Marine Weather Net

Boston Harbor Marine Forecast


10 - 15


5 - 10




5 - 10

The Marine Weather Forecast In Detail:
ANZ230 Forecast Issued: 704 AM EDT Fri Jun 14 2024

Today...Sw Winds 10 To 15 Kt With Gusts Up To 25 Kt. Waves Around 2 Ft. Showers Likely With Scattered Tstms This Afternoon. Some Tstms May Produce Damaging Winds, Frequent Lightning, And Heavy Rainfall This Afternoon.
Tonight...Sw Winds 5 To 10 Kt, Becoming Nw After Midnight. Waves 1 Foot Or Less. Showers Likely. Scattered Tstms In The Evening. Some Tstms May Produce Damaging Winds, Frequent Lightning, And Heavy Rainfall In The Evening.
Sat...N Winds Around 10 Kt, Becoming Ne In The Afternoon. Waves Around 2 Ft In The Morning, Then 1 Foot Or Less. A Chance Of Showers.
Sat Night...N Winds 5 To 10 Kt. Waves 1 Foot Or Less, Then Around 2 Ft After Midnight.
Sun...N Winds 5 To 10 Kt, Becoming E In The Afternoon. Waves 1 Foot Or Less.
Sun Night...S Winds 5 To 10 Kt, Becoming Sw After Midnight. Waves 1 Foot Or Less.
Mon Through Tue Night...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Waves Around 2 Ft. Winds And Waves Higher In And Near Tstms. 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
708am EDT Fri Jun 14 2024

Warm and muggy today with scattered showers and thunderstorms this afternoon and evening...some of which may be severe mainly northwest of I-95. A few lingering spot showers are possible early Saturday...otherwise high pressure brings dry and beautiful weather for the weekend with low humidity. A warm- up begins on Monday with an extended period of excessive heat and humidity possible beginning Tuesday and continuing through Friday.

Near Term - Until 6pm This Evening
705 AM

Key Points

* Warm and muggy start to the day * Scattered severe thunderstorms mainly NW of I-95

Previous forecast remains on track. Main concern continues to revolve around the threat for scattered severe thunderstorms this afternoon and evening with the main risk northwest of I-95. Timing of the convection remains tricky...but appears we may have two rounds. The first in the noon to 5 pm range on a pre- frontal trough and perhaps a second round as the shortwave approaches early this evening. Prior forecast discusses this all below.

Today will be a warm and humid day with temperatures quickly rising into the mid to upper 80s and dew points reaching the mid to upper 60s. This will help set the stage for scattered severe thunderstorms as a potent shortwave trough and cold front drops SE across the region in the afternoon. As the cold front moves through, a very narrow corridor of instability will be set up across western MA and CT. There continues to be some disagreement among the hi-res HREF guidance on how much instability will be available mainly due to timing differences on convective development. HREF mean shows near 1000 J/kg of SBCAPE with the 90th percentile showing around 2000 J/kg. With deep layer shear approaching 30-40 knots, the environment will be supportive of organized clusters of severe thunderstorms. Initiation remains a bit uncertain with some members of the HREF initiating storms shortly after 12pm, while others holding off as late as 4pm. latest 06z guidance is trending towards a faster solution with height falls from the shortwave arriving earlier in afternoon. Storms likely initiate off the high terrain in Western MA/CT and southern VT/NH then move ESE through the afternoon. Storms should quickly weaken as the approach eastern MA and RI as they run into a more stable environment with less instability and shear. The severe threat at this time looks highest north and west of the I-95 corridor as highlighted by the Storm Prediction Center slight risk.

Severe threats:

The primary severe threat will be strong to damaging winds with steep low level lapse rates, DCAPE values near 700 J/kg, and linear storm mode promoting straight line winds. The hail threat has increased since yesterday due to models steepening mid level lapse rates to 6-7 C/km. The freezing level still remains above 10kft which should help to melt most hail before reaching the surface. The tornado threat remains very low at this time with 0-3km SRH around 100 m/s and the Sig Tor parameter well less then 1.0. Storm mode also appears to favor linear clusters with upscale growth. Not completely out of the question that a discreet supercell could form at initiation before merging with other cells into line segments or clusters.

Heavy Rain Threat:

Although the storms will be progressive with little to no training expected, PWATs (Precipitable Waters) will be increasing into the 1.5-1.6 inches. CAPE profiles have become more fat and supportive of hail over the last 24 hours due to steepening mid level lapse rates. Warm cloud depths have also decreased to 8000ft. Despite these less favorable changes in the environmental parameters, the HREF 3hr PMM does still highligheights a small area in western MA and CT with 10% probs for greater then 3 inches of rain in 3 hours. This could lead to areas of street and poor drainage flooding along with isolated instances of flash flooding.

Short Term - 6pm This Evening Through 6pm Saturday


Thunderstorms quickly weaken into showers as they move east into less favorable environment and lose support from daytime heating. The shortwave axis crosses through the region overnight which will prolong the rain for eastern MA before tapering off by morning. Overnight lows stay on the warm side in the low 60s with overcast skies and rain.


Shortwave moves offshore with rising heigheights and high pressure beginning to build in for the weekend. There may be some lingering light showers in the morning in eastern MA, otherwise mainly dry conditions with clearing skies in the afternoon. Winds turn northerly advecting in cooler air for Saturday with highs only in the mid to upper 70s. Humidity will also be noticeably lower with dewpoints dropping into the 50s and even the 40s across the western interior.

Long Term - Saturday Night Through Thursday
Key Points... * Dry/cool Sat night followed by a beautiful Sunday with low humidity * Warmup begins on Monday with excessive heat & humidity Tuesday through Fri * Heat & Humidity Peak in the Wednesday through Fri time frame * Near Record Highs possible...Heat Indices between 95 & 104 at times

Details... Saturday night and Sunday..

Large high pressure will build over southern New England Sat night into Sun. A relatively dry airmass in place for mid June standards...coupled with mainly clear skies/light winds will yield a good night of radiational cooling. Overnight lows should bottom out in the 40s across the outlying locations with 50s in the urban centers. Plenty of sunshine on Sunday will allow for a beautiful day along with low humidity. Highs will be well up into the 70s to perhaps near 80 in a few spots.

Next Week... Confidence continues to grow in excessive heat and humidity next week. An anomalous upper level ridge will build northward into southern New England next week. A warming trend begins on Monday, but the significant heat/humidity potential looks to begin Tuesday and peak in the Wednesday through Fri time frame.

There has been a strong signal amongst all the model guidance for the last several days. The EPS/NAEFS situational awareness table indicates parameters outside the models climatology which is signal for the potential of a highly anomalous this case heat & humidity. Near record high temperatures will be possible. There are fairly high probs of temps reaching well into the 90s for a couple days and perhaps flirting with 100 degrees in some spots. Afternoon heat indices in the 95 to 104 degree range are possible at times. It will remain quite muggