Marine Weather Net

Rhode Island Sound Marine Forecast


15 - 20


10 - 15


5 - 10



The Marine Weather Forecast In Detail:
ANZ235 Forecast Issued: 701 AM EDT Sun Mar 26 2023

Today...W Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 4 To 6 Ft. Patchy Fog This Morning With Vsby 1 Nm Or Less.
Tonight...W Winds 10 To 15 Kt With Gusts Up To 25 Kt, Diminishing To 5 To 10 Kt After Midnight. Seas 4 To 6 Ft.
Mon...W Winds 5 To 10 Kt, Becoming S In The Afternoon. Seas 2 To 4 Ft.
Mon Night...Se Winds Around 5 Kt, Becoming N After Midnight. Seas Around 2 Ft. Rain Likely.
Tue...N Winds 5 To 10 Kt. Seas Around 2 Ft. A Chance Of Rain.
Tue Night...Sw Winds 5 To 10 Kt, Becoming N 10 To 15 Kt After Midnight. Seas Around 2 Ft.
Wed Through Thu Night...Nw Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 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.
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Area Forecast Discussion
National Weather Service Boston/Norton MA
720am EDT Sunday Mar 26 2023

Dry and mild weather today but with a gusty wind. High pressure builds in tonight with clear and cold conditions. The next system brings rain and snow late on Monday into Tuesday as low pressure tracks south of New England. Appears drier Wednesday through Thursday as high pressure nudges in. Unsettled late in the week and heading into the weekend.

Near Term - Until 6pm This Evening
715 AM

Increased cloud cover for the next 2-3 hrs as there is a bit more stratus in place than previous shift indicated. Should see this lift quickly as the sun comes up and westerly winds pick up. On top of this any areas of fog or dense fog will lift as well. Should see plenty of sunshine by roughly 9-10am across all of southern New England. Only potential exception is parts of the Cape/Nantucket/Marthas Vineyard.

Previous discussion... Weak low pressure in vicinity of Buzzards Bay lifts NE into Gulf of Maine by daybreak with wind shift to west. The wind shift will advect low level dry drier air into SNE which will result in stratus lifting and partial clearing around daybreak, although the low clouds could linger a few more hours over outer Cape and Nantucket.

Low amplitude upper trough axis will be over New England today with residual cold pool(a region of relatively cold air) aloft. 500 mb temps around -25C combined with shallow low level moisture will lead to sct-bkn strato-cu developing this morning, with most coverage across northern MA, but expect decreasing cloud cover here mid/late afternoon as moisture diminishes. Otherwise, mostly sunny day for rest of the region. Soundings show a well mixed boundary layer up to about 850 mb so expect gusty winds developing with WNW gusts to 25-35 mph and up to 40 mph over the higher elevations. Temps at 850 mb this afternoon 0 to -4C from S to N which support highs ranging from upper 40s higher terrain to upper 50s across CT/RI and SE MA.

Short Term - 6pm This Evening Through 6pm Monday

Tonight... High pressure builds in from the west tonight. Dry airmass with clear skies and diminishing wind will lead good radiational cooling overnight. Leaned toward colder MOS guidance for low temps, generally mid/upper 20s western MA to 30-35 elsewhere.

Monday... Fast moving flow aloft will bring next shortwave toward New England from the Ohio Valley. Sunshine to start the day, then clouds increase and thicken in the afternoon. Much of the guidance has trended quicker and more aggressive with precipitation developing and moving into SNE late in the day as deepening moisture plume moves in from the west ahead of the shortwave. We introduced Probability of Precipitation across SW half of SNE but forecast confidence lower than what we would like for a day 2 forecast given the inconsistency among the guidance suite. While temps aloft are cold, boundary layer is too warm and supports rain but transitioning to snow toward evening over the higher elevations.

Long Term - Monday Night Through Saturday
Highlights... * Rain changing over to snow across the interior late Monday into early Tue. Elsewhere will be a cold rain. Light accumulations possible across the higher terrain. Precip tapers off late Tue. Low confidence in the forecast.

* Drier on Wednesday before a cold front crosses the region late Wednesday into Thu. Drier late Thu into early Fri.

* Unsettled late in the week and heading into the weekend.

* Temps will be near to above normal for much of the week.

Monday night through Tuesday... A shortwave trough will be over the Mid Atlantic late on Mon. The trough will lift offshore by early Tue. Another shortwave will lift quickly in behind the departing trough from the OH Valley into Tuesday before moving offshore late in the day. In response to these features a low moves from the Mid Atlantic to south of our region before moving offshore.

Confidence in this particular period is lower than would like especially given we are talking the Day 2.5-3 window. There has been considerable uncertainty in deterministic and ensemble guidance over the past several days. This is essentially due to guidance having trouble handling convective activity over the Southeastern US and OH Valley and its interaction with the troughs. This impacts the timing and intensity of the system as it moves through.

At this point the 00Z 12km NAM is a bit of an outlier being the slowest with much more Quantitative Precipitation Forecast and accumulating snow potential across our interior. Given the NAM 3km shows a more progressive feel like the GFS/ECMWF/GEM and explicitly resolves convection am thinking this is the main reason for the difference. Still will want to keep a close eye on how things evolve as there has been little run-to-run and model to model consistency. Did opt to bump up Quantitative Precipitation Forecast and snowfall amounts a bit given the shift in guidance. We've now got roughly 60- 100 percent probabilities of 24 hr Quantitative Precipitation Forecast at or above 0.1" per the GEFS/GEPS and EPS, which is a big jump from the previous. Due to this have bumped precipitation chances up to likely Monday night before gradually tapering chances off into early Tue. The corresponding 24 hr snow at or above 1" with a 10:1 SLR is roughly 10-70 percent heading into Tuesday AM. Looks like best chances are across the higher terrain at this point, but will be dependent on the precipitation timing/intensity. Stay tuned as hopefully models will come into better agreement later today or tonight.

Expect rain to change over to snow, but even mass fields are all over the place at this point. Have stuck toward the GFS/ECMWF/GEM consensus at this point, but there would be more accumulating snow if the heavier precipitation comes in later. Lows in the 30s across the region Monday night heading into Tue. Should see any lingering snow change back over to rain on Tuesday as precipitation is gradually winding down. High temps around seasonable with readings in the 40s to low 50s.

Late Tuesday through Wednesday... At this point guidance trending toward a drier forecast. A shortwave ridge builds from the Mid Atlantic/eastern Great Lakes late on Tuesday offshore by Wednesday AM, while a shortwave trough undercuts it and lifts from the Mid Atlantic offshore to the south of our region. A ridge builds across the Central US on Wed, while we remain under cyclonic flow. At this point appears that high pressure will nudge into our region from the OH/TN Valley through this period.

Guidance overall trending in a drier direction for this timeframe as high pressure builds in. Think this is the direction to go at this point, but there are several EPS members still featuring a coastal system of some sort. This is likely a result of more convective activity interacting with the trough undercutting the ridge. Given the uncertainty during the Mon-Tuesday window do not want to completely rule this out quite yet. For now have slight chances of precipitation with near to above seasonable temperatures.

Late Wednesday through Thursday... A trough lifts from the central Great Lakes/Ontario late on Wednesday into Quebec by early Thu. The ridge builds into the Mississippi River Valley and central Great Lakes. A cold front crosses the region as high pressure is nudging in from the Southeastern US.

Not out of the question the cold front could bring us some shower activity late on Wednesday into early Thu, but at this point have stuck with a drier forecast as high pressure remains over our region through Thu. Near seasonable temps expected.

Friday through Saturday... Have stuck with the NBM for this timeframe. This will be our next opportunity for more widespread rain showers and perhaps a few thunderstorms. Will have a trough lift from the Four Corners Region early on Fri into the Great Lakes by late Fri/Sat. This could also be our next opportunity for gusty winds as NAEFS shows winds of 2-3 STD above climatology during this period.

Forecaster Confidence Levels:

Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent.

Overall high confidence through Mon.

Small Craft Advisories posted for all waters for west wind gusts 25- 30 kt, developing this morning and persisting through the afternoon. Winds gradually diminish tonight as high pressure builds in from the west. Mostly light winds Monday under high pres.

Outlook /Monday Night through Thursday/... Monday Night: Winds less than 25 kt. Chance of rain.

Tuesday through Wednesday: Winds less than 25 kt. Slight chance of rain.

Wednesday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Slight chance of rain.

Thursday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft.

NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None.

Small Craft Advisory until 11pm EDT this evening for ANZ230. Small Craft Advisory until 8pm EDT this evening for ANZ231- 236. Small Craft Advisory until 8pm EDT this evening for ANZ232>234. Small Craft Advisory until 11pm EDT this evening for ANZ235- 237. Small Craft Advisory until 8am EDT Monday for ANZ250-254>256. Small Craft Advisory until 2am EDT Monday for ANZ251.