Marine Weather Net

Cape Cod Bay Marine Forecast


REST OF TONIGHT

NE
WINDS
10 - 15
KNOTS

THU

NE
WINDS
10 - 15
KNOTS

THU NIGHT

E
WINDS
5 - 10
KNOTS

FRI

S
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
ANZ231 Forecast Issued: 116 AM EDT Thu Sep 20 2018

SMALL CRAFT ADVISORY IN EFFECT UNTIL 5 AM EDT EARLY THIS MORNING
Rest Of Tonight...Ne Winds 10 To 15 Kt With Gusts Up To 25 Kt. Seas 3 To 5 Ft.
Thu...Ne Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 2 To 4 Ft. A Chance Of Showers.
Thu Night...E Winds 5 To 10 Kt. Seas 2 To 3 Ft.
Fri...S Winds 5 To 10 Kt, Increasing To 10 To 15 Kt With Gusts Up To 25 Kt In The Afternoon. Seas 2 To 4 Ft.
Fri Night...Sw Winds 10 To 15 Kt, Increasing To 15 To 20 Kt After Midnight. Gusts Up To 30 Kt. Seas 2 To 4 Ft. A Chance Of Showers.
Sat...W Winds 10 To 15 Kt With Gusts Up To 30 Kt, Becoming N With Gusts Up To 20 Kt In The Afternoon. Seas 2 To 4 Ft. A Chance Of Showers.
Sat Night...Ne Winds 5 To 10 Kt. Seas 2 To 3 Ft.
Sun...Ne Winds 5 To 10 Kt. Seas 1 Foot Or Less.
Sun Night...Ne Winds 5 To 10 Kt. Seas Around 2 Ft.
Mon...Ne Winds 10 To 15 Kt. Seas 2 To 4 Ft.
Mon Night...E Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 2 To 4 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
948pm EDT Wednesday September 19 2018

Synopsis: High pressure builds into New England tonight and Thursday yielding dry cool weather. Warmer Friday ahead of an approaching cold front then turning cooler over the weekend as high pressure builds into the area from the Great Lakes.

Near Term - Until 6am Thursday Morning
945pm update... Widespread lower clouds have developed across SNE. There are some breaks across SE MA but expect clouds to fill in. Plenty of low level moisture within moist NE flow so clouds will persist much of the night, but partial clearing should develop in the interior late tonight and toward daybreak as moisture thins away from the coast. Gusty NE winds will continue across Cape/Islands. No change to forecast low temps.

Short Term - 6am Thursday Morning Through Thursday Night
Heigheights will again be on the rise through the day Thursday as the upper ridge builds over the east coast and our surface high center builds further south. The light winds and subsidence associated with the high pressure will keep a lid on our low level moisture and at least partly cloudy skies with some sun mixed in are likely to persist though the day, with the clearest skies to the west. There is some uncertainty as to how long the clouds will hang on. We could even see some drizzle early, especially nearer to the coast. Highs are expected to be similar to today in eastern MA/RI, but a few degrees cooler in the CT valley, around 70.

Thursday night a surface low moving up through the Great Lakes region will drag a warm front up through our region. Most of the synoptic guidance keeps the majority of the rainfall to our north but we'll see rain chances increase for northwestern MA late Friday night/early Friday morning. warm air advection associated with this front will potentially work to offset any radiational cooling we can get if skies clear out enough, but right now temps look to bottom out in the low to mid 50s

Long Term - Friday Through Wednesday
Highlights... * A warm front will bring a few showers across north central and western areas early Fri * A cold front approaches late Fri, bringing scattered showers and isolated thunderstorms especially across the interior * Large high pressure builds in from central and eastern Canada Saturday afternoon into Monday, bringing cool, dry conditions

Overview... 19/12Z guidance suite remains in rather good agreement with their synoptic patterns through much of this weekend. The differences in timing and amplitude of a potent mid level shortwave start to creep into the forecast early next week. Main forecast theme for the overall pattern continues. Nearly zonal flow transitions to weak ridging Friday, then back to a more zonal flow this weekend. We may see another brief warmup early next week as an upstream trough amplifies a ridge over the Northeast USA. Should this occur as currently expected, we could be looking at widespread low temperatures in the 40s Sunday night.

A low pressure moving across eastern Canada should push its warm front through our region Friday, with its cold front crossing our region Friday night into Saturday morning. This has been a consistent timing for these features. High pressure over northern New England dominates this weekend. A pair of weak fronts could be near our region early next week, but its a low confidence forecast.

Marine Discussion
Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.
Short Term /through Thursday Night/... Decided to post a Small Craft Advisory into Cape Cod Bay tonight for 5 ft seas across the northern half of the Bay. Also extended a Small Craft Advisory for the south coastal MA bays and sounds.

Previous Discussion... Through Tonight...High confidence. Northeast winds will increase through the day, gusting to 30 mph in the south and eastern waters, higher to the southeast closer to the low pressure center. Seas building to 5-6 ft. Waters will be more tranquil further to the north. Wind gusts slowly diminish Thursday morning.

Thursday...High confidence. NE winds decreasing through the day as high pressure builds south. Seas will remain up to 5 ft over the eastern waters through the day.

Outlook /Friday through Monday/... Friday: Low risk for Small Craft Advisory winds with areas of gusts up to 30 kt. Seas up to 5 ft.
Friday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Slight chance of rain showers, isolated thunderstorms.

Saturday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Slight chance of rain showers.
Saturday Night: Winds less than 25 kt. Seas locally approaching 5 ft.
Sunday: Winds less than 25 kt.

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

NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None.
MARINE...
Small Craft Advisory until 5am EDT Thursday for ANZ231>235.
Small Craft Advisory until 8pm EDT Thursday for ANZ250-254.
Small Craft Advisory until 8am EDT Thursday for ANZ251-255- 256

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