Narragansett Bay Marine Forecast
|Tonight...Nw Winds 10 To 15 Kt With Gusts Up To 25 Kt. Waves 1 Foot Or Less.|
|Tue...Nw Winds 10 To 15 Kt With Gusts Up To 25 Kt. Waves Around 2 Ft.|
|Tue Night...W Winds 10 To 15 Kt With Gusts Up To 25 Kt. Waves 2 To 3 Ft.|
|Wed...W Winds 10 To 15 Kt With Gusts Up To 20 Kt. Waves 2 To 3 Ft.|
|Wed Night...W Winds 5 To 10 Kt. Waves 1 Foot Or Less.|
|Thu And Thu Night...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Waves 2 To 3 Ft.|
|Fri And Fri Night...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt, Becoming W 5 To 10 Kt. Waves 2 To 3 Ft.|
|Sat...N Winds 5 To 10 Kt. Waves Around 2 Ft. A Chance Of Rain.|
|Sat Night...Nw Winds 5 To 10 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.|
| Area Forecast Discussion|
National Weather Service Boston/Norton MA
715pm EDT Monday Oct 18 2021
Seasonable but blustery conditions continue Tuesday. Unseasonably warm temperatures are on the way for mid-week as a ridge builds in from the west. Mild temperatures persist through Thursday before cold front sets sigheights on New England, bringing in a chance for showers Friday and much cooler temperatures for the weekend.
Near Term - Until 6am Tuesday Morning
Previous forecast remains on track and no changes to the forecast are needed at this time. See previous discussion for further details.
The combination of the short wave feature across upstate NY rotating through our area and the loss of daytime heating, cold pool(a region of relatively cold air) showers begin to dissipate around sundown. Additionally, a stabilizing boundary layer overnight will cause wind gusts to fall off, with gusts falling to about 10-15 kt from the daytime high of 25-30 kt. Highest winds will remain along the coast.
As a noticeably drier 850mb-500mb airmass begins to rotate in from the west overnight, clouds will also begin to dissipate across the entire region. By sunrise, much of our region will be under mostly clear skies, but cloud cover may linger across the Cape and Islands as the area of moisture is last to pass through this region.
Dewpoints overnight will be mainly in the low to mid 30s, but winds around 10 kt will prohibit temperatures from cooling by optimal radiational cooling conditions. This, combined with cloud cover during the first half of the overnight hours means that temperatures will likely stay 6-8F above forecasted dews, in the upper 30s and low 40s area wide; portions of the Cape look to remain around 50 degrees overnight.
Patchy frost is possible across far northwestern MA overnight, as forecast lows settle around 35 degrees. Should cloud cover clear more quickly than forecast, or winds die back more than expected, frost may be a bit more widespread. Most portions of our CWA should avoid a frost overnight. Climatologically, we are well past the average first frost for our area.
Short Term - 6am Tuesday Morning Through Tuesday Night
Tuesday looks to be a bit of an improvement compared to Monday. As mid level dry air continues to rotate in from the west, cloud cover will be much less widespread. Additionally, warmer air aloft, to the tune of +3-4C at 825 mb compared to Mondays subzero temps, will allow many portions of the area to warm into the low 60s. Of note, the Connecticut River Valley will achieve temperatures about 6-8 degrees above Monday's highs.
The primary weather concern for Tuesday will again be gusty winds, with some guidance pointing towards 40 kt gusts at 825 mb. We do not look to mix as high tomorrow as we did on Monday, to perhaps 875 mb, meaning that the highest gusts would not mix to the surface. However, even an 925 mb, there are 30 kt gusts forecast.
The low pressure system that brought showers to our area on Monday begins to move off to our north and east on Tuesday as a mid level ridge begins to build in from the west. Some residual mid level moisture stalls just to our northeast, so some mid level clouds will likely form, especially across eastern MA.
Overnight, winds once again decouple and gusts become less fierce; W/NW at 5-10 kt. A second surge of moisture will bring dewpoints back into the 40s and low 50s, which combined with light winds will keep temperatures from radiating, lows expected in the low to mid 50s. By daybreak Wednesday, winds flow solidly from the west.
Long Term - Wednesday Through Monday
Highlights... * Warmer temperatures mid-week
* Unsettled weather late week and this weekend with more seasonable temperatures
Wednesday and Thursday
Mid-level ridge axis over the Midwest will gradually build eastward over the east coast between Wednesday and Thursday. This will set southern New England up for unseasonably warm temperatures on both Wednesday and Thursday afternoons. On Wednesday modest warm air advection in the mid-levels will increase temperatures at 850 hPa to just shy of 10 Celsius. With a modest pressure gradient still in place we should see fairly deep mixing to the 850 hPa level. Thus we should see high temperatures at the surface reach the upper 60s to low 70s for many areas of southern New England.
By Thursday the mid-level ridge axis is forecast to be east of southern New England resulting in a transition from westerly to southwesterly flow. This will support stronger warm air advection in the low levels with temperatures at 850 hPa climbing to 11-12 Celsius. Therefore we should see slightly warmer temperatures on Thursday afternoon in the low 70s.
Friday through Monday
After another warm Friday afternoon, seasonable temperatures and unsettled weather are forecast for the weekend. There is a fair bit of spread with respect to the development of a coastal low-pressure system and rain chances on Saturday. This will be the forecast problem of the week. Have leaned on NBM in the mean time which reasonably points toward chance/slight chance Probability of Precipitation for Saturday afternoon. Toward the end of the weekend and early next week, there is a fair bit of agreement in the models for a more robust cold frontal passage that would bring a chance for showers Monday followed by cooler/drier conditions early next week.
Forecaster Confidence Levels.
Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.
Persistent strong NW flow continues into Wednesday morning, with SCA's (Small Craft Advisories) extended for the southern outer waters through 12 Wednesday. Our eastern and interior waters will fall below SCA criteria late Tuesday. Given that gusts are unlikely to exceed 30 kt on Tuesday, a Gale Watch was not considered.
Outlook /Wednesday through Saturday/... Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft.
Wednesday Night: Winds less than 25 kt.
Thursday: Winds less than 25 kt. Seas locally approaching 5 ft.
Thursday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas.
Friday: Winds less than 25 kt. Local rough seas.
Friday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain.
Saturday: Winds less than 25 kt. Slight chance of rain.
NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None.
Small Craft Advisory until 8am EDT Wednesday for ANZ232>235- 237. Small Craft Advisory from 2am to 8pm EDT Tuesday for ANZ230- 236. Small Craft Advisory until 8pm EDT Tuesday for ANZ231-251. Small Craft Advisory until 8pm EDT Tuesday for ANZ250. Small Craft Advisory until 8am EDT Wednesday for ANZ254>256.