Marine Weather Net

Rhode Island Sound Marine Forecast


THIS AFTERNOON

SW
WINDS
10
KNOTS

TONIGHT

SW
WINDS
5 - 10
KNOTS

TUE

S
WINDS
5 - 10
KNOTS

TUE NIGHT

NE
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
ANZ235 Forecast Issued: 1016 AM EST Mon Feb 24 2020

This Afternoon...Sw Winds Around 10 Kt With Gusts Up To 20 Kt. Seas 2 To 3 Ft.
Tonight...Sw Winds 5 To 10 Kt. Gusts Up To 20 Kt After Midnight. Seas 2 To 3 Ft.
Tue...S Winds 5 To 10 Kt, Becoming Se In The Afternoon. Seas 2 To 3 Ft. Patchy Fog. A Chance Of Showers. Vsby 1 Nm Or Less.
Tue Night...Ne Winds 5 To 10 Kt, Increasing To 10 To 15 Kt With Gusts Up To 20 Kt After Midnight. Seas 3 To 5 Ft. Patchy Fog. A Chance Of Light Rain Or Patchy Drizzle. Vsby 1 Nm Or Less.
Wed...Ne Winds 10 To 15 Kt, Increasing To 15 To 20 Kt In The Afternoon. Gusts Up To 25 Kt. Seas 3 To 5 Ft. Patchy Fog. A Chance Of Rain Or Patchy Drizzle.
Wed Night...E Winds 15 To 20 Kt With Gusts Up To 35 Kt. Seas 4 To 7 Ft. Patchy Fog. Rain.
Thu...Sw Winds 20 To 25 Kt With Gusts Up To 30 Kt. Seas 5 To 8 Ft. Rain.
Thu Night...W Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 5 To 8 Ft.
Fri And Fri Night...W Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 4 To 7 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
130pm EST Monday Feb 24 2020

Synopsis
A mostly sunny and unseasonably mild afternoon is in store for the region today. A weak frontal boundary will drop south across our area Tuesday and then stall near the south coast. Cloudy conditions with light rain, drizzle and fog from a warm front Tuesday night into Wednesday. A stronger frontal system for Wednesday night into Thursday should produce a period of steady rain for most, with a potential for light accumulating wintry mix in the higher terrain of northwest Massachusetts. Turning colder and blustery late in the week into the weekend.

Near Term - Until 6pm This Evening
130PM

No major changes to the near term forecast as temperatures are well on track with many locations across Southern New England in the upper 50s to mid 60s. There are also SSW or S gusts of 15 to 20 knots as vertical mixing improves with rising surface temperatures. As expected, cooler temperatures can be found along the coast with ocean temperatures still in the mid 30s to low 40s. With a southerly wind direction, locations along Narragansett Bay are about 5 to 10 degrees cooler than just further inland. A case in point is Providence, RI, which is located along the Providence River just upstream of Narragansett Bay. As of 125PM, Providence is 10 degrees cooler than Boston, which is just 1 hour away. Enjoy the beautiful afternoon!

Previous discussion... No major changes to the forecast except to bump up afternoon highs by a degree or two given that many locations are already into the low to mid 50s. All the major guidances are struggling with how warm it can get given that it has been an anomalous winter with a lack of snow cover. A dry air mass, dry soil conditions and a higher sun angle in late Feb are all reasons to go warmer than the guidance. In fact, even the the percentile of guidance is not warm enough for this afternoon. Winds pick up later today and there may even be a sea breeze. If you are a warm weather fan, go take advantage of the nice weather if you can because it goes downhill from tomorrow.

Short Term - 6pm This Evening Through 6pm Tuesday
Tonight... A weak frontal boundary will slowly approach the region from the north tonight. The upper level flow will also turn more to the southwest, which will allow for an increase in clouds. Dry weather should prevail, but we can not rule out a few sprinkles/light showers developing near the south coast by daybreak. Given the increase in clouds, overnight low temperatures will be held mainly in the 30s to near 40.

Tuesday... A weak surface boundary will drop south into the region Tuesday and then stall near the south coast. Southwest flow aloft will result in plenty of cloudiness, but there also will be some low level dry air which should allow for some peeks of sunshine. We may see a few sprinkles/light showers especially late in the day towards the south coast and parts of western MA/CT. However, given the lack of strong forcing and dry air in the low levels of the atmosphere expect much of the day to be dry. While temperatures will not be as mild as today, thinking they still get into the 50s across most of the region with a mild start and some peeks of sunshine.

Long Term - Tuesday Night Through Sunday
Highlights... * Mainly very light rain or drizzle Tues night into early Wednesday with weak warm front.

* Continued cloudy with intervals of light rain, fog and drizzle Wed.

* Strong frontal system may bring a period of light accumulating wintry weather to the higher terrain in the Berkshires Wednesday night into early Thurs. Mainly steady rains elsewhere with strengthening E winds.

* Cold frontal passage Thurs with falling temperatures and blustery W winds.

* Below-avg temps and cold wind chills late in the week into the weekend. Coldest conditions Sat and Sun.

Details... Tuesday Night into Wednesday:

Warm front looks to progress northward across Southern New England Tuesday night into early Wednesday. This warm front will be moving northward into NE surface to low-level flow associated with shallow cold air/cold air damming pressure ridge across far northern MA into southern NH. On precipitation potential, moisture appears to be lacking with the warm front, with much of the deeper moisture remaining suppressed over the waters well south of Long Island. NAM/GFS forecast soundings also indicate the moisture that is available is fairly shallow and could be more drizzle as opposed to steady rain. Model Quantitative Precipitation Forecast forecasts vary as well but are between dry/trace to a tenth of an inch, so either way not looking at a washout. Lows in the mid to upper 30s.

Into Wed, most models show ridge/wedge of high pressure over southern NH/coastal ME building SW towards central CT/RI, with winds become more NE to ENE. This wedge of high pressure would be associated with shallow colder air draining SW in the NE/ENE flow. Given this, it remains a tough temperature forecast with most models showing diurnal trends in temps either slowly rising to hovering. Ended up following the NAM in terms of temperatures, which brings highs only in the upper 30s to mid 40s, though some upper 40s possible towards central CT into Kent and Washington Counties in RI. Nevertheless, Wednesday looks to be shaping up to be pretty gray and dreary most everywhere, with periods of light rain and areas of mist/fog at times. probability of precipitation will also tend to increase late in the day as secondary surface low initially over northern VA early Wednesday builds NE towards the Philly metro/central NJ area.

Wednesday Night into Thursday:

Most active period of weather remains centered around Wednesday night into the first part of Thurs. A strengthening surface low treks across Southern New England and interacts with an anomalous plume of deep moisture. This may lead to another period of light accumulating wintry weather primarily in the higher terrain of the Berkshires, as well as strengthening E/SE winds over the coastal and offshore waters. As the cold front moves through, winds to then shift to W Thurs afternoon with sharp cold advection leading to falling temps in the afternoon and increasingly breezy/blustery winds.

Expecting E/SE winds to become enhanced Wednesday night due to both isallobaric effects (e.g. a fairly stout pressure tendency rise/fall couplet shown in most available NWP) and a robust E/SE low-level jet which translates N across eastern MA thru the night. There is some level of uncertainty on how strong E winds may get given that the strength of this low-level jet varies. The coarser-res guidance such as the ECMWF (European Centre for Medium-Range Weather Forecasts) and GFS show 925 mb jet max of 40 to up to 50 kt, while the higher-res NAM is closer to 55-65 kt. While E wind gusts should pick up a bit over the land, strongest increase is out over the waters where the potential exists for gale-force gusts. Should be sub-Advisory gusts over land but could see a need for a Gale Watch on the outer waters if trends continue. Other effect the strengthening winds will have is that while the air mass over NH into ME isn't super cold, it should still draw shallow cooler air southward a bit quicker.

PoPs increase to Categorical levels Wednesday night and into early Thursday as the surface low moves across. Most areas are warm enough for plain rain with rain amounts a half to nearly an inch of Quantitative Precipitation Forecast. The one exception is in the eastern slopes of the Berkshires where initial rain may transition to FZRA then S/IP as temperatures cool. What the surface temperatures look like casts the greatest source of uncertainty on wintry accumulation amounts: a colder NAM solution would support wintry precipitation across a larger part of NW MA and into the Worcester Hills, while the GFS would indicate little to no significant wintry wx. An upslope component may help boost accumulations here as well. WPC does carry about 1-3" of snow for their Day-3 forecast for the east slopes of the Berkshires, which meshes well with current thinking here and will also show icing amounts of a trace to 0.05". This nominally is enough for an Advisory but don't quite have the confidence yet to go with one on this shift, given the sensitivity to what the surface temperatures look like. Nonetheless there may be some minor Thursam travel impact in this area due to light accumulations of wintry mix.

