Boston Harbor Marine Forecast
|Today...N Winds Around 5 Kt, Becoming Se This Afternoon. Waves 1 Foot Or Less.|
|Tonight...S Winds Around 5 Kt, Becoming N 10 To 15 Kt With Gusts Up To 25 Kt After Midnight. Waves Around 2 Ft.|
|Mon...Ne Winds 15 To 20 Kt, Becoming E 10 To 15 Kt In The Afternoon. Gusts Up To 25 Kt. Waves 2 To 3 Ft.|
|Mon Night...E Winds Around 10 Kt. Waves 2 To 3 Ft.|
|Tue...Se Winds 10 To 15 Kt. Gusts Up To 20 Kt In The Afternoon. Waves 2 To 3 Ft. Rain Likely.|
|Tue Night...S Winds Around 10 Kt. Gusts Up To 20 Kt In The Evening. Waves 2 To 3 Ft. Patchy Fog. Showers. Vsby 1 To 3 Nm.|
|Wed...S Winds Around 10 Kt. Waves Around 2 Ft. Patchy Fog. A Chance Of Showers. Vsby 1 To 3 Nm.|
|Wed Night...Sw Winds 5 To 10 Kt. Waves 1 Foot Or Less. Patchy Fog. A Chance Of Showers. Vsby 1 To 3 Nm.|
|Thu...N Winds 5 To 10 Kt. Waves 1 Foot Or Less.|
|Thu Night...Ne Winds Around 5 Kt. Waves 1 Foot Or Less. 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.|
|Area Forecast Discussion|
National Weather Service Boston/Norton MA
815am EDT Sunday September 23 2018
Synopsis: High pressure will bring dry and seasonable temperatures today. A cold front moves south across the region late tonight followed by a surge of gusty northeast winds and unseasonably cool temperatures Monday. A warm front approaches with scattered showers across western areas Monday night. The showers will fall heavily at times during Tuesday. Warmer and more humid conditions return Tuesday night into Wednesday night, along with scattered showers and a few thunderstorms as a cold front approaches. Dry, seasonable conditions return late this week, though a few showers are possible Thursday night into Friday as a fast moving frontal system passes.
Near Term - Until 6pm This Evening
8am Update... Current forecast looks on track. Some patchy fog in the river valleys of far interior MA will lift and dissipate over the next couple of hours. Otherwise, continue to expect high cloud shield to gradually push south today.
Early Morning Discussion follows... High pressure remains in control today keeping deeper moisture and shower risk south of New Eng. High cloud shield expected to gradually push south across the region today with the most sunshine across northern MA but south coastal areas will see partial sunshine. Highs should top out near 70 degrees for most areas, a bit cooler along the coast where sea breezes will develop
Short Term - 6pm This Evening Through 6pm Monday
Mostly clear skies and light winds for much of tonight will result in another chilly night with lows dropping into the 40s for most locations. Main feature is backdoor cold front which drops south across the region late tonight, mostly after midnight, as strong high pressure builds across Quebec through Mon. A decent surge of gusty NE winds expected behind the front late tonight into Monday morning, especially across eastern MA where a period of gusts to 20-30 mph likely. Cross sections and soundings show a shallow layer of moisture around 900-950 mb developing by daybreak Monday across eastern MA then spreading west within moist low level E/NE flow. This will likely bring a fair amount of lower clouds to the region on Monday, but expect some breaks of sun as well. It will be much cooler Monday as 925 mb temps fall to 6-8C with a pocket of 4C air across NE MA. Highs will range from the mid/upper 50s across central and NE MA to lower 60s lower CT valley and RI/SE MA. A definite fall feel on Monday
Long Term - Monday Night Through Saturday
Highlights... * Rain and showers return Monday night/Tuesday, with locally heavy rainfall * Warm and humid Tuesday night into Wednesday night with scattered showers and a few thunderstorms possible * Seasonable temperatures late this week, with a few showers possible Thursday night into Friday
Details... Monday night... High pressure across northern New England will shift E into the Maritimes during Monday night. Should see dry conditions through around midnight, then area of rain will push into central and western areas during the early morning hours on Tuesday. Expect some gusty E-NE winds mainly along the coast. It will remain chilly especially across the higher inland terrain as temps bottom out in the lower-mid 40s.
Tuesday through Wednesday night... Warm front approaches Tuesday bringing periods of rain. PWATs increase to around 2 SD above normal, so there will be a swath of rain falling heavily at times on Tuesday. Could see between 0.75 and 1 inch of rainfall across central and western areas. There may be some pockets of poor drainage and urban flooding in the typically prone areas. At this point, still not expecting any flash flooding as rainfall rates not high enough. Temps will hold in the 60s across the region on Tuesday, possibly touching 70 along the S coast.
As the warm front moves through Tuesday night, temps will remain steady or slowly rise as showers continue. Instability increases with the milder, more humid air. K indices in the lower 30s and surface based LIs drop to -1 to -2. So have also mentioned isolated thunder ahead of an approaching cold front later Wed, pushing through Wednesday night. Temps will rise to the 70s ahead of the front during Wed, which will help enhance any convection.
Thursday through Saturday... Medium range model guidance continues to signal a fast moving northern stream mid level steering flow. At this point, any leftover showers early Thursday should move offshore as high pressure moves across. There may be a few showers as a weak H5 short wave moves across mainly after midnight Thursday night into Friday, then more dry, seasonal conditions as another high approaches Saturday.
Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.
Short Term /through Monday/...High confidence.
Today... Light winds and seas with high pressure over the waters.
Tonight and Monday... Increasing NE winds develop later tonight into Monday behind a backdoor cold front. Gusts to 25-30 kt likely across eastern MA waters late tonight into Monday morning with gusty winds shifting to south coastal waters during the day Mon. Small Craft Advisory will be issued for eastern MA waters starting late tonight and will likely need to be expanded to some of the south coastal waters on Monday.
Outlook /Monday Night through Thursday/... Monday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas.
Tuesday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Chance of rain, rain showers likely.
Tuesday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 8 ft. Rain showers likely, isolated thunderstorms. Local visibility 1 to 3 nm.
Wednesday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Chance of rain showers, isolated thunderstorms.
Wednesday Night: Winds less than 25 kt. Areas of rough seas. Chance of rain showers, isolated thunderstorms, patchy fog. Areas of visibility 1 to 3 nm.
Thursday: Winds less than 25 kt. Local rough seas. Slight chance of rain showers
NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None.
Small Craft Advisory from 8am to 8pm EDT Monday for ANZ232>235-237-255-256.
Small Craft Advisory from 4am to 2pm EDT Monday for ANZ230.
Small Craft Advisory from 6am to 4pm EDT Monday for ANZ231.
Small Craft Advisory from 4am to 8pm EDT Monday for ANZ250- 251.
Small Craft Advisory from 6am to 8pm EDT Monday for ANZ254