Long Island Sound East of New Haven CT/Port Jefferson NY Marine Forecast
| Today...Nw Winds Around 5 Kt, Becoming Sw Around 5 Kt This Afternoon. Seas 1 Ft Or Less. |
| Tonight...S Winds 5 To 10 Kt. Seas 1 Ft Or Less. Wave Detail: Sw 1 Ft At 2 Seconds. |
| Thu...S Winds 5 To 10 Kt, Increasing To 10 To 15 Kt With Gusts Up To 20 Kt In The Afternoon. Seas 1 Ft Or Less, Then Around 2 Ft In The Afternoon. Wave Detail: S 1 Ft At 2 Seconds, Becoming S 1 Ft At 3 Seconds. Slight Chance Of Showers And Tstms In The Afternoon. |
| Thu Night...S Winds 10 To 15 Kt With Gusts Up To 20 Kt, Diminishing To 5 To 10 Kt After Midnight. Seas Around 2 Ft In The Evening, Then 1 Ft Or Less. Wave Detail: S 1 Ft At 3 Seconds, Becoming Sw 1 Ft At 3 Seconds. Chance Of Showers And Slight Chance Of Tstms. |
| Fri...Sw Winds Around 5 Kt. Seas 1 Ft Or Less. Chance Of Showers In The Morning, Then Slight Chance Of Showers And Tstms In The Afternoon. |
| Fri Night...W Winds Around 5 Kt, Becoming N After Midnight. Seas 1 Ft Or Less. |
| Sat...Ne Winds 5 To 10 Kt. Seas 1 Ft Or Less. |
| Sat Night...S Winds Around 5 Kt. Seas 1 Ft Or Less. |
| Sun...Sw Winds 5 To 10 Kt. Seas 1 Ft Or Less. |
| Sun Night...Sw Winds 5 To 10 Kt. Seas 1 Ft Or Less. Winds And Seas May Be Higher In And Near Tstms. |
| Area Forecast Discussion National Weather Service New York NY 1038pm EDT Wednesday August 26 2026 .WHAT HAS CHANGED... A Flood Watch has been issued for Thursday between Noon and 11 PM for the Lower Hudson Valley, NE NJ, NYC, Nassau county and Fairfield county. .KEY MESSAGES... 1) Confidence is increasing in a period of heavy rainfall and scattered thunderstorms Thursday into Thursday night. Isolated to scattered instances of flash flooding and strong to severe thunderstorms are possible for parts of the area. 2) Dry and seasonable for the weekend ahead, with a warming trend early next week. 3) High risk for rip currents on Thursday. .KEY MESSAGE 1... Mid level open trough approaches the northeast early Thursday, weakening as it does so. Surface low pressure with a slowly moving frontal system accompanies this feature, and approaches the local area by Thursday morning. A warm front nears the region by early Thursday, with surface low pressure well to the northwest. Southerly flow will begin to increase this afternoon, with moisture advection commencing ahead of this system and surface dewpoints reaching the low 70s by Thursday morning. PWATs (Precipitable Waters) peak around 1.6-1.8" to just over 2" (depending on which guidance you look at)by Thursday afternoon and evening, which nears the max average for 8/27 per SPC's sounding climatology. Precipitation chances will increase through the day on Thursday as the warm front approaches and lifts to our north. Heaviest precipitation, and thus threat for any flash flooding, looks to occur Thursday afternoon and evening along a pre-frontal trough that sets up along or northwest of the I-95 corridor. Most 12Z CAMs show an axis of precipitation setting up SW to NE somewhere near NYC in the afternoon, but CAMs vary in coverage. Following this, by late afternoon and evening a second axis of precipitation will set up well N & W of NYC then traverse east, losing intensity the farther east it traverses. Areawide amounts should be around 0.5" to 1.5". Its very possible areas far to the east receive very little, if any, rainfall. The areas of highest rainfall amounts and thus highest rainfall rates and greatest risk for flash flooding somewhat remains uncertain. 12Z CAMs vary on where the heaviest axis of precipitation will set up. Some bring the heaviest precipitation over the LoHud and possibly NE NJ, others over NYC, Westchester, Nassau, and Fairfield. Given uncertainty in exact axis of highest precip, the 12Z HREF shows a 25km neighborhood probability of exceeding 1"/hr rainfall rates of 50 to 90% across NYC, NE NJ, Nassau, Fairfield, and LoHud. The 12Z REFS appears to highlight similar areas for the highest rainfall rate potential. However, given recent rainfall lowering FFG and high enough confidence in higher rainfall rates occurring, have gone with a Flood Watch for these areas. Flash flooding is not anticipated to be widespread in all areas of the watch, but confidence is high enough in the conditions for it to occur in any area of the watch. Future CAM output will need to be monitored for better agreement in the heaviest rainfall location, so this can be better messaged. WPC has expanded their Slight Risk (2/4) of excessive rainfall which now includes all of LoHud and most of NE NJ, just scraping NYC. Finally, thunderstorm chances also increase by Thursday afternoon with model soundings showing both decent instability (~1500-2500 J/kg MLCAPE) and some shear, so cannot rule out isolated to scattered severe thunderstorms. Wind gusts would be the main hazard associated with the strongest storms, with DCAPE forecast to be in the 500-1000 J/kg. Storm Prediction Center maintains the marginal risk of severe thunderstorms over NYC, but has expanded the SLight Risk (2/5) for severe thunderstorms for areas N & W of NYC and has expanded the Marginal (1/5) risk to include Fairfield and Nassau counties. An isolated tornado or two can not be ruled out for areas N & W of NYC. 12Z CAMs bring SigTor Parameters between 1 to 2 for areas of the LoHud given decent shear and helicity values. Storm Prediction Center expanded a Slight (2/5) Risk for Severe Weather across western portions of the area, becoming Marginal (1/5) for NYC, Nassau, and Fairfield. Instability rapidly drops by Thursday night with a quick end to showers and thunderstorms. .KEY MESSAGE 2... Mainly zonal flow behind the late week system turns into weak ridging by late Saturday into Sunday as heigheights aloft rise. Any leftover shower activity from Friday should be well offshore by early Saturday morning behind the frontal passage. Skies will clear with northerly flow on Saturday, and dry conditions lasting into Sunday. Winds turn southerly on Sunday as the surface high shifts offshore, and dewpoints climb a few degrees relative to Saturday. Otherwise, near to slightly below normal temperatures both days, with highs in the upper 70s to lower 80s. Heigheights continue to build into early next week, with increasing temperatures. .KEY MESSAGE 3... Winds increase on Thursday out of the S closer to 15-20 kt. This combined with a building swell of 3-4ft at 5s out of the S/SE will bring a high risk of rip currents. The risk through much of the day may end up being moderate for southeast Suffolk, but high is possible by the late afternoon/evening. Marine Sub small craft conditions are expected through the week. Southerly flow increases late Wednesday night into Thursday, with ocean seas getting to around 4 ft and gusts approaching 20 kt. Otherwise, sub advisory conditions prevail with seas and winds diminishing for the weekend with a light pressure gradient with high pressure building across for the weekend. Rip Currents A moderate risk continues today with a weak swell component and around 10-15 kt S/SW winds. Winds increase on Thursday out of the S closer to 15-20 kt. This combined with a building swell of 3-4ft at 5s out of the S/SE will bring a high risk of rip currents. The risk through much of the day may end up being moderate for southeast Suffolk, but high is possible by the late afternoon/evening. The risk lowers back to moderate on Friday with a lingering 3ft 6s swell out of the SE. NOAA New York NY Office: Watches - Warnings - Advisories CT...Flood Watch from Thursday afternoon through Thursday evening for CTZ005-009. NY...Flood Watch from Thursday afternoon through Thursday evening for NYZ067>075-176>179. High Risk for Rip Currents from 6am EDT Thursday through Thursday evening for NYZ075-080-081-178-179. NJ...Flood Watch from Thursday afternoon through Thursday evening for NJZ002-004-006-103>108. Marine None. |
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