Cape Cod Bay Alt Marine Forecast
| Today...Se Winds 5 To 10 Kt. Seas Around 2 Ft. Wave Detail: Se 1 Foot At 3 Seconds And Se 1 Foot At 8 Seconds. |
| Tonight...Se Winds 5 To 10 Kt. Seas Around 2 Ft. Wave Detail: Se 1 Foot At 2 Seconds And Se 1 Foot At 8 Seconds. A Chance Of Showers. Vsby 1 To 3 Nm After Midnight. |
| Thu...Se Winds 5 To 10 Kt. Seas Around 2 Ft. Wave Detail: S 2 Ft At 8 Seconds And Se 1 Foot At 2 Seconds. A Chance Of Showers. Vsby 1 Nm Or Less, Increasing To 1 To 3 Nm In The Afternoon. |
| Thu Night...S Winds Around 5 Kt. Seas Around 2 Ft. Wave Detail: Se 2 Ft At 8 Seconds And Se 1 Foot At 3 Seconds. |
| Fri...Sw Winds Around 5 Kt, Becoming Se In The Afternoon. Seas 1 Foot Or Less. Wave Detail: E 1 Foot At 4 Seconds And Se 1 Foot At 8 Seconds. |
| Fri Night...S Winds Around 5 Kt. Seas 1 Foot Or Less. Wave Detail: Se 1 Foot At 2 Seconds And Se 1 Foot At 8 Seconds. A Chance Of Showers. |
| Sat And Sat Night...S Winds 5 To 10 Kt. Seas Around 2 Ft. A Chance Of Showers. |
| Sun And Sun Night...W Winds 5 To 10 Kt. Seas Around 2 Ft. Seas Are Reported As Significant Wave Height, Which Is The Average Of The Highest Third Of The Waves. Individual Wave Heights May Be More Than Twice The Significant Wave Height. |
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Area Forecast Discussion National Weather Service Boston/Norton MA 701am EDT Wednesday May 14 2025 Synopsis Scattered showers and perhaps a few thunderstorms will be possible at times for the second half of this week...but not expecting a washout with the greatest risk for activity tonight into early Thursday, and again around Friday and/or Saturday. Temperatures to start next week turn cooler following the passage of a cold front, and humidity decreases as drier air moves in with it. Near Term - Through Tonight 300am Update: Key Messages: * Increasing cloud cover towards overcast today. * Mostly dry during the morning, but risk for showers increases late morning to mid afternoon from west to east. Washouts not expected. * Still rather mild temps in the lower to mid 70s, but cooler along the coast and in western New England. Details: Gradual deterioration in conditions expected today with increasing cloudiness and a gradual north/east expansion of the existing rain shield over SW CT. Recent trends have offered a later onset timing of these light rain showers even into western New England, and it may not really develop until late morning/noontime for the vast majority of locations in western MA/CT, and not until mid afternoon for most of central and eastern MA and RI. Overall not looking like a washout today in most areas. The later arrival of rain showers allowing for a little longer period of sun in eastern MA away from the coast should allow temps to rise into the mid 70s, but quite a bit cooler near the coasts in the lower to mid 60s. In CT and western MA, slow rises in temps due to overcast should keep temps in the mid to upper 60s. Short Term - Thursday 300am Update: Key Messages: * Periods of showers, even a rumble or two of thunder tonight to early Thurs AM. Best chance interior SNE. * Rather humid with more clouds than sun on Thurs, with hit- or-miss showers possible at times. Details: Tonight: Approach of deamplifying shortwave trough energy over the OH Valley will allow for an increased SSE low-level jet to develop tonight as a warm front moves thru. This will transport increasing precipitable water values/higher dewpoints along with a burst of weak elevated instability rooted above near-surface stable layer (Showalter indices around 0 to -1, with CAPE values ranging from 300-700 J/kg using a most-unstable parcel approach). Expect showers to increase in coverage tonight in the interior, then spread ENE into RI and eastern MA toward daybreak. Given the weak elevated instability, included a mention of isolated thunder but severe weather isn't expected. It would be more of the isolated lightning strike type of mention. Rain amts could be up to a quarter- inch in some spots, but most areas stay below that, with lesser rain totals as one moves north. Should be a rather mild night and a touch humid too, with temps in the mid to upper 50s, maybe staying near 60 out in the CT Valley. Thursday: Warm front then moves offshore early-morning on Thurs, putting much of Southern New England in a cloudy warm-sector which is also rather humid by mid-May standards (e.g. dewpoints in the lower 60s). Wouldn't rule out intermittent, slow-moving showers in this warm sector, and although convective temps are pretty low, there isn't really much to hang on to as far as sources of lift go. Given this I couldn't show Probability of Precipitation any higher than slight/lower Chance. Thinking there will end up being several hours of dry weather, but there will also be some showers to dodge at times. How warm temps may get is contingent on breaks in the cloudiness; I kept temps mainly in the 60s to low 70s under mostly cloudy conditions but potential for quite a bit warmer (well into the 70s) if we do get any sustained breaks in cloud cover. Long Term - Thursday Night Through Tuesday Key Messages: * Unsettled conditions late this week into the start of the weekend, including a low risk for thunderstorms Friday and Saturday * Temperatures decrease late in the weekend into early next week Details... Guidance continues to agree on the overall pattern late this week into the weekend. Drier conditions return Thursday night ahead of our next chance for showers and storms. A low moving across southern Canada will continue to move east and will eject shortwave energy eastward into the northeast US, which may assist in creating a more favorable environment for some storms. The chance that some could turn severe at this time still remains low, and what does develop is more likely to be quite scattered versus being a widespread event. Ensembles are continuing to hint at some elevated CAPE values Friday into Saturday, with SREF probs for surface CAPE at 500 J/kg or higher ranging from 70 to 90 percent across western and central MA. Some lower probs Friday exist for MLCAPE values at or above 1000 J/kg across this same area, reaching up to 30 percent. The highest chances for severe weather, though, still remain to our southwest. This will continue to be monitored as we get closer to the weekend. A cold front moves through Sunday which is expected to usher in a drier airmass following the exit of the mid-level low. Winds shift more to the NW and ridging begins to push into the region to start next week. 925 mb temperatures cool from around +20C over Friday and Saturday closer to +5C and +10C by Monday, continuing into Tuesday. Highs Friday are expected to be in the upper 70s and even into the low 80s for most, aside from the Cape and Islands where southerly winds moving over the Atlantic will bring highs down to the low 70s and upper 60s. Saturday and Sunday highs are expected to be similar; primarily in the 70s. Once the cold front moves through, highs to start the week may settle more into the mid to upper 60s. Marine Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Today through Thursday...High Confidence. Winds will remain below SCA (Small Craft Advisory) criterion through the period. However waves will be building to around 4-6 ft over the southern offshore waters starting later today and into Thursday. SCAs (Small Craft Advisories) remain posted due to the building seas. Areas of mist/fog and showers develop tonight and into early Thursday. Outlook /Thursday Night through Sunday/... Thursday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Friday: Winds less than 25 kt. Seas locally approaching 5 ft. Friday Night through Saturday: Winds less than 25 kt. Chance of rain showers, isolated thunderstorms. Saturday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers. Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers. NOAA Boston MA Office: Watches - Warnings - Advisories CT...None. MA...None. RI...None. Marine Small Craft Advisory from 6pm this evening to 8pm EDT Thursday for ANZ255-256. |
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