Marine Weather Net

East of Ipswich Bay and the Stellwagen Bank Marine Sanctuary Marine Forecast


TODAY

W
WINDS
5 - 10
KNOTS

TONIGHT

W
WINDS
5 - 10
KNOTS

SAT

NW
WINDS
10 - 15
KNOTS

SAT NIGHT

NW
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
ANZ250 Forecast Issued: 716 AM EST Fri Nov 27 2020

Today...W Winds 5 To 10 Kt. Seas 2 To 4 Ft. Areas Of Fog This Morning With Vsby 1 Nm Or Less.
Tonight...W Winds 5 To 10 Kt, Becoming Nw 10 To 15 Kt After Midnight. Seas 2 To 3 Ft.
Sat...Nw Winds 10 To 15 Kt. Gusts Up To 20 Kt In The Afternoon. Seas 2 To 4 Ft.
Sat Night...Nw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 3 To 4 Ft.
Sun And Sun Night...S Winds 10 To 15 Kt. Seas 2 To 4 Ft.
Mon...Se Winds 25 To 30 Kt With Gusts Up To 35 Kt. Seas 4 To 7 Ft. Showers.
Mon Night And Tue...Se Winds 25 To 30 Kt, Becoming S 20 To 25 Kt. Gusts Up To 40 Kt. Seas 9 To 12 Ft, Building To 9 To 14 Ft. Showers.
Tue Night...Sw Winds 10 To 15 Kt With Gusts Up To 25 Kt. Seas 8 To 11 Ft. A Chance Of Showers. 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
654am EST Fri Nov 27 2020

Synopsis
High pressure will bring mainly dry and quiet weather through Sunday. Confidence increasing in impactful weather as a strong low lifts into the region. This will bring the potential for strong winds and heavy rain. Above normal temperatures early in the week becoming more seasonable by midweek.

Near Term - Until 6pm This Evening
640 AM

Made minor adjustments to the add areas of fog where they are currently being observed. Remainder of the forecast looks good, so did not make any additional changes.

Discussion from 425 AM

* Areas of fog will be locally dense early this morning especially across eastern MA

Lingering low level moisture coupled with light wind has resulted in areas of fog early this morning, some of which was locally dense. The fog was rather shallow and there has been an improvement over the last few hours across parts of interior MA/CT and RI. This a result of a bit drier air working in from the west. The fog will be slowest to lift across eastern MA, but still expect significant improvement in this region by mid morning. Low-lying locations will be the slowest to improve.

After the fog dissipates, we probably will be dealing with an abundance of strato-cumulus through the afternoon given ample low level moisture. However, peeks of sunshine and a relatively mild airmass in place should allow high temps to recover into the middle to upper 50s in many locales. If we see a bit more sunshine than what is currently expected, we may reach 60 across parts of RI/SE MA.

Dry weather should generally prevail today, but a spot sprinkle/light shower or two is possible across CT/RI and SE MA late in the day with the approach of a weak frontal boundary.

Short Term - 6pm This Evening Through 6pm Saturday
Tonight... A spot shower or two remains possible this evening across RI/SE MA in association with a weak front. Generally though dry weather will be the rule with light winds. Low temps should bottom out in the 30s to the lower 40s. We may see some patchy fog develop in the typically prone locations, but it should not be as dense or widespread as early this morning.

Saturday... It will be a few degrees cooler on Sat behind the weak cold front, but nothing out of the ordinary for this time of year. A scattered to broken deck of strato-cumulus clouds are anticipated, but we should still see periods of partial sunshine. Perhaps a brief spot shower across the interior with a moisture starved shortwave, but it generally will remain be dry. Highs should range from the upper 40s in the higher terrain to mainly the lower 50s elsewhere. Winds will be from the northwest at 5 to 15 mph, so a decent day for late November standards.

Long Term - Saturday Night Through Thursday
Highlights

* Dry and quiet weather Saturday night through Sunday. Temperatures will be a bit cooler, but seasonable for this time of year.

* Strong storm system impacting southern New England later on Monday into Tuesday. This will bring heavy rain, strong winds, and the potential for coastal flooding.

* Trending cooler mid to late in the week, but seasonable. Isolated to scattered shower chances.

