Rhode Island Sound Marine Forecast
|Today...W Winds 5 To 10 Kt. Seas 2 To 3 Ft.|
|Tonight...Ne Winds 10 To 15 Kt With Gusts Up To 20 Kt, Increasing To 25 To 30 Kt With Gusts Up To 40 Kt After Midnight. Seas 3 To 5 Ft. Snow. Vsby 1 Nm Or Less.|
|Sat...N Winds 30 To 40 Kt With Gusts Up To 60 Kt. Seas 7 To 10 Ft. Snow. Vsby 1 Nm Or Less.|
|Sat Night...Nw Winds 25 To 35 Kt With Gusts Up To 50 Kt, Diminishing To 20 To 25 Kt With Gusts Up To 35 Kt After Midnight. Seas 6 To 9 Ft. Snow Likely. Vsby 1 Nm Or Less.|
|Sun...Nw Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 4 To 7 Ft. A Chance Of Light Freezing Spray.|
|Sun Night...Nw Winds 10 To 15 Kt With Gusts Up To 20 Kt, Diminishing To 5 To 10 Kt After Midnight. Seas 2 To 4 Ft.|
|Mon Through Tue Night...Se Winds 10 To 15 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.|
| 427 AM EST Fri Jan 28 2022 |
Synopsis for Massachusetts and Rhode Island coastal waters - ANZ200
Arctic high pressure pushes east of the waters tonight. A cold front approaches the waters from the west Friday, then stalls Friday night over the southern New England waters. Saturday low pressure develops off the NC coast intensifying into a powerful storm as it tracks NE near the 40N/70W benchmark Saturday evening, then into the Maritimes Sunday. High pressure builds over New England early next week.
| Area Forecast Discussion|
National Weather Service Boston/Norton MA
640am EST Fri Jan 28 2022
A cold front moves through the region this afternoon, possibly accompanied by a few snow showers or flurries. A powerful winter storm will impact much of southern New England Saturday into Saturday evening, bringing heavy snow, blizzard conditions to the coast, possibly damaging winds and coastal flooding. Drier weather returns with below normal temperatures Sunday before a warm up next week.
Near Term - Until 6pm This Evening
The first push of light radar returns is exiting Cape Code at this hour, though with dewpoint depressions around 10 degrees and model soundings indicating a dry layer below 900 mb, not expecting to see much at the surface. The next wave of snow showers for wester MA/CT comes late morning/afternoon when the boundary layer moistens up a bit. Not expecting appreciable accumulation, however.
Previous Discussion... Overall quiet and relatively mild weather is expected today as high pressure exits to the east. Increasing moisture on SW flow is bringing clouds and light snow showers this morning ahead of a mid level trough. Marginal forcing for ascent from this trough together with convergence ahead of an approaching cold front is already leading to scattered light snow showers from Worcester to Cape Ann. This will continue off an on through early afternoon when the cold front drops through. Best chance of these showers will be over western MA and CT. Highs today will be warmer than yesterday, in the upper 20s to mid 30s.
Late tonight after midnight things will begin to ramp up ahead of our significant winter storm, the bulk of which comes on Saturday. The 500 mb trough over the Tennessee Valley moves over the Carolinas between 06 and 12Z spawning a low offshore that will rapidly deepen as it moves up just south of the 70/40 benchmark by sunrise. Guidance has come into much better agreement on this track, with the outlier GFS finally shifting back west substantially over the last 24 hours. While the greatest forcing and heavy snow won't start in earnest until after 5 to 7 am or so, light to moderate snow will move into the south coast around midnight and quickly spread north and west. Given a very cold column, snow-to-liquid ratios at or above 10:1, and Quantitative Precipitation Forecast 0.25" to 0.5" we'll be waking up to snowfall amounts of 2 to 5 inches centered over southeast MA.
Short Term - 6pm This Evening Through 6am Saturday
*** A powerful multi facet winter storm with blizzard conditions and near hurricane force winds to impact southern New England Saturday & Saturday evening ***
Overview... Explosive cyclogenesis occurs off the Mid Atlantic coast tonight, with an impressive ~40 mb pressure drop in 24 hrs, yielding a bomb cyclone of around a 965 mb low over the eastern MA waters Sat evening! 00z guidance trended west and is in somewhat better agreement than previous runs, however differences still exist. The 00z NAM (especially the 12km NAM) the deepest, slowest and farthest west solution of the 00z guidance. Therefore followed a non NAM model blend solution for this portion of the forecast.
