Marine Weather Net

Boston Harbor Marine Forecast


20 - 25


10 - 15




5 - 10

The Marine Weather Forecast In Detail:
ANZ230 Forecast Issued: 934 AM EST Fri Nov 16 2018

This Afternoon...Ne Winds 20 To 25 Kt, Becoming Nw. Gusts Up To 35 Kt. Waves Around 2 Ft, Except 10 To 11 Ft At The Outer Harbor Entrance. Rain Early, Then A Chance Of Rain.
Tonight...W Winds 10 To 15 Kt With Gusts Up To 25 Kt. Waves Around 2 Ft. At The Outer Harbor Entrance, Waves Around 8 Ft, Subsiding To 4 Ft After Midnight.
Sat...W Winds Around 10 Kt With Gusts Up To 20 Kt. Waves Around 2 Ft.
Sat Night...W Winds 5 To 10 Kt. Waves Around 2 Ft.
Sun...Nw Winds 5 To 10 Kt. Waves 1 Foot Or Less.
Sun Night...E Winds Around 5 Kt, Becoming S After Midnight. Waves 1 Foot Or Less. A Chance Of Showers. Vsby 1 To 3 Nm After Midnight.
Mon...W Winds 5 To 10 Kt. Waves 1 Foot Or Less. A Chance Of Showers In The Morning.
Mon Night...Nw Winds Around 10 Kt. Waves Around 2 Ft.
Tue...Nw Winds Around 10 Kt. Waves 1 Foot Or Less.
Tue Night...Nw Winds Around 10 Kt. Gusts Up To 20 Kt After Midnight. Waves 1 Foot Or Less, Then Around 2 Ft After Midnight. 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
958am EST Fri Nov 16 2018

Synopsis: Rain will come to an end through early afternoon...but will change to a brief burst of snow in some locales across the interior before ending. Dry and chilly weather move in this afternoon and remain through the weekend as high pressure builds in. Weak low pressure may bring patchy light rain and/or snow late Sunday into Monday. Another shot of colder air moves in by the middle of next week, though it should be mainly dry.

Near Term - Until 6pm This Evening
955 am update... Associated low pressure system and its closed mid level circulation were tracking across southeast New England this morning. Wrap around precipitation in the form of rain was impacting much of the region...but colder temperatures aloft were working back into portions of the interior. The result was rain was changing back to snow in some locations. Although the heavier bands were somewhat disorganized...some locales mainly across interior MA and CT may see a brief burst of moderate to heavy snow. An additional one half to two inches of snow may impact portions of the region through lunchtime. This may result in some roads becoming briefly slippery and we did issue a special weather statement. Across eastern MA and RI...ptype will mainly be rain but some wet flakes may mix in at the end.

All the precipitation should pretty much be over by early afternoon as the low departs. Clouds will hang tough through most of the afternoon with gusty northwest winds. Temperatures generally be in the 30s.

We canceled most of the wind headlines...except for the Cape/Nantucket where they may flirt with criteria through lunch time. Also...left the Winter Weather Advisory for the Berks but maybe able to cancel it a few hours early based on trends

Short Term - 6pm This Evening Through Saturday Night
A broad upper trough lingers over Hudson Bay through Saturday night. Several shortwaves move through this flow and over Southern New England. 500-mb heigheights remain near to below normal through the period. Normal values are 557 to 563 Decameters, while forecast values are in the 540s Today and 550-555 Saturday.

One shortwave moves across Southern New England early tonight. This may be enough to generate scattered snow showers, especially across northern Massachusetts. These snow showers should move out of state before midnight.

Cold advection will maintain some level of mixing tonight and Saturday. Low level winds will be 30-35 kts tonight and 20-25 kts Saturday. Expect most or all of this wind to mix to the surface in gusts tonight and Saturday.

Moisture cross sections show diminishing moisture aloft on Saturday. This suggests a dry day, allowing for sunshine.

Temperatures upstream are in the upper 20s and lower 30s...this should suffice for tonight's min temps. Mixing on Saturday should reach 925 mb, where temps will support max surface temps in the 40s. Min temps farther upstream point to Saturday night mins in the mid 20s to lower 30s

Long Term - Sunday Through Thursday
Highlights... * No changes to Thursday afternoon long term forecast for this period. * Below average temperatures persist * Weak low pressure brings periods of rain and snow late Sunday into Monday * Dry and cold mid week

Overview... The extended forecast features a few high pressure systems sandwiched around a relatively weak low pressure disturbance or two in the Sunday night/Monday time frame which will bring the return of both rain and snow chances. Model consensus is good that the flow pattern becomes much less amplified and more zonal behind Friday's system, persisting through late weekend. By then a mid level shortwave digs south, crossing the region Sunday/Monday which will generate a weak surface low in the vicinity of SNE with another round of light snow/rain. Beyond this, models diverge a bit, with the GFS keeping things unsettled into Tuesday before the high returns, while the Euro returns a dry high pressure more quickly. Either way, by mid to late week heigheights begin to rise ever so slightly and a cold and dry pattern returns.

Details... Sunday and Monday... Sunday high pressure sits over the northeast with light winds and highs in the upper 30s-40s under a cold airmass; should be a mostly dry day before snow/rain chances increase from the west by the evening/overnight hours. The upper trough over Canada digs south helping to generate a surface low in the vicinity of SNE which brings weak fronts through in quick succession Sunday night/Monday. Still expecting mainly snow outside the coastal plain, with rain along the coasts. Quantitative Precipitation Forecast amounts are lackluster; a few hundredths to a few tenths of liquid equivalent.

Tuesday through Thursday... After the system exits zonal flow returns at the base of a large 500 mb trough over the eastern US Tuesday/early Wednesday. Some disagreement on slight precipitation chances Tuesday, but overall looks dry; maybe some showers over the high terrain. By mid week a surface high returns bringing dry weather. Given the overall weak longwave trough pattern, cold temperatures will persist with highs in the 30s and low 40s.

Marine Discussion
Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.
Short Term /through Saturday Night/...High confidence.

Today...We downgraded the remaining Storm headlines to gales with strong small craft across Boston Harbor/Narr Bay. Seas remain quite high though as strong easterly flow as Buoy 44013 was still at 18 feet. Seas will gradually lower as winds shift to the west...but they will remain quite high.

Tonight... West winds at 20 kt gusting to 30 kt. Seas 8 to 12 feet slowly subsiding during the night.

Saturday... West winds gusting 20 to 25 kt. Seas slowly diminishing, but the outer waters will remain with 5 foot seas.

Saturday night... Winds less than 25 kt. Seas diminishing below 5 feet on the outer waters.

Outlook /Sunday through Tuesday/... Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.
Sunday Night: Winds less than 25 kt. Slight chance of rain. Local visibility 1 to 3 nm.

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

NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...Wind Advisory until noon EST today for MAZ022-024. Winter Weather Advisory until 3pm EST this afternoon for MAZ002-008-009. RI...None.
Gale Warning until 3pm EST this afternoon for ANZ231>235-237- 250-251-254>256.
Small Craft Advisory until 3pm EST this afternoon for ANZ230- 236

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