Marine Weather Net

Boston Harbor Marine Forecast


THIS AFTERNOON

SE
WINDS
5 - 10
KNOTS

TONIGHT

S
WINDS
5 - 10
KNOTS

SUN

SW
WINDS
5 - 10
KNOTS

SUN NIGHT

SW
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
ANZ230 Forecast Issued: 108 PM EDT Sat May 21 2022

This Afternoon...Se Winds 5 To 10 Kt. Waves 1 Foot Or Less.
Tonight...S Winds 5 To 10 Kt, Becoming Sw After Midnight. Waves 1 Foot Or Less.
Sun...Sw Winds 5 To 10 Kt, Becoming S 10 To 15 Kt With Gusts Up To 25 Kt In The Afternoon. Waves Around 2 Ft.
Sun Night...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt, Becoming Nw After Midnight. Waves Around 2 Ft.
Mon And Mon Night...N Winds 5 To 10 Kt. Waves 1 Foot Or Less.
Tue Through Wed...E Winds 5 To 10 Kt With Gusts Up To 20 Kt. Waves 2 To 3 Ft.
Wed Night...S Winds 5 To 10 Kt. Waves 1 Foot Or Less. A Chance Of Showers. 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
210pm EDT Sat May 21 2022

Synopsis
Mid summer heat and increasing humidity for the weekend. A few stronger thunderstorms could develop late Sunday afternoon in western areas of southern New England. Showers will accompany a cold front Sunday night. The first half of next week will feature seasonable temperatures and dry weather, with the weather turning unsettled for late next week.

Near Term - Until 6pm This Evening
205 PM

Most of the low clouds have burned off across our region as of early afternoon. While the low clouds this morning have kept temps in check; they will jump over the next few hours with the sun emerging. Many locations should still see highs in the upper 80s and lower 90s. The exception will be along the immediate coast; where high temps will be held in the 70s to near 80 given the sea breeze. Heat Indices will also respond and rise into the middle 90s with a few spots peaking in the upper 90s.

Despite an EML present along with impressive instability this afternoon; upper level ridging and capping inversion should keep us generally dry. Low risk for a few brief showers/t-storms this evening across northwest MA, but that is a worst case scenario.

Short Term - 6pm This Evening Through Sunday Night

315 am

00z suite doesn't show anything different from what we had already going. So my forecast edits were rather minimal. Most areas will not cool off much overnight with lows of 65-70F in many areas -- perhaps low-mid 70s for some urban centers. Expect another round of late night patchy fog and stratus, however southwest winds just above the surface will be strengthening overnight so this should keep the area impacted much less, perhaps just the immediate south coastal areas, Cape and Islands.

Sunday will be another hot day. Guidance suggest the 850mb and 925mb temperatures will be 1-2C warmer. Given plenty of sunshine, it's pretty much take today's highs and add a degree or two. So lots more mid-90s for highs, and another day with daily record highs being set. What will be different on Sunday is deeper mixing in the boundary layer, which will result in slightly lower dewpoints in the afternoon (lower-mid 60s) and tapping into some stronger winds aloft. Thus the afternoon should give us frequent gusts of 20-25mph or perhaps a bit higher. So despite slightly warmer temperatures, lower dewpoints will result in very similar heat index values and some wind may make it more bearable. Still hot is hot, and the Heat Advisory will continue. The stronger winds will also keep a sea breeze from forming, so the immediate east coast will have temperatures rise above 90F. Only the immediate south coast of RI/MA and Cape/Islands will get the cooling from the ocean waters.

Very late in the afternoon we may see some stronger thunderstorms roll into far western sections of MA and CT. Looks to be a very good setup for severe weather just to our west, however the timing may be a little too late in the day for us to get in on the biggest storms. Storm Prediction Center did trim their slight risk area slightly to the west, and based on the 00z guidance, that seems reasonable. However if the models are just 3 hours too slow, we could see some hefty t-storms in more of southern New England in that 4-8pm timeframe. Kept the mention of gusty winds/small hail.

Long Term - Monday Through Friday
Highlights... * Cold front arrives later Sunday with the chance for showers and thunderstorms, some of which may be strong. * More seasonable temperatures return for the new work week with lower dew points and onshore flow. * Turning warmer and unsettled again by late week.

Details... Sunday night... Cold front crosses the area later Sunday. Due to less mid-level instability and weaker lapse rates, while there is a risk for thunder, the potential for strong storms should quickly diminish with sunset. In other words, expect mainly garden-variety isolated thunderstorms on Sunday evening with the main risks being brief gusty wind, small hail and local downpours. Sunday overnight lows will range from upper 50s in western zones to lower to mid 60s in the eastern zones (except for upper 60s in the urban heat islands). Following coordination with SPC, the slight and marginal severe risks have been trimmed further west given the conditional nature of the storms. Nonetheless, something to watch if you have outdoor plans Sunday evening as any storms that fire up could become severe quickly.

Monday into Friday... Monday highs will be about 5 degrees above normal but a lot more seasonable and a lot more comfortable with dew points falling into the 40s to near 50. Expect mostly dry conditions with mix of sun and clouds on Monday although there could be lingering showers around, especially across southeast MA.

Indeed, a much more seasonable air mass will dominate Tuesday through mid week, with a broad ridge of high pressure over Canada leading to onshore flow for most days. Then a warming trend towards the latter half of the work week as low-level flow becomes more southerly and eventually southwesterly. Expect temps to return to above normal. For reference, average highs for late May are in the low to mid 70s. So upper 70s to low 80s make a return by late week. In addition, showers and thunderstorms make a return to the forecast but plenty of uncertainty remains with regards to the timing. So mainly stuck to a blend of guidance for this time period. Overall, pretty benign weather pattern to finish off meteorological spring!

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

300 am

High confidence in the forecast.

Primary concerns for the marine areas will be the areas of fog, some of which will be locally dense. Should see some improvement this afternoon, but fog/low clouds will redevelop this evening and last overnight. On Sunday the fog should dissipate across the waters off the eastern coast of MA, however areas of fog may persist around the islands and south of RI and MA. A cold front will move through the waters Sunday night, possibly bringing a few showers or a thunderstorm. Southwest winds will continue through the weekend, although generally in the 10-15kt range. As a result, seas are expected to remain less than 4 feet.

Outlook /Monday through Wednesday/... Monday through Monday Night: Winds less than 25 kt. Areas of seas approaching 5 ft.
Tuesday: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers, isolated thunderstorms.

Tuesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers, isolated thunderstorms.

Wednesday: Winds less than 25 kt. Seas up to 5 ft.

Climate
Daily record high temperatures... Sat May 21st... BOS 93F (1921) PVD 93F (1996) BDL 93F (1996) ORH 88F (1975)

Sunday May 22nd... BOS 93F (1959) PVD 94F (1941, 1992) BDL 95F (1992) ORH 90F (1911, 1992)

Monthly record high temperatures... BOS 97F (05/26/1880) PVD 96F (05/26/2010) BDL 99F (05/26/2010, 05/20/1996) ORH 94F (05/26/2010)

NOAA Boston MA Office: Watches - Warnings - Advisories
CT...
Air Quality Alert until 11pm EDT this evening for CTZ002.
Heat Advisory until 8pm EDT Sunday for CTZ002>004. MA...
Heat Advisory until 8pm EDT Sunday for MAZ003>006-010>018-026. RI...
Air Quality Alert until 11pm EDT this evening for RIZ001>008.
Heat Advisory until 8pm EDT Sunday for RIZ001>004.

Marine
None.