Lakes gradually works east. Some clearing has worked in along much of the coast this afternoon, with interior areas having a more difficult time, though additional stratus develops and rolls in into this evening. Lowered PoPs a bit across NE NJ and the LoHud Valley late today with any activity likely remaining off to the west based on current radar and latest hi res guidance. Still possible a shower or spotty thunderstorm drifts east into this evening, but coverage looks isolated at best with limited forcing and most, if not all, remain dry through this evening. Prefrontal convergence well ahead of an approaching frontal boundary could instigate some showers into the western Lower Hudson Valley overnight, but activity should weaken as it drifts east. With the persistent onshore flow and saturated low levels, in addition to widespread stratus tonight, will have to watch for possible areas of patchy fog or drizzle late, mainly LI and southern CT. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... Ridge axis aloft shifts east of the region as a surface cold front approaches from the west Monday, moving into the region Monday night. Any morning fog or drizzle comes to an end by mid morning, and the stratus blanket attempts to break up into the afternoon. The approach of the frontal system will eventually initiate showers and thunderstorms, though forcing looks relatively weak until later in the day. Looking at the thermo environment, abundant moisture with a tropical like air mass in place and PWATs progged near 2 inches will combine with modest instability, though denser cloud cover could hinder this. Deep layer shear will be lacking, with a piddly wind profile through much of the column. This should keep convection relatively unorganized, but can`t rule out a few strong or damaging wind gusts with any thunderstorm, though the overall severe threat looks limited. Perhaps a bit more of a concern is the potential for higher rainfall rates in the moisture laden environment, particularly for areas west of the Hudson. Hi res guidance, including the 12Z HREF, is signaling potential for pockets of convection producing rates over an inch an hour, mainly over NE NJ and the LoHud Valley. WPC has maintained a marginal risk for excessive rainfall locally, though introduced a slight just off to the south and west. More likely is the potential for minor nuisance flooding as the convection works through, with perhaps a localized flash flood threat. Timing looks mid to late afternoon for western areas, including NE NJ, NYC, and the LoHud Valley, before activity works east across southern CT and Long Island into the evening hours, and could linger into the overnight as the weakening boundary slows or hangs up over the region. && .LONG TERM /TUESDAY THROUGH SATURDAY/... ***Key Points*** *Potential remains for several days of high heat and humidity this week. The higher confidence is now for Wednesday through Friday, with widespread max heat index values forecast to be 95 to around 100 (Heat Advisory criteria). *A relatively active pattern is expected with chances for several days of afternoon showers and thunderstorms. A frontal boundary will likely stall just offshore and linger near the area through midweek before returning north as a warm front. A cold front will then follow at the end of the week into the weekend. Aloft, the pattern stays the same through the period. Although we are under some high heights, we are somewhat on the eastern end of a broad upper level trough centered over central Canada and few shortwaves likely pass through. With strong Bermuda high in place, a S/SW flow will allow plenty of moisture to be sent our way. This combined with above normal high temperatures brings some potential for a heat wave, with widespread heat index values of 95 to around 100 (Heat Advisory criteria) currently expected Wednesday through Friday. Temperatures have trended down a bit, especially for Tuesday which now looks like it may not reach Heat Advisory criteria. However, there still is uncertainty especially given the potential for convection and slight inconsistencies in a late week frontal system among the guidance. The NBM was followed for highs but did manually lower afternoon dewpoints a few degrees when better mixing is expected. This still gave dewpoints in the lower to mid 70s. Too early to talk specifics when it comes to severe or flooding concerns with the aforementioned convection. These details will be ironed over the next few days. There is plenty of moisture around with pwats 1.50-2.00+ for much of the period so any convection that does develop will likely be able to produce heavy downpours. As for severe, while we are pretty unstable, shear looks weak through much of the period, with some better values as we get into late week and the weekend. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Weak offshore high pressure drifts east through tonight, and remains offshore through Monday. MVFR ceilings remain across much of the area, with VFR east of the NYC terminals and into coastal Connecticut with a light southeast to south flow. By around 19Z ceilings are expected to improve to VFR at the NYC terminals. The improved conditions will be short-lived as ceilings lower to MVFR during the early evening, and then to IFR east of the NYC terminals late tonight. IFR conditions are possible late tonight into early Monday morning at the NYC metro terminals. Conditions improve to VFR around midday or into Monday afternoon at all the terminals. There is a lot of uncertainty with the timing of lowering conditions, and areal extent of IFR, and possible LIFR. Patchy drizzle and fog is also possible late tonight into early Monday morning. Light SE winds up to 10kt this afternoon becoming generally light and variable tonight. A more southerly flow develops Monday with speeds to around 10kt. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Amendments expected due to changes in flight categories through the forecast period with uncertainties of flight category changes and timing. .OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY... Monday afternoon: MVFR ceilings possible early afternoon, then becoming VFR. MVFR possible in thunderstorms mid afternoon into the evening. A chance of thunderstorms overnight. A few storms could produce brief heavy rainfall late Monday afternoon into the evening. Tuesday-Friday: Mainly VFR. MVFR in showers or thunderstorms each afternoon and evening. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Patchy dense fog is possible on the local coastal waters Monday morning. With a weak pressure gradient, winds and waves likely remain below Small Craft Advisory criteria through the coming weekend. However, a relatively active pattern is expected next week with chances of afternoon showers and thunderstorms for several days. Winds and waves will be higher in any storms. && .HYDROLOGY... Showers and thunderstorms move through Monday afternoon and evening, and could produce locally heavy downpours with rainfall rates that briefly exceed an inch per hour. This could lead to areas of minor, nuisance flooding, with a localized flash flood risk, especially across urbanized NE NJ. At this time, there are no significant flood concerns Tuesday through next weekend. && .TIDES/COASTAL FLOODING... For Atlantic Ocean beaches, the rip current risk today and Monday is moderate with an onshore flow near 10 kt, a 3 ft swell from the southeast at a 7 to 8 sec, and added onshore swells, one of which is a long period swell. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...DR/JT NEAR TERM...DR SHORT TERM...DR LONG TERM...JT AVIATION...MET MARINE...DR/JT HYDROLOGY...DR/JT TIDES/COASTAL FLOODING...