Marine Weather and Tide Forecast for West Yarmouth, MA

NEAR TERM /UNTIL 6 PM THIS EVENING/
Key Messages:

* Dry through today with mostly cloudy skies

Lingering showers over the southern waters from earlier this morning are expected to continue to dissipate. The influence of a maritime high pressure continues over southern New England today. Light east to ENE winds prevail, keeping the eastern coastlines cooler than the rest of the region as well. Cloudy skies continue as well, and highs will remain in the low 70s towards the interior and upper 60s across the rest of the region; spots along the east coast could dip into the low 60s, especially over the Cape and Islands.

SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/
Key Messages:

* Dry, cool overnight

* Slightly warmer for Monday

A weak shortwave will pass over the region Sunday night, but rain chances are expected to remain to our south. Generally, another dry night expected for southern New England. The maritime high's influence continues, keeping winds light and generally east to ESE over the region overnight. Lows expected to be cool once again, primarily sitting in the low to mid 50s. Some patchy fog may also develop in some parts of eastern MA into northern RI.

Highs begin to recover a bit Monday, but the cooler airmass aloft will keep temperatures still a bit lower than normal for mid June.
Deterministic guidance has 925 mb temperatures slightly increasing to around 15C, especially over the interior. Continued easterly winds will keep the eastern coastal areas cooler again, but highs may still reach the upper 60s/low 70s. Mid to upper 70s can be expected for the interior.

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
Key Messages:

* Warming trend kicks in midweek, peaking Thursday

* Mostly dry through much of the week aside from Thursday, which could see thunderstorms. Some could possibly turn severe.

* Less humid to end the week following cold frontal passage

Details...

Quiet night expected for Monday heading into Tuesday, with winds shifting more SE Tuesday. WNW flow aloft will begin to shift more SW Tuesday afternoon into Wednesday, which will aid in kick-starting the midweek warming trend. Timing is still slightly uncertain, but another wave looks to pass over the region sometime between Tuesday night and Wednesday that may bring some stray showers over western MA and CT. Chances still remain low and there is still variance between the guidance in the wave's track, but some measurable rain cannot be completely ruled out at this time.

The main threat for rain and thunderstorms comes Thursday ahead of a cold front expected to pass Thursday night into Friday. Continued SW flow will keep the region much warmer with highs approaching (and possibly exceeding) 90F in parts of southern New England. Ensembles have mean PWAT values ranging from 1.60" to 1.70" across the region heading into Thursday, and dew points are expected to be in the upper 60s to low 70s in the afternoon hours. With this environment, significant CAPE values are favored; the ECMWF ENS already has MUCAPE values well over 1000 J/kg for Thursday afternoon, and the other ensembles also have mean surface CAPE values approaching 1000 J/kg. Will be something to continue to monitor as Thursday gets closer.

Following the cold front's passage Thursday night, drier, less humid conditions make a return as dew points drop into the low 60s for Friday. Seasonably warm temperatures with breezier conditions move in heading into the weekend with the post-frontal airmass.

AVIATION /07Z SUNDAY THROUGH THURSDAY/
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

06z TAF Update:

Through Tonight...High confidence.

VFR for most with periodic MVFR over the Islands as scattered showers continue to linger across the southern waters. Light to calm winds primarily from the NE.

Sunday...Moderate Confidence in timing.

MVFR/VFR. MVFR conditions expected primarily across the south coast and the Cape/Islands. Dry with light NE to ENE winds.
Winds will begin to shift more ESE in the afternoon heading into the evening hours.

Sunday Night...Moderate Confidence.

VFR with possible MVFR to IFR cigs over the south coast and Cape/Islands. Vsby reductions possible across eastern MA terminals around 06z. Light ESE winds. Dry conditions expected.

KBOS Terminal...Moderate confidence in MVFR timing.

Lower confidence in timing for vsby reductions tomorrow night.
Otherwise, high confidence for rest of TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Monday Night through Thursday/...

Monday Night: Mainly VFR, with local MVFR possible.

Tuesday: Mainly VFR, with areas MVFR possible.

Tuesday Night: Mainly VFR, with areas IFR possible. Slight chance SHRA.

Wednesday: Mainly VFR, with local IFR possible. Slight chance SHRA.

Wednesday Night: VFR. Slight chance SHRA.

Juneteenth: VFR. Breezy. Chance SHRA, chance TSRA.

MARINE
Forecaster Confidence Levels:

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

Today through Monday...

Seas continue to trend down to 2-4 ft with ENE winds at or below 15 kts. These calmer seas are expected to continue through Monday. Winds remain below 10 kts over the eastern waters.
Winds pick back up during the day Monday with sustained winds up to 15 kts possible once more.

Outlook /Monday Night through Thursday/...

Monday Night through Tuesday: Winds less than 25 kt.

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

Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers.

Wednesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers.

Juneteenth: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Slight chance of rain showers, slight chance of thunderstorms.

BOX WATCHES/WARNINGS/ADVISORIES
CT...None.
MA...None.
RI...None.
MARINE...None.