Marine Weather Net

Cape Cod Bay Marine Forecast


5 - 10




5 - 10


5 - 10

The Marine Weather Forecast In Detail:
ANZ231 Forecast Issued: 701 PM EDT Wed Apr 17 2024

Tonight...Se Winds 5 To 10 Kt. Seas Around 2 Ft This Evening, Then 1 Foot Or Less. Wave Detail: N 1 Ft At 3 Seconds And E 1 Ft At 3 Seconds, Becoming Nw 1 Ft At 3 Seconds And E 1 Ft At 4 Seconds.
Thu...E Winds Around 10 Kt. Seas 1 Foot Or Less, Then Around 2 Ft In The Afternoon. Wave Detail: E 1 Ft At 3 Seconds And Se 1 Ft At 8 Seconds, Becoming E 1 Ft At 2 Seconds And Se 1 Ft At 7 Seconds.
Thu Night...E Winds 5 To 10 Kt. Seas Around 2 Ft. Wave Detail: E 1 Ft At 3 Seconds And Se 1 Ft At 7 Seconds.
Fri...Se Winds 5 To 10 Kt. Seas Around 2 Ft. Wave Detail: Se 2 Ft At 6 Seconds And E 1 Ft At 3 Seconds.
Fri Night And Sat...Sw Winds Around 10 Kt. Seas Around 2 Ft. Wave Detail: S 2 Ft At 4 Seconds And Se 1 Ft At 3 Seconds. A Chance Of Showers Through The Day.
Sat Night...W Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas Around 2 Ft. Wave Detail: W 2 Ft At 3 Seconds And Se 1 Ft At 6 Seconds.
Sun Through Mon Night...S Winds 10 To 15 Kt With Gusts Up To 20 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
935pm EDT Wednesday April 17 2024

Increasing cloud coverage this afternoon, rain chances increase during the overnight hours mainly across western Massachusetts and northern Connecticut. Cloudy, much cooler, with scattered light rain continuing for Thursday. Dry and seasonable for much of Friday with high pressure in control. A cold front brings another round of light rain showers Friday night into Saturday morning. Dry for the rest of Saturday with gusty winds. The dry stretch of weather continues into early next week with the next chance of wet weather Tuesday night and Wednesday as a frontal system approaches.

Near Term - Until 6am Thursday Morning
935 PM

* Showers mainly southwest of an ORE-PVD-ORH line overnight * Low temps in the lower to middle 40s

Previous forecast is on track. 850 MB warm front will generally remain across southwest MA & CT overnight with a mid level ridge axis blocking its eastward progress. This will confine most of the showers to the southwest of an ORE-ORH-PVD line overnight. To the east of this region...nothing more than perhaps a few brief light showers/sprinkles with the majority of the overnight hours featuring dry weather. The clouds will keep low temps mainly in the lower to middle 40s.

Short Term - 6am Thursday Morning Through Thursday Night

* An easterly wind will lead to a much cooler day, a few showers are possible, though a washout is not expected.

Mid-level ridge for Thursday, though a shortwave passage will bring our a few showers, not a washout by any means. At this point, kept POPs around 30 ~ Chance Rain. The more noticeable difference is the east wind, allowing for a raw/cool feel. High temperatures along the immediate coast are in the middle to upper 40s. Elsewhere, highs are lower and middle 502. Higher elevations in western Massachusetts are the coldest in the lower 40s.

East wind are 10 to 15 mph, with gusts along the coast to 25 mph.

Precipitation chances come to an end overnight, though clouds and on shore flow does continue into the overnight hours. Do think spots along the eastern coast could see spot drizzle, but didn't have the confidence to include it in the WX GRID. Guidance this afternoon remained split on how much low level moisture would linger, so OPT to leave it out. Similar to the night before, our temperatures are in the upper 30s and low 40s.

Long Term - Friday Through Wednesday
Key Points... * Mainly dry and seasonable Friday

* Scattered showers Fri night into early Sat followed by mild and breezy conditions Sat afternoon

* Dry conditions return for Sunday into Tue. Cooler Sun, then milder Monday and Tuesday

* Shower chances increase by Wed

Details... Friday into Saturday... Mid level shortwave departs by early Fri with weak shortwave ridging following. This will bring dry conditions for much of the day, although next shortwave and cold front will be approaching from western NY in the afternoon. We should see some sunshine develop, especially in eastern New England but trend will be for increasing cloud cover in the afternoon. Low risk a few showers could spill into western MA by days end but bulk of shower activity should hold off until Fri night. Near normal temps Fri.

Weak cold front moves into SNE Fri night with modest increase in moisture as PWATs (Precipitable Waters) increase to near 1" ahead of the front. This should bring a round of scattered showers Fri night which will likely linger into Sat morning, especially in the east as the front gets hung up near the coast. Then drying out in the afternoon with somewhat gusty W winds developing in the afternoon. Given the colder airmass will be lagging to the NW assocd with a secondary cold front, it should be a mild afternoon with temps reaching the 60s, and some upper 60s possible in SE MA.

This secondary cold front is tied to a decent shortwave passage late Sat-Sat evening. The column is drying at this time but there may be a brief window for a few showers with the front late Sat in the interior. Did not include in the forecast at this time as confidence is low, but will re-evaluate in later forecasts.

Sunday through Wednesday... Cooler post-frontal airmass settles in on Sunday with seasonable temps and abundant sunshine. Dry weather continues Monday and Tuesday with moderating temps. A potent shortwave is forecast to move off the mid Atlantic coast Monday night-Tuesday but global ensemble guidance keeps moisture well to the south with a minimum in PWATs (Precipitable Waters) across SNE. Next northern stream shortwave approaches from the west Tuesday night and Wed. Timing and amplitude of the system is uncertain but risk for showers will increase by Wed.

Forecaster Confidence Levels:

Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent.

Tonight through Thursday Night...High Confidence.

* Small Craft Advisory for Block Island Sounds and waters south of Block Island tonight and into Thursday.

A weak wave of low pressure drops southeast across the mid- Atlantic with high pressure moving across the eastern Canadian Maritimes into Thursday. A few spot showers and perhaps a rumble of thunder possible. This will result in SE winds this evening shifting to the E by Thursday morning at speeds of 10 to 15 knots. Some gusts up to 25 knots with marginal 5 foot seas for the southwest waters, hence the newly issued Small Craft Advisory through much of Thursday. Seas may remain elevated enough to warrant the advisory to be extended into Thursday night for the waters south of Block Island. Future forecasts may want to include this.

Outlook /Friday through Monday/... Friday: Winds less than 25 kt. Seas locally approaching 5 ft.
Friday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers.
Saturday: Winds less than 25 kt. Chance of rain showers.
Saturday Night: Winds less than 25 kt. Seas locally approaching 5 ft.

Sunday through Monday: Winds less than 25 kt.

NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None.

Small Craft Advisory from 5am to 5pm EDT Thursday for ANZ237. Small Craft Advisory from 5am to 8pm EDT Thursday for ANZ256.