Marine Weather and Tide Forecast for Sagamore, MA

NEAR TERM /UNTIL 6 AM FRIDAY MORNING/
Key Messages

* Chilly tonight with low temps near or below freezing for portions of eastern MA and interior Northwest MA. Elsewhere lows in the mid to upper 30s.

Tonight

High pressure builds over southern New England this evening and overnight. This will relax the pressure gradient and bring an end to the gusty northwest winds from this afternoon. With a bone dry air mass, we can expect very efficient radiational cooling. Thus, leaned toward the lower end of guidance for low temps tonight which yielded below freezing overnight temps at a few locations in eastern MA, interior/northwest MA, and western CT. Elsewhere, low temps in the mid to upper 30s will be more common with perhaps a few locations along the immediate coast in the low 40s.

SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/
Key Messages:

* Pleasant spring Friday with high temps in the mid to upper 60s, cooler for Cape/South Coast

* Gusty southwest winds tomorrow from 20 to 30 mph with low RH 20-30 percent may support elevated fire weather potential

Friday and Friday Night

High pressure shifts east during the first half of the day tomorrow.
As this occurs an upper-low deepening over northern Quebec will help strengthen the pressure gradient over southern New England. As a result, we are likely to experience increasing southwesterly winds during the day tomorrow. Some gusts from 20 to 30 mph will be possible in what should be a well mixed boundary layer. Temperatures will be substantially warmer tomorrow afternoon as low-level southwest flow will advect 925 hPa temps near 10 Celsius over the region. Expect highs in the mid to upper 60s for most of southern New England. The exception locations will be The Cape, Islands, and South Coast where southwest flow off the cooler Atlantic waters will suppress high temperatures to the mid to upper 50s.

Tomorrow night, southwest flow begins to advect more moisture over the region with PWATs rising to 1-1.25" over southern New England.
A weak-short wave aloft will traverse over northern New England tomorrow night as well. This may support a few spot showers for a few locations across northeastern MA. Confidence is shower activity is low at this time, but HRRR guidance gives less than a 20% chance for measurable precipitation over Middlesex, Essex, and Suffolk Counties in MA. Can't rule out a rumble of thunder with any showers that develop as there will be some instability in the upper atmosphere with steep mid-level lapse rates aloft.

LONG TERM /SATURDAY THROUGH THURSDAY/
Key Messages:

* Warm and rather breezy Saturday with a few showers Saturday Night * Breezy again Sunday * Unsettled weather Monday night/Tuesday, but otherwise seasonably mild next week

Given general agreement amongst all the various models, the blended model guidance (NBM) looks pretty reasonable for the long term, so pretty much went with it. No huge changes from prior forecasts, although a bit more clarity on some of the details. Below are a few notes to add to the key messages above:

Saturday: Region will be solidly in the warm sector with 850mb temps in the 12-14C range. That easily supports surface temperatures well into the 70s to around 80f and if we have more sun than expected, lower 80s are possible. Currently guidance shows a 30-50% chance of 80F or higher from NE MA (incl Boston) southwest across northern RI/central MA and into northern CT. Basically the normally warmer parts of the area. The other notable sensible weather will be the winds. Forecast soundings suggest the boundary layer could become rather deep (up 850mb/5000ft) and tap into 30-35kt winds aloft. That would mean we should see rather gusty winds, especially in the afternoon. Current forecast has 25-35mph peak gusts, but this might be a bit on the low side in some areas. Guidance shows about a 40% chance of 40mph or higher gusts across the higher terrain in northern CT/central and western MA. There is also some low level instability and small CAPE, resulting in small chances for a thunderstorm. However it's quite conditional as there is a mid level warm cap (inversion) that should be enough to keep convection from developing. However if the cap is a little weaker, a rogue spot shower or isolated brief thundershower is possible, especially across higher terrain.

Sunday: A cooler and much drier airmass will overspread the region.
Plenty of sun will promote excellent boundary layer mixing, and by the afternoon we will probably mix up to 6000-7000ft. As with Saturday, winds aloft will be running around 35kt, so anticipate another gusty afternoon. The probabilies of seeing wind gusts above 40mph is a bit higher than on Saturday. However not looking like any real impact from the winds. The dry airmass will also drop afternoon humidities rather low (into the 20-25% range). Could be a day with potential fire weather concerns, all depending on how much precip we get Saturday night with the frontal passage (not expected to be much at this point).

Monday Night/Tuesday: looks like the primary period of time next week with the highest chance of seeing rain. Not anything really noteworthy however. Fairly progressive upper level flow will be in place, and as a shortwave moves across, this will produce weak low pressure and accompanying precipitation. Dynamics are not impressive, and no instability is expected -- thus perhaps 1/4" of rain is about it.

AVIATION /23Z THURSDAY THROUGH TUESDAY/
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

00Z TAF Update

High confidence through the period.

VFR currently, and that will continue area wide overnight and all day Friday. Expect another round of gusty southwest surface winds to develop after 15-17z on Friday. Expect most areas will experience fairly common gusts of 25-30kt. Some mid-level clouds start to move in late in the day.

Still looks like VFR for Friday night, although there may be a spot shower that falls from mid level cloud deck with ceilings probably in the 7000-11000ft range. Surface winds will continue to gust to 20kt in many areas. Also expecting fairly widespread LLWS to develop after 00z Saturday with winds around 2000ft reaching 45-55kt after midnight.

KBOS TAF...High confidence.

KBDL TAF...High confidence.

Outlook /Saturday through Tuesday/...

Saturday: VFR. Windy with local gusts up to 30 kt. Slight chance SHRA.

Saturday Night: Mainly VFR, with local MVFR possible. Breezy.
Slight chance SHRA.

Sunday: VFR. Breezy.

Sunday Night through Monday: VFR.

Monday Night: Mainly VFR, with local IFR possible. Chance SHRA.

Tuesday: Mainly VFR, with areas IFR possible. Breezy. Chance SHRA.

MARINE
Forecaster Confidence Levels:

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

Overall high confidence in the forecast.

Tonight

Clear skies with modest westerly winds around 5 knots over the coastal waters tonight. SCY seas over the outer waters south of the Islands subside below 5 feet before midnight and fall to 1 to 2 feet across all marine zones by tomorrow morning.

Tomorrow

Winds gradually increase out of the southwest late tomorrow morning into tomorrow evening. Southwest winds from 15 to 20 knots for most of the afternoon hours with gusts from 20 to 25 knots. Seas build to 2 to 4 feet by late tomorrow afternoon.

Tomorrow Night

15 to 20 knot southwest winds persist tomorrow night with some 25 to 30 knot gusts possible. Small Craft Advisories headlines will likely be needed and may be issued with tomorrow mornings forecast package.
Seas build to 7 feet over the outer south coastal waters and 3 to 5 feet elsewhere.

Outlook /Saturday through Tuesday/...

Saturday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 9 ft.

Saturday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Slight chance of rain showers.

Sunday: Winds less than 25 kt. Local rough seas.

Sunday Night: Winds less than 25 kt. Seas locally approaching 5 ft.

Monday: Winds less than 25 kt.

Monday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers.

Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Chance of rain showers.

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