Marine Weather Net

Massachusetts Bay and Ipswich Bay Marine Forecast


TONIGHT

SW
WINDS
5 - 10
KNOTS

SUN

NW
WINDS
5 KNOTS

SUN NIGHT

S
WINDS
5 - 10
KNOTS

MON

SW
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
ANZ251 Forecast Issued: 703 PM EDT Sat Jul 13 2024

Tonight...Sw Winds 5 To 10 Kt, Becoming W After Midnight. Seas Around 2 Ft. Wave Detail: Se 2 Ft At 9 Seconds And Sw 1 Foot At 3 Seconds. Patchy Fog. Vsby 1 To 3 Nm After Midnight.
Sun...Nw Winds Around 5 Kt, Becoming Se In The Afternoon. Seas 1 Foot Or Less. Wave Detail: W 1 Foot At 2 Seconds And Se 1 Foot At 9 Seconds.
Sun Night...S Winds 5 To 10 Kt, Becoming Sw After Midnight. Seas Around 2 Ft. Wave Detail: Se 2 Ft At 5 Seconds And S 1 Foot At 2 Seconds.
Mon...Sw Winds 5 To 10 Kt, Becoming S 10 To 15 Kt In The Afternoon. Seas Around 2 Ft In The Morning, Then 1 Foot Or Less. Wave Detail: Se 2 Ft At 8 Seconds And Sw 1 Foot At 2 Seconds, Becoming S 1 Foot At 3 Seconds And Se 1 Foot At 8 Seconds.
Mon Night Through Tue Night...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas Around 2 Ft. Wave Detail: Se 2 Ft At 6 Seconds And S 1 Foot At 3 Seconds.
Wed...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas Around 2 Ft. Wave Detail: Sw 1 Foot At 3 Seconds And Se 1 Foot At 8 Seconds. A Chance Of Showers.
Wed Night And Thu...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt, Becoming W 5 To 10 Kt. Seas Around 2 Ft, Then 1 Foot Or Less. Showers Likely. Vsby 1 To 3 Nm.
Thu Night...W Winds 5 To 10 Kt. Seas 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
737pm EDT Sat July 13 2024

Synopsis
Widespread showers, and some downpours, move offshore this evening. Hot on Sunday, but slightly less humid with sunny skies. Hot and humid Monday through Wednesday, with the chance for afternoon thunderstorms Monday and Wednesday. Cold frontal passage late Wednesday/Thursday will give way to a much more comfortable airmass to end the work week.

Near Term - Through Sunday
7:45 PM

A weak, broken line of downpours and weak thunderstorms continues to very slowly work across southern New England; a few lightning producing cells have crept into far NE MA, which was well modeled by the ARW and NAMNest this evening. With instability waning after sunset, should see these storms die down quickly over the next hour or two, resulting in little more than a quick downpour for an one locality.

Previous

Canceled the rest of the Flood Watch, as the heaviest rainfall has moved farther offshore. Any lingering convection this evening should be isolated, and not particularly strong.

A nearly stationary front across souther New England should finally get pushed out to sea late tonight into Sunday. Humidity expected to drop slightly overnight, but still be quite muggy by New England standards. A risk for showers until midnight or so, but expecting coverage to really drop off after sunset given the weak dynamics in place.

Short Term - Sunday Night
Still expecting more of a mid level ridge and weak high pressure at the surface to our west. Expecting rain-free weather with slightly lower humidity. At least dew points should be mainly in the 60s away from the immediate coast. A little reprieve from the tropical humidity we have been experiencing for most.

winds expected to generally be light W to NW. This light flow should result in seabreezes along the coast. Even so, expecting high temperatures to be higher tomorrow given the lower humidity and more sunshine.

Long Term - Monday Through Saturday
* Another round of dangerous heat and humidity builds into the region Monday through Wednesday with the potential for scattered thunderstorms and showers

* Cold frontal passage Wednesday night/Thursday will bring relief from the heat

* More comfortable dewpoints and seasonable temperatures by next weekend

Monday through Wednesday... Southern New England remains nestled between high pressure across the Atlantic and broad trough across Quebec/Ontario that very slowly drops south into the Great Lakes early next week. This pattern results in a prolonged period of muggy, hot conditions with 850mb temperatures ranging from 18 to 21C, supportive of widespread highs in the mid 90s away from the immediate coastline. On par with the previous forecast, heat looks to peak on Tuesday, where heat index values have the potential to climb in excess of 105-107F by mid afternoon. Given high confidence in the early week heat, elected to hoist a Heat Advisory for much of the region away from the coast and outside the high terrain on Monday, with a more expansive Excessive Heat Watch in place for Tuesday (which only excludes the Cape and Islands). Given heat on Wednesday will be dependent on the timing of, the later mentioned, cold front, elected to leave the decision on a watch up to later shifts.

Minor shortwave feature looks to develop the second half of Monday in the vicinity of Lake Erie and shifts east across New England by afternoon. Given high instability, SBCAPE potentially exceeding 2000J/kg, in place driven by the heat and humidity, lift provided by the shortwave may be enough to generate some pop up afternoon thunderstorms, particularly across interior MA. As with most of our convection, timing of storm development will be critical with instability falling off quickly after sunset. Mid level lapse rates look so-so, around 6-6.5C/km, so even as instability wanes a residual EML may be able to keep storms alive a few hours past 00Z. Instability remains high again on Tuesday but with less forcing, shower/thunderstorm activity looks to be much more isolated.

Trough digs deeper into the Ohio River Valley by late Wednesday evening/Thursday and resulting cold front will likely generate our best chance for widespread precipitation/Thunderstorm activity on Wednesday evening.

Thursday and Beyond... Airmass behind the cold front will be quite refreshing, so while there is potential for some lingering showers Thursday morning, dewpoints will fall into the upper 50s/low 60s with highs in the upper 70s/low 80s to round out the work week and begin the weekend. This will be quite a welcome change for many across southern New England give the prolonged period of 65F+ dewpoints the region has experienced over the last several weeks.

Marine
Forecaster Confidence Levels:

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

A front moves offshore late tonight into Sunday, with high pressure to follow late Sunday into Sunday night. Showers and fog this evening and overnight with occasionally lower visibility around 1 mile. Improving visibility with rain-free conditions Sunday and Sunday night.

Outlook /Monday through Thursday/... Monday: Winds less than 25 kt.

Monday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers.
Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Tuesday Night: Winds less than 25 kt. Seas up to 5 ft.

Wednesday: Low risk for Small Craft Advisory winds with gusts up to 20 kt. Seas up to 5 ft. Slight chance of rain showers, isolated thunderstorms.

Wednesday Night: Winds less than 25 kt. Local rough seas. Rain showers likely, isolated thunderstorms.

Thursday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers, isolated thunderstorms.

NOAA Boston MA Office: Watches - Warnings - Advisories
CT...
Heat Advisory from 8am to 8pm EDT Monday for CTZ002>004. Excessive Heat Watch from Tuesday morning through Tuesday evening for CTZ002>004. MA...
Heat Advisory from 8am to 8pm EDT Monday for MAZ003-005>007- 010>015-017>019-026. Excessive Heat Watch from Tuesday morning through Tuesday evening for MAZ002>021-026. RI...
Heat Advisory from 8am to 8pm EDT Monday for RIZ001>004. Excessive Heat Watch from Tuesday morning through Tuesday evening for RIZ001>004-006-007.

Marine
None.