Marine Weather Net

Boston Harbor Marine Forecast


TODAY

E
WINDS
25 - 30
KNOTS

TONIGHT

SW
WINDS
10 - 15
KNOTS

SUN

SW
WINDS
15 - 20
KNOTS

SUN NIGHT

W
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
ANZ230 Forecast Issued: 716 AM EST Sat Jan 16 2021

GALE WARNING IN EFFECT UNTIL 2 PM EST THIS AFTERNOON
Today...E Winds 25 To 30 Kt With Gusts Up To 45 Kt, Becoming S 15 To 20 Kt With Gusts Up To 35 Kt This Afternoon. Waves 5 To 8 Ft, Except 8 To 11 Ft At The Outer Harbor Entrance. Rain This Morning, Then Showers Likely This Afternoon. Vsby 1 Nm Or Less, Increasing To 1 To 3 Nm This Afternoon.
Tonight...Sw Winds 10 To 15 Kt, Increasing To 15 To 20 Kt After Midnight. Gusts Up To 30 Kt. Waves 4 To 7 Ft.
Sun...Sw Winds 15 To 20 Kt With Gusts Up To 30 Kt. Waves 3 To 5 Ft.
Sun Night...W Winds 10 To 15 Kt. Gusts Up To 30 Kt, Decreasing To 20 Kt After Midnight. Waves 2 To 3 Ft.
Mon And Mon Night...W Winds 10 To 15 Kt With Gusts Up To 20 Kt. Waves Around 2 Ft.
Tue Through Wed Night...W Winds 10 To 15 Kt With Gusts Up To 20 Kt. Waves Around 2 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
753am EST Sat Jan 16 2021

Synopsis
Intensifying low pressure will bring heavy rain this morning, with accumulating wet snow across the high terrain of Western Massachusetts. The low tracks into Northern New England this afternoon, giving way to a drying and colder trend into Sunday and early next week. Weak weather systems may bring scattered light snow showers Wednesday and Friday.

Near Term - Until 6pm This Evening
755 AM

Heavy wet snow falling across the high terrain in far northwest MA. While this wet snow will be changing to rain through the morning, significant accumulations will occur at elevations above 1500 feet. Heavy wet snow of 4 to 9 inches may result in some downed trees and scattered power outages. We have upgraded northwest Franklin County to a Winter Storm Warning. No other changes to the forecast.

Previous Discussion... ** Heavy rain with 1-2 inches likely *** *** Heavy wet snow in the high terrain of Northwest MA *** *** Strong Winds East Coastal Massachusetts ***

Heavy Rain... Impressive satellite imagery early this morning, displaying a well developed and robust warm/moist conveyor belt (WCB) streaming up the Eastern Seaboard, with noticeable cooling cloud tops. Embedded within this WCB are wind anomalies of +3 to +4 standard deviations (SD), acting on abundant Atlantic moisture with PWAT (Precipitable Water) around 1 inch (+3 SD)! In fact the daily PWAT (Precipitable Water) record at CHH today is 1.13 inches. Nevertheless, strong forcing for ascent within a moist/saturated airstream supports widespread rainfall of 1-1.5 inches. Strong low level southeast jet of 60-70 kt at 925 mb will move across the region this morning and yield upslope component across the hilly terrain of MA/RI/CT. This is where isolated rainfall amounts of 2- 2.5 inches is possible. Not expecting river/stream flooding given recent dry stretch of weather, yielding plenty of river/stream capacity and lack of frozen ground not enhancing runoff. Therefore any flooding will be limited to minor poor drainage/street-highway flooding. Nonetheless, these rainfall rates will increase the risk of hydroplaning this morning.

Strong Winds... 00z models trended stronger with low level jet and extended jet core closer to the surface, with 50-60 kt down to about 500 ft across Eastern Coastal MA, as jet intensifies before exiting offshore around 18z. Model soundings suggest most of this wind remains aloft, however heavy downpours and 50 kt of wind only about 500 ft off the deck, supports 20-30 mph with gusts up to 50 mph at the surface this morning into early afternoon for the East coast of MA. Therefore hoisted a wind advisory for this region. Elsewhere, winds not as strong thus no headlines, but sufficient for a wind swept rain. Winds drop off between 10 am to 1 pm from west to east.

Short Term - 6pm This Evening Through 6pm Sunday
4 AM

Tonight... Mainly dry but can't rule out some Lake Effect cloudiness and isolated flurries in the upslope region of Western-Central MA/CT. Cooler but still above normal with lows in the upper 20s and lower 30s. But blustery WSW winds will make it feel even cooler.

Sunday... Dry but chilly cyclonic flow with 850 mb temps cooling off to about - 6C. Although with downsloping winds highs should warm to 40-45, upper 30s high terrain.

Long Term - Sunday Night Through Friday
Marine
*** Gale Warning continues through midday ***

4 AM

Today...ESE gales as low pressure tracks across New England. Heavy rain this morning limiting vsby. Wind shift from ESE to SSW 15z-18z from west to east. Drying trend and improving vsby with the wind shift.

Tonight...Westerly gales possible as strong low moves across ME. Dry weather and good vsby.

Sunday...980 mb in the Maritimes yields marginal westerly gales. Dry weather and good vsby.

Outlook /Sunday Night through Wednesday/... Sunday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 13 ft.

Martin Luther King Jr Day: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas.
Monday Night: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas.

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

Tuesday Night: Winds less than 25 kt. Local rough seas. Slight chance of rain showers, slight chance of snow showers.

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

Tides / Coastal Flooding
400 AM

No change from previous thinking, storm surge of 1.5 to 2.0 ft along the Eastern MA coastline as high tide approaches around 130 pm this afternoon. Will continue with Coastal Flood Advisory for minor flooding across the entire Eastern MA coastline, but greatest threat is from Boston northward thru Cape Ann to the MA/NH border, as low level jet increases as it departs our region. This will result in greatest surge and wind in this region.

NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...Wind Advisory until noon EST today for MAZ020. Wind Advisory until 2pm EST this afternoon for MAZ007-015-016- 019-021>024. Coastal Flood Advisory until 3pm EST this afternoon for MAZ007-015-019. Winter Weather Advisory until 9am EST this morning for MAZ008. Winter Storm Warning until noon EST today for MAZ002. RI...Wind Advisory until noon EST today for RIZ006>008.
MARINE...
Gale Warning until 11am EST this morning for ANZ231>234. Gale Warning until 2pm EST this afternoon for ANZ230-236-250- 251-254-255. Gale Warning until 10am EST this morning for ANZ235-237-256.