Narragansett Bay Marine Forecast
|This Afternoon...Sw Winds 10 To 15 Kt With Gusts Up To 25 Kt. Waves 3 To 5 Ft. A Slight Chance Of Showers.|
|Tonight...W Winds 10 To 15 Kt With Gusts Up To 30 Kt. Waves 2 To 4 Ft.|
|Thu...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Waves 2 To 3 Ft.|
|Thu Night...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Waves 2 To 3 Ft.|
|Fri...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Waves 2 To 3 Ft.|
|Fri Night...W Winds 5 To 10 Kt With Gusts Up To 20 Kt. Waves 2 To 3 Ft. A Chance Of Rain.|
|Sat...Se Winds 5 To 10 Kt With Gusts Up To 20 Kt. Waves 2 To 3 Ft. Rain Likely.|
|Sat Night...Ne Winds 10 To 15 Kt With Gusts Up To 25 Kt. Waves 2 To 3 Ft, Except 4 To 6 Ft At The Bay Entrance. A Chance Of Rain.|
|Sun...Nw Winds 10 To 15 Kt With Gusts Up To 25 Kt. Waves 2 To 3 Ft, Except 4 To 6 Ft At The Bay Entrance. A Chance Of Showers.|
|Sun Night...W Winds 10 To 15 Kt With Gusts Up To 20 Kt. Waves 2 To 3 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
104pm EST Wednesday Dec 2 2020
Seasonable temperatures today and cannot rule out a scattered rain shower across much of the region today. Could see a snow shower across the higher elevation of the interior. Dry and milder Thursday then a few showers are possible Friday as a weak disturbance moves through. There is the potential for a storm impacting the region Saturday into Saturday night with mostly rain for southern New England but may end as some snow over higher elevations. The storm exits Sunday, then mainly dry and colder weather Monday and Tuesday.
Near Term - Until 6pm This Evening
Forecast remains on track. Have made minor adjustments to sky cover to bring the forecast closer to the latest observations.
Increased precipitation chances across much of southern New England. A trough is lifting through at the base of the cutoff low. Given this in combination with diurnal heating and -30 to -20 degree Celsius 500 hPa air aloft. Will have isolated to scattered rain and snow showers across the interior today. Best shot for snow showers is across the higher elevations. Should be rain elsewhere. Have nudged the forecast toward the HRRRE and HREF guidance, which covers a bit more of southern New England compared to the previous forecast. Not expecting a washout, but could see a passing shower or two especially this afternoon. Cape and Islands have ocean effect rain chances continue through the day.
Rest of the forecast is on track.
Deep mid level trough across New York state with scattered snow showers in the vicinity of the trough axis. As the trough and accompanying shortwave energy slides east across New Eng today, expect a few snow/rain showers to move into interior SNE, especially northern and western MA. Meanwhile ocean effect clouds are moving across the Cape/Islands. Delta T from SST to top of the boundary layer is near 20C south of New Eng so expect a few rain showers to develop south of the coast. With SW trajectory, a few showers may impact portions of the Cape/Islands this afternoon. Otherwise, a mix of sun and clouds expected today.
850 mb temps around -8C today. This will support highs ranging from upper 30s higher terrain to mid 40s along the south coast. Gusty SW winds along the immediate south coast and especially Cape/Islands where occasional gusts to 25-30 mph.
Short Term - 6pm This Evening Through 6pm Thursday
Tonight... Diminishing winds and clearing skies should allow for a rather decent radiational cooling night. Expect most interior locations to fall into the 20s, except for areas along the immediate South Coast and the Cape and Islands where the mixed layer does not decouple. Have trended overnight lows towards the 25th percentile but it's not out of the question we could trend overnight lows even colder towards the low 20s if winds completely decouple in the usual radiational cooling hot spots in the interior.
Thursday... As the upper low moves off to the north, the flow over New England becomes briefly more zonal with weak surface high pressure building in from the Mid Atlantic region. Expect dry weather with sun and mixing, and mixing to 925 mb would support max temps in the mid 40s to low 50s. By the afternoon hours, expect increasing high cirrus coverage thanks to a shortwave being ejected by a closed low over the Oklahoma/Texas Panhandle region.
Long Term - Thursday Night Through Tuesday
Highlights... * A few showers possible Fri * A storm brings mostly rain Sat/Sat night, possibly ending as snow higher terrain * Improving conditions Sunday, then mainly dry and turning colder early next week
Thursday night into Friday... Northern stream trough digs across the Gt Lakes with multiple shortwaves tracking to the north of SNE through Friday. Meanwhile, 120 kt upper level jet lifts north across SNE during Fri. Thu night will be dry, then a deepening moisture axis will develop ahead of the trough on Fri and moving into SNE which may bring a few showers under the upper jet. Axis of moisture and potential showers is not certain but consensus of guidance favor interior locations for a few showers Fri afternoon. Mild temps in the upper 40s to mid 50s with gusty SW winds at times.
Friday night into Sunday... Forecast confidence decreases in this period due to uncertainty with timing, track and intensity of a potential storm. Rather complex pattern with split flow and multiple northern and southern stream shortwaves interacting with each other. Lots of moving parts and significant spread exists among deterministic and ensemble guidance. It will likely take another few days before model guidance can get a better handle on how this plays out. A storm is likely but timing and details are uncertain. Lack of initial cold air and guidance favoring an inside runner suggests a mostly rain event for SNE with possible changeover to snow over the higher terrain on the backside of the storm. Storm may be exiting by Sunday with improving conditions but changes to timing and precipitation type/amounts are possible as we move closer to the event. Latest ensemble guidance suggesting only a moderate wind event but this will depend on the intensity and track of the storm which remains uncertain.
Monday and Tuesday... Low confidence forecast. Consensus of the guidance favors mostly dry and colder weather with below normal temps, but still a lot of spread in the upper air pattern which features an amplified mean trough across the eastern US, but several shortwaves rotating through the flow in the northern and southern streams. It remains a chaotic pattern which is impossible to resolve at this time range so changes in the forecast are likely.
Small Craft Advisories continue for all waters today except for Boston Harbor and Narragansett Bay. This is due to SW winds at 15-25 kts with gusts 25-30 kts as well as 5-10 ft seas for the open waters. There may also be scattered showers for waters off the south coast and the Cape and Islands during the day today. Winds shift to the W Wednesday night with 10-20 kt winds and gusts of 20-30 kts.
Outlook /Thursday Night through Sunday/... Thursday Night: Low risk for Small Craft Advisory winds with gusts up to 20 kt. Seas up to 5 ft.
Friday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft.
Friday Night through Saturday: Winds less than 25 kt. Seas up to 5 ft. Rain likely.
Saturday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 11 ft. Chance of rain.
Sunday: Moderate risk for Small Craft Advisory winds with areas of gusts up to 30 kt. Rough seas up to 12 ft. Chance of rain showers.
NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None.
Small Craft Advisory until 7am EST Thursday for ANZ231>235- 237-251. Small Craft Advisory until 7pm EST Thursday for ANZ250- 254>256.