Details... Heavy snow/Blizzard conditions... Intense cyclone developing along a highly baroclinic zone, coupled with very strong jet dynamics, dual upper level jet streak and a fire hose of Atlantic moisture, will result in very heavy snowfall across RI and eastern MA. Still some uncertainty on the westward extent of the heavy snow. However enough confidence to upgrade to warnings for the entire region, except western MA where a winter storm watch was issued, given this will be the back edge of the heavy snow. Farther east across RI and eastern MA, heaviest snow will fall during the day Sat and Sat evening, where snowfall rates of 2-4 inches per hour are possible at times across RI and eastern MA, yielding storm totals of 12-18" across this area. The highest totals will likely be realized across eastern MA including Boston,Cape Cod and Marthas Vineyard where 18-24 inches is likely, and a low prob of isolated amounts of up to 30" is possible. However still too early to say exactly where these mesoscale bands set up, usually just to the NW of the mid level low or mid level bent back warm front. It's possible this heavy band of snow may pivot as far west as eastern CT/RI into the Worcester Hills. SLR in this band will likely be on the order of 15-20 to 1, given strong forcing in the snow growth region. Still too early to pinpoint these mesoscale features at this time range. Other issue with these mesoscale bands, is there is usually considerably less snow on either side of the band. Thus, snow totals will vary somewhat from location to location. Issued a blizzard warning for the immediate coast, as this is the area of highest probability of heavy snow, strong winds and vsby near zero at times. It's possible the blizzard warning may need to expanded westward into RT-128 and RI. Will wait to see trends in 12z guidance. Thundersnow is possible on the nose of the dry slot, as intrusion of mid level dry air steepens lapse rates. Although, if the dry slot comes too far onshore, this would cut down on snow totals, which is possible across the Cape and Islands. Something we will have to watch. Considerable blowing and drifting snow will persist into Sat night even after the snow ends, in response to very strong NNW winds.
Strong to damaging winds... Impressive low level NNE jet of 75-85 kt traverse the region this afternoon. Model soundings indicate up to 65 kt gusts is possible from Cape Ann to Cape Cod including the Islands. Thus, it's possible a few locations gust to hurricane force 64 kt/74 mph! Therefore, tree damage and power outages are possible in this region this afternoon and early evening.
Dangerous cold... As storm intensifies, it will draw upon very cold air over NY state and northern New England, advecting this airmass southward. Thus temps will fall thru the teens with heavy snow falling this afternoon. Gusty NNE winds will yield wind chills between +5 to -10F. So not quite Wind Chill Advisory criteria, but given near white-out conditions at times, again, don't venture out if at all possible.
Coastal flooding... See coastal flooding section for discussion.
Long Term - Saturday Through Thursday
Highlights... * Quiet and increasingly mild weather to follow through most of the week.
Sunday the low center moves up through the maritimes, replaced quickly by a broad high pressure. This high lingers overhead through at least Tuesday bringing dry and sunny weather. Winds, though, will remain elevated on Sunday as we're sandwiched between the exiting low and incoming high. Bufkit soundings indicate winds gusting 15 to 25 mph for most. Next chance for some wet weather comes around Wednesday with a glancing blow from a low passing to our north, but this looks insignificant at the moment. The main story will be warming temperatures, peaking in the low 50s by Thursday.
Forecaster Confidence Levels.
Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.
*** Storm Warnings with near hurricane force gusts ***
Cold front sweeps across the waters with SSW winds in the morning becoming WNW in the afternoon. Other than a few scattered snow showers or flurries, dry weather and good vsby prevail.
A powerful coastal storm approaches from the southeast, with N winds turning NNE with gusts increasing to 30-40 kt by daybreak. Rough seas with outer waters increasing to 6-10 ft.
A very powerful coastal storm tracks just east of Nantucket and Cape Cod, with central pressure lowering to around 965 mb in the MA coastal waters Sat afternoon. Storm force NNE winds with a few gusts approaching hurricane force (64 kt/74 mph). Dangerous seas building 20 to 30 ft eastern MA waters. Vsby near zero at times in heavy snow.
Saturday Night: Strong NNW winds with gusts up to 55 kt. Rough seas up to 28 ft. Chance of snow. Areas of visibility 1 nm or less.
Outlook /Saturday through Tuesday/... Sunday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 16 ft. Chance of freezing spray.
Sunday Night: Winds less than 25 kt. Local rough seas.
Monday: Winds less than 25 kt. Seas locally approaching 5 ft.
Monday Night: Winds less than 25 kt.
Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Tides / Coastal Flooding
Two tide cycles will be impacted from this storm, Sat morning and Sat evening. However, as of now it appears the strongest wind and storm surge will occur around the time of low tide Sat afternoon, with a surge of 2 to 3 ft. If this timing holds, both tide cycles would likely experience widespread minor coastal flooding, with pockets of moderate flooding. Didn't have 50% confidence for widespread moderate coastal flooding, therefore held off on a coastal flood watch. However, day shift today will have to see how 12z guidance trends, especially regarding timing of strongest winds and surge.
NOAA Boston MA Office: Watches - Warnings - Advisories
CT...Winter Storm Warning from midnight tonight to midnight EST Saturday night for CTZ002>004. MA...Winter Storm Warning from midnight tonight to midnight EST Saturday night for MAZ003>006-010>014-017-018-020-021-024- 026. Blizzard Warning from 7am Saturday to 5am EST Sunday for MAZ007-015-016-019-022-023. Winter Storm Watch from late tonight through Saturday evening for MAZ002-008-009. RI...Winter Storm Warning from midnight tonight to midnight EST Saturday night for RIZ001>008.
Storm Warning from 4am Saturday to midnight EST Saturday night for ANZ230>237-250-251-254>256.