Saturday night through Sunday... Ridge axis builds from the Ohio River Valley Saturday night into the eastern Great Lakes/southern New England by late Sunday. High pressure will nudge into the region from the Mid Atlantic Saturday night and build just to the south/southeast of southern New England on Sunday.

Expect the weather to be dry and quiet Saturday night through Sunday as high pressure builds in. Should have strong radiational cooling across southern New England Saturday night due to the combination of clear skies and light winds. Have put the 10th percentile of guidance, which brings down lows to the mid 20s across northwest MA and the 30s across the rest of southern New England.

As the high shifts to the SE of southern New England on Sunday will see flow aloft shift from the WNW to the SW at 925 hPa, which will advect warmer air into southern New England. Will be slightly cooler in comparison to Saturday, but still seasonable for this time of year. Highs range from the 40s across the higher elevations to the low 50s across the Merrimack and CT River Valley.

Monday and Tuesday... Not much has changed in the latest update. Complex and highly amplified pattern for early in the week. Main focus is on a northern stream trough phasing with a southern stream cutoff. A positively tilted trough over the Upper Mississippi River Valley digs into the central Great Lakes/Ohio River Valley by late Sunday and early Monday. This pulls in the cutoff low as it lifts from the Lower Mississippi River Valley into the Ohio River Valley. Expect a cutoff to develop over the Ohio River Valley/central Great Lakes due to the interaction of the two streams on Monday. This cutoff will slowly rotate into the eastern Great Lakes on Tuesday. A surface low will rapidly deepen over Tennessee Valley late on Sunday and lift northeastward into the eastern Great Lakes and mid Atlantic. The occluded/cold front associated with the system will slide into southern New England late in the day. The surface low will remain over the eastern Great Lakes/southern Quebec on Tuesday as the occluded/cold front slides offshore.

Good agreement amongst guidance depicting a strong wind and heavy rain event. Still continue to see strong southwesterly flow, which will advect 1" to 1.5" PWATs (Precipitable Waters) which is around 2-3 STD above normal with the moisture plume originating from the Gulf of Mexico. Models continue to show a potent low level jet. The international guidance is a bit more bullish than the GFS. Generally seeing anywhere from a 50-70+ low level jet. Have nudged the forecast toward the latest ECMWF, which bumps up the wind speeds and gusts a bit from the previous forecast. The core of the low level jet is currently forecast to impact eastern portions of the CWA with the highest gusts expected across Cape Cod and the Islands. Model soundings show 60-70 kt winds roughly 1 to 2 kft AGL. Would not be surprised if wind headlines will be needed in future updates, but still need to hammer down the details of the low level jet. The international guidance still features more of a straight southerly low level jet - and stronger than the GFS which is a bit more of a southeasterly oriented jet and a bit weaker. This has implications as the straight southerly and stronger flow would bring a higher risk of coastal flooding for the south coast versus more southeasterly oriented winds. Luckily, astronomical high tides are on the low side for this period, which should lessen the risk.

Wednesday And Thursday
Confidence in the forecast is fairly low. Models are all over the place with mass fields and the synoptic setup. Have leaned heavily on the NBM guidance due to the large differences during this window. Temperatures cool down toward seasonable readings for early December which is highs generally in the 40s.

Marine


Today...High confidence. Main issue will be areas of fog this morning that will be locally dense, but we do expect improvement by afternoon. Otherwise, weak gradient will keep winds below SCA thresholds but have continued SCA (Small Craft Advisory) headlines for lingering swell across our southern waters.

Tonight and Saturday...High confidence. Weak pressure gradient will keep winds/seas below SCA (Small Craft Advisory) thresholds.

Outlook /Saturday Night through Tuesday/... Saturday Night: Winds less than 25 kt. Seas up to 5 ft.

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

Monday: Low risk for gale force winds with gusts up to 40 kt. Areas of rough seas. Rain showers.

Monday Night: Moderate risk for gale force winds with local gusts up to 45 kt. Rough seas up to 15 ft. Rain showers.

Tuesday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 15 ft. Chance of rain showers.
NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None.
MARINE...
Small Craft Advisory until 7am EST this morning for ANZ232>235-237. Small Craft Advisory until 4pm EST this afternoon for ANZ254>256.