Long Island Sound East of New Haven CT/Port Jefferson NY Marine Forecast
| This Afternoon...Sw Winds Around 5 Kt. Seas 1 Ft Or Less. Slight Chance Of Showers. |
| Tonight...Sw Winds Around 5 Kt, Becoming N After Midnight. Seas 1 Ft Or Less. |
| Mon...E Winds Around 5 Kt, Becoming Se In The Afternoon. Seas 1 Ft Or Less. Wave Detail: Se 1 Ft At 2 Seconds. Showers Likely With Slight Chance Of Tstms In The Afternoon. |
| Mon Night...S Winds 10 To 15 Kt With Gusts Up To 25 Kt. Seas 1 Ft Or Less, Then Around 2 Ft After Midnight. Wave Detail: Se 1 Ft At 2 Seconds, Becoming S 1 Ft At 3 Seconds. Showers And Slight Chance Of Tstms In The Evening, Then Showers And Chance Of Tstms After Midnight. |
| Tue...W Winds 5 To 10 Kt, Becoming Nw In The Afternoon. Seas 1 Ft Or Less. Wave Detail: Sw 1 Ft At 3 Seconds. Showers. |
| Tue Night...Nw Winds 5 To 10 Kt. Seas 1 Ft Or Less. |
| Wed...W Winds 5 To 10 Kt. Seas 1 Ft Or Less. |
| Wed Night...W Winds Around 5 Kt. Seas 1 Ft Or Less. |
| Thu...Sw Winds 5 To 10 Kt. Seas 1 Ft Or Less. |
| Thu Night...S Winds 5 To 10 Kt. Seas 1 Ft Or Less. Chance Of Showers. Winds And Seas May Be Higher In And Near Tstms. |
| Area Forecast Discussion National Weather Service New York NY 829pm EDT Sunday Jun 21 2026 .WHAT HAS CHANGED... While overall rainfall totals have decreased slightly, high hourly rates are still possible Monday afternoon into Monday night. There is still potential for isolated flash flooding. Portions of northeast NJ and NYC are now in a slight risk (level 2/5) of severe thunderstorms for Monday afternoon and evening. Small Craft Advisory issued for the ocean waters, the NY Harbor and the South Shore Bays. High Risk for Rip Currents issued for the ocean beaches of NYC, Nassau and western Suffolk .KEY MESSAGES... 1) Isolated late day showers and a rumble of thunder possible, mainly across the interior. 2) Heavy showers and thunderstorms Monday afternoon and night will bring the potential of urban and poor drainage flood impacts, as well as localized flash flooding. A severe thunderstorm can also not be ruled out. 3) Showers and thunderstorms are possible again Thursday and Friday. 4) A high rip current risk expected for late day Monday for the ocean beaches of NYC, Nassau and western Suffolk, and may be ongoing at all the ocean beaches into part of Tuesday morning. See Marine section for details. .KEY MESSAGE 1... The passage of a shortwave this afternoon along with some surface convergence along sea breezes and a surface trough may develop isolated shower activity. Instability is very shallow, but there is decent agreement in a few hundred J/kg of CAPE between -10 and -20 C to support a few lightning strikes (with the exception of the HRRR (High-Resolution Rapid Refresh) which appears to be over mixing). Dry sub-cloud layer also supports locally gusty winds in any of the isolated showers. Any shower development this afternoon will quickly dissipate this evening as the shortwave energy passes to the east. .KEY MESSAGE 2... Low pressure over the Mississippi Valley will continue to move east toward our area this evening. At the same time, an associated warm front will approach from the south and linger over or near the area before the low pulls a cold front through early Tuesday morning. This system will pull up tropical moisture from the south with guidance consistently showing PW around 2 inches. This combination brings the threat for potential heavy showers and thunderstorms Monday afternoon through Monday night. Latest guidance continues to struggle on placement of the warm front as well as heaviest axis of precipitation. However, CAM's have started hinting at more widespread higher totals being farther north across the Lower Hudson Valley and southern CT. This can be seen in the 12Z HREF LPMM with a few stripes of 1.5-2.0 inches in these areas. Given this environment, any shower or thunderstorm that does develop will have the potential to put down high hourly rates, mainly up to 1.0-1.5 inch/hr, but upwards to 2 inches in one hour can not be ruled out. This can be seen in the 12Z Hi-res guidance on the WPC URRD with a few members showing just under 2 inches in one hour. Confidence is still too low at this time for the issuance of a Flood Watch. While these higher rates do cause concern for urban areas, if they occur elsewhere they will likely not cause flash flooding due to how dry we have been. There is too much uncertainty in coverage and location. Additionally, several area river and streams are running well below normal, toward their 10th percentile. This helps lower the risk for river and stream flooding. Guidance will have to continue to be monitored over the next 24 hours as a Flood Watch can not be completely ruled out. Additionally, while confidence is still relatively low, there is potential for some of these thunderstorms to become severe. This is mainly due to the potential location of the warm front and decent low level curvature in model hodographs. The main threats will be damaging wind gusts and an isolated tornado. The Storm Prediction Center has nudged a slight risk of severe thunderstorms into Staten Island and Union County in NE NJ, and a 2% tornado risk into all of NE NJ and NYC. Except for far eastern Long Island and SE CT, the rest of the area is under a marginal svr risk. .KEY MESSAGE 3... Southwest flow aloft looks to set up by late Thursday into Friday ahead of the next shortwave/cold front. This would help to trigger the potential for showers and a few thunderstorms. Confidence is starting to increase that the greatest potential ends up on Friday when the shortwave axis is currently forecast to move across the area. Any severe/hydro impacts are uncertain at this time since this is 5-6 days out. Marine A southerly flow will strengthen as low pressure approaches from the west. All waters except the Sound and Peconic/Gardiners Bays are now under a Small Craft Advisory from late Monday through Monday night. This is due to 25-30 kt gusts and 5-ft seas for the ocean waters. There is potential for the other waters to be added in subsequent forecasts. Thereafter, winds and seas should remain below SCA (Small Craft Advisory) criteria. Rip Currents The rip current risk for the rest of today is moderate at the Suffolk beaches, where a 3-ft S swell @ 7 seconds persists. On Monday, the rip current risk will be moderate for much of the day, then increase to high after 5pm at the ocean beaches of NYC, Nassau and western Suffolk as S flow increases to 20 kt and associated wind waves build to 4-5 ft, at a time when lifeguards and beach patrols will be coming off duty. RCMOS forecast followed for the most part as it is well aligned with the trend in winds/seas. The high risk will expand to all ocean beaches Monday night, and may still be ongoing into part of Tuesday morning especially at the Suffolk beaches, as residual 3-4 ft wind waves continue with winds still partly onshore. Otherwise, a mostly moderate risk expected for Tuesday as winds turn offshore and seas slowly subside. NOAA New York NY Office: Watches - Warnings - Advisories CT...None. NY...High Risk for Rip Currents from Monday afternoon through Monday evening for NYZ075-080-178-179. NJ...None. Marine Small Craft Advisory from 2pm Monday to 6am EDT Tuesday for ANZ338-355. Small Craft Advisory from 6pm Monday to 6am EDT Tuesday for ANZ345-350-353. |
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