


Area Forecast Discussion
Issued by NWS Upton, NY
Issued by NWS Upton, NY
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162 FXUS61 KOKX 082209 AFDOKX Area Forecast Discussion National Weather Service New York NY 609 PM EDT Tue Jul 8 2025 .SYNOPSIS... A cold front stalls near the forecast area through Thursday night, then either remains stalled to the south Friday into Saturday or washes out altogether. Another frontal system may pass to the north Sunday into Monday. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... A slow-moving cold front will stall over the area tonight, providing convergence and lift needed to continue showers and thunderstorms through the first half of tonight. The three main threats with this frontal boundary are flooding, severe thunderstorms and continued heat. A Flood Watch remains in effect through 2 AM. The stalled boundary may allow for some training with parallel motion of storms to the frontal boundary. Additionally, sea breezes across Long Island and southern CT will allow for convergence and lift there as well, out ahead of the frontal boundary, with storms also moving parallel to the sea breezes. The morning sounding showed PW of 2 inches, near the max of the local climatology for today, and NWP models showing 2-2.5 inches into tonight all indicating that upwards of 2 inches of rain could fall in the heaviest showers/thunderstorms. Also, surface dewpoints are well into the 70s. MLCAPE on the order of 1000 to 2000+ J/kg and deep warm cloud layer also point to flooding. Storms seem to be moving at a reasonable speed to preclude flooding due to slow movers, but again, training is possible, and will have to watch for outflows from previous storms interacting with other boundaries, such as other storms or the sea breezes. CAM`s are still showing some uncertainty with timing, as the 3km NAMNest showed the bulk of the heavy rain moving through as late as 11 PM for western portions of the forecast area. Thus, there continues to be the potential for the Flood Watch to be extended in time overnight. A Severe Thunderstorm watch also remains in effect for NE NJ, NYC, the Lower Hudson Valley, and SW CT until 9 PM. A couple of severe thunderstorms have already occurred, and with the aforementioned features for convergence and lift, high moisture content of the atmosphere, and modest instability, the severe threat will continue into early this evening, with the primary threat of damaging winds, with gusts up to 65 mph. An isolated gust up to 70 mph cannot be ruled out. With warm rain processes, large hail formation is less likely in this environment. Heat Advisories remain in effect through 8 PM. Observations from NE NJ across the NYC metro area up into interior SW CT and western Long Island still show heat index values 95-100 as of 6 PM. As cloud cover increases from storms and especially as we approach sunset, these conditions will improve, however it will still be warm and humid overnight. With the loss of the daytime heating and instability, storms should weaken after about 10 with the threat for flooding ending by 2 AM. Patchy fog is possible late tonight, mainly over eastern areas. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/... Somewhat cooler temperatures on Wednesday and lower dew points may preclude the need for a Heat Advisory. Highs are expected to be in the upper 80s to lower 90s, with index values approaching the mid 90s. So, it is marginal, but Heat Advisories may need to be issued once again for Wednesday. Temperatures cool slightly more by Thursday. With the cold front in the vicinity, shower and thunderstorms are in the forecast for both days, though just a slight chance for Wednesday and better chances for Thursday, as weak areas of low pressure ride along the boundary and aid in any weak lift that might be present with the front. SPC has a small portion of the area in a marginal risk for severe thunderstorms, which includes southern portions of NE NJ and SW portions of SW portions of NYC. Flooding will also continue to be a concern as the air mass really does not change much and very humid conditions remain in place. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... A stalling front eventually pushes south of the area Thursday night as a midlevel shortwave and upper low exits northeast in Canada. This front will then either remain stalled nearby or washout altogether into the weekend. At the same time, most guidance show a weak ridge building Friday into Saturday. Unfortunately, global guidance really varies on solutions Sunday into Monday. Some bring another frontal system Sunday into Monday night to our north while others keep this system too far north to impact us, opting for building high pressure at the surface instead. Generally southerly flow is expected for most of the long-term period. This should keep dewpoints and atmospheric moisture high and continue chances for daily showers and thunderstorms Friday through Monday. Mainly slight chance POPs east with low-end chance POPs west where daily instability from daytime heating could be stronger. Temperatures through the long-term period will generally be close to just above climatological norms. Highs each day will be in the mid 80s to low 90s. Lows each night will be in the mid 60s to mid 70s. However, the difference between NBM`s 25th and 75th percentiles for max temperatures is about 15 degrees Saturday through Monday, further highlighting the uncertainty and disagreement among the guidance in the long-term period. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/... A weak cold front approaches this eve and passes offshore Wed mrng. VFR late this aftn except for isold-sct tstms. A better chance for more organized clusters of tstms aft 21Z into this eve. There is still a little uncertainty with timing. As a result, the prob30 was maintained. Main window attm however remains 22-02Z. Areas of MVFR possible tngt, then improvement to VFR on Wed. Chance for another round of tstms late Wed with a prob30 started at 23Z. High variability in wind direction thru the TAF period due to proximity of the front and tstms. In general, a W-SW flow thru today, becoming NW by Wed mrng, then shifting back to the S/SW aft 18Z Wed. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Variability in wind direction expected this aftn and eve due to position of the front and impacts of nearby tstms. Still some uncertainty with exact timing and coverage of shwrs and tstms. Main window for activity likely 22-02Z. .OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY... Wed-Fri: Periods of shwrs and tstms possible. Mainly VFR outside of shwrs and tstms. Sat-Sun: Mainly VFR. A chance for aftn/eve shwrs and tstms. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... A diminishing SE swell will allow seas to diminish this evening. SCAs continue form Fire Island Inlet through Montauk. The SCA from Fire Island inlet to Moriches inlet may be need to be cancelled within the next few hours. Otherwise, the SCAs are in effect until 2 am. Thereafter, with a weak pressure gradient, winds and waves stay below SCA criteria through Thursday. && .HYDROLOGY... A Flood Watch remains in effect for the entire area through 2 2am Wednesday. Showers and thunderstorms will continue this evening and tonight have the potential to produce torrential downpours with rainfall rates 1-2" an hour. It is quite possible for a spots to exceed 2" an hour at times in the heaviest activity. WPC has maintained a slight risk for excessive rain across the entire area highlighting the mainly localized flash flooding risk. A few of the quicker responding rivers, streams, and creeks nay experience flash flooding. A marginal risk of excessive rainfall remains in place for much of the area on Wednesday and Thursday with a continued localized flash flooding threat. && .TIDES/COASTAL FLOODING... The high rip current risk continues into early this evening. A moderate rip current risk has been forecast for Wed for all the ocean beaches due to incoming 3-4 ft/7-sec swell. It is possible that a short fused high risk may be needed for Wed afternoon at the Suffolk beaches if AM beach reports there come in on the high side. The moderate risk continues for all but the NYC beaches for Thu. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Heat Advisory until 8 PM EDT this evening for CTZ005>012. Air Quality Alert until 11 PM EDT this evening for CTZ005>012. Flood Watch until 2 AM EDT Wednesday for CTZ005>012. NY...Heat Advisory until 8 PM EDT this evening for NYZ067>075- 078>080-176>179. Air Quality Alert until 11 PM EDT this evening for NYZ078>081- 177-179. Flood Watch until 2 AM EDT Wednesday for NYZ067>075-078>081- 176>179. High Risk for Rip Currents until 8 PM EDT this evening for NYZ075- 080-081-178-179. NJ...Heat Advisory until 8 PM EDT this evening for NJZ002-004-006- 103>108. Flood Watch until 2 AM EDT Wednesday for NJZ002-004-006- 103>108. MARINE...Small Craft Advisory until 2 AM EDT Wednesday for ANZ350-353. && $$ SYNOPSIS...JP/BR NEAR TERM...JP SHORT TERM...JP LONG TERM...BR AVIATION...JMC MARINE...JP/BR HYDROLOGY...JP/BR TIDES/COASTAL FLOODING...BG