Marine Weather Net

Cape Cod Bay Marine Forecast


OVERNIGHT

E
WINDS
10
KNOTS

SUN

E
WINDS
5 - 10
KNOTS

SUN NIGHT

E
WINDS
5 - 10
KNOTS

MON

SE
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
ANZ231 Forecast Issued: 1006 PM EDT Sat Jun 14 2025

Overnight...E Winds Around 10 Kt. Seas Around 2 Ft. Wave Detail: E 1 Foot At 3 Seconds And Se 1 Foot At 8 Seconds.
Sun...E Winds 5 To 10 Kt. Seas Around 2 Ft. Wave Detail: E 1 Foot At 3 Seconds And Se 1 Foot At 9 Seconds.
Sun Night...E Winds 5 To 10 Kt. Seas Around 2 Ft. Wave Detail: E 2 Ft At 2 Seconds And S 1 Foot At 7 Seconds.
Mon...Se Winds 5 To 10 Kt. Seas Around 2 Ft. Wave Detail: E 2 Ft At 2 Seconds And S 1 Foot At 7 Seconds.
Mon Night And Tue...Se Winds 5 To 10 Kt. Seas Around 2 Ft. Wave Detail: Se 2 Ft At 5 Seconds.
Tue Night...S Winds 5 To 10 Kt. Seas Around 2 Ft In The Evening, Then 1 Foot Or Less. Wave Detail: Se 2 Ft At 5 Seconds, Becoming S 1 Foot At 3 Seconds And Se 1 Foot At 7 Seconds.
Wed And Wed Night...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas Around 2 Ft.
Thu And Thu Night...Sw Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 2 To 4 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
731pm EDT Sat Jun 14 2025

Synopsis
Dry weather overspreads the region tonight, as high pressure builds into the area. Maritime high provides dry but cool temperatures Sunday, along with mostly cloudy conditions. Cool weather lingers into Monday, followed by a warming trend, with heat and humidity peaking Thursday, highs 85-90. Mainly dry weather next week, except Thu, with the risk of thunderstorms ahead of an approaching cold front.

Near Term - Until 6am Sunday Morning
Key Messages:

* Lingering showers push offshore this evening

* Cloudy, overnight temps in the mid 50s

Today:

A few showers across RI, South Coast, Cape and Islands linger through the early evening as a surface high pressure sits over our southern waters. Light NE winds remain through the night as onshore flow continues. Predominately cloudy skies as temperatures drop into the low to mid 50s overnight.

Short Term - 6am Sunday Morning Through Sunday Night
Key Messages:

* Drier, but still cool for Sunday

Dry conditions are expected Sunday while still under the influence of the surface high. It will be another cool day, especially along the east coast, with cool temperatures aloft and partly cloudy skies. Sunday's temps in the mid 60s across the eastern coast, Cape and Islands, and upper 60s to low 70s for the interior. A weak wave moves across Sunday night, keeping shower chances confined to the southern waters.

Long Term - Monday Through Saturday

235 PM

Key Points

* Seasonably cool Mon, then a warming trend Tuesday & Wednesday w/heat & humidity peaking Thu (85-90). More comfortable Fri & next Sat

* Dry weather much of next week, except Thu, chance of thunderstorms (possibly severe) with approaching cold front

Temperatures...robust northern stream across southeast Canada yields WNW flow over New England early next week, suppressing frontal boundary south of the region. This yields cool maritime high into New England. Very comfortable conditions to begin the week Monday, with highs in the 70s (near 80 in the CT River Valley). Dew pts in the 50s will yield comfortable humidity and overnight temps. By Tue, mid/upper flow becomes more SW, supporting a warming trend with heat and humidity peaking Thu. Highs surging to 85-90 and dew pts in the low 70s, definitely a true summer/warm sector airmass! EC & CMC ensembles support 20-40% probs of 90+ away from the south coast, while the GEFS indicate up to 50-60% probs! FROPA sometime late Thu/Thu night yields more comfortable conditions Friday (highs 80- 85, with dew pts in the 50s and 60s), possibly lingering into next Sat. That would be quite the switch from previous Saturdays.

Precipitation...mainly a dry week ahead (discounting the somewhat wet NAM Monday & Tue) with the main risk of precipitation being Thursday, with potential thunderstorms ahead of a FROPA. In fact, taking a closer look, ensembles offer impressive shear/cape setup, with 40-45 kt of 500 mb flow across New England, fairly strong for late June. Also, with highs 85-90 combined with dew pts in the low 70s, robust capes will develop ahead of the front. Machine learning (ML) probs from NSSL guidance for severe weather are fairly high for a day 6 forecast. Something to watch as we approach Thu.

Marine
Forecaster Confidence Levels:

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

730 PMexpanded SCA (Small Craft Advisory) across all RI and southern MA waters, as ENE winds 15-20G25 kt becoming more common across these waters, as low level jet moves across this area. Winds slacken 03z-06z, as wave of low pressure south of New England exits out to sea and maritime high builds into SNE. Earlier discussion below.

---------------------------------------------------------

Tonight through Sunday night... SCA (Small Craft Advisory) is effect across the southern waters with ENE winds around 25 kts and brief 3-5 ft seas. Seas and winds trend downward into early Sunday morning.

Outlook /Monday through Thursday/... Monday: Winds less than 25 kt. Seas locally approaching 5 ft.
Monday Night through Tuesday: Winds less than 25 kt.

Tuesday Night through Wednesday: Winds less than 25 kt. Slight chance of rain showers.
Wednesday Night: Winds less than 25 kt.

Juneteenth: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas locally 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 until 2am EDT Sunday for ANZ232>235-237- 254>256.