During the day on Thurs, expect a rapid decrease in Probability of Precipitation by around late morning to early afternoon. Daytime highs in the mid/upper 30s (low 30s in the Berks) in the interior to the low-mid 40s coastal plain. Second part of Thurs will feel a lot different than the first part of the day, as temperatures fall sharply as cold advection aloft starts to surge in; the cold air aloft will also promote increasingly breezy west winds (gusts to 30-40 mph). Most areas are in the 30s by Thursday evening.

Thursday Night through Sunday:

Pattern change towards colder than normal weather still looks on track to close the month of February. Coldest period again looks to be over the weekend, though 925-850 mb temperature trends in NWP (Numerical Weather Prediction) for the weekend are maybe a touch milder than yesterday. It also won't be nearly as blustery as Thurs night into Fri project to be.

For Thurs night thru Fri...cold advection aloft will contribute to steep lapse rates into the nighttime hrs with W/WNW wind gusts around 25-35 mph. Lows Thurs night in the teens to mid 20s, with morning wind chills of single digits to the teens. High temperatures in the mid 20s to mid/upper 30s on Friday, will lead to daytime wind chills in the teens to the 20s given forecast wind speeds. The gustiness may make conditions feel even colder, though.

Into Sat and Sun...925 mb temps are at their coldest during this period of time (around -13 to -15C). Should see highs each day in the low-mid 20s to around freezing, with lows single digits to the mid/upper teens. NW winds aren't quite as strong/gusty as late this week, but will still contribute to lowest wind chills near 0F in the interior high terrain, to the single digits to teens above zero.

Precip chances look low in this period. Much of that will be mainly from intervals of lake-effect SHSN streamers Thurs night into Fri into the CT Valley, and potentially ocean-effect SHSN though trajectories appear to favor the Islands (more NW then N/NE). We will need to see if there is any trough energy that can lead to coastal cyclogenesis. Fairly low- confidence prospect as the ECMWF is the only model really indicating this potential, but it's not out of the realm of possibility. Its 00z/24th run does show a cyclone near the benchmark Sat afternoon moving into the Gulf of Maine/Bay of Fundy thru the overnight; yesterday was far offshore and more into Sunday. Will continue to monitor, but at the moment this potential looks too low-prob to consider any increased messaging attm.

Marine
Today...High confidence. High pressure to our south will continue to move east and further away from the region today. The result will be SW winds of 10 to 15 knots with some gusts into the lower 20 knots by afternoon. While seas may get a bit choppy this afternoon expect conditions to generally remain below small craft thresholds.

Tonight...High confidence. A weak frontal boundary will slowly approach the waters. This will weaken the gradient and keep SW at 5 to 15 knots and conditions below small craft advisory thresholds.

Tuesday...High confidence. A weak cold front drops towards the south coast and then stalls for a bit. This will separate NE winds of 5 to 10 knots across our northern waters and ESE at the same speeds across our southern waters. Given the weak pressure gradient, winds/seas will remain below small craft thresholds.

Outlook /Tuesday Night through Friday/... Tuesday: Winds less than 25 kt. Chance of rain showers, patchy fog. Local visibility 1 nm or less.

Tuesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain, patchy drizzle, patchy fog.

Wednesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Chance of rain, patchy fog, patchy drizzle.

Wednesday Night: Low risk for gale force winds with gusts up to 40 kt. Rough seas up to 11 ft. Rain, patchy fog.

Thursday: Low risk for gale force winds with gusts up to 35 kt. Rough seas up to 12 ft. Rain likely.

Thursday Night: Low risk for gale force winds with gusts up to 35 kt. Rough seas up to 12 ft.

Friday: Moderate risk for Small Craft Advisory winds with areas of gusts up to 30 kt. Areas of rough seas. Local visibility 1 to 3 nm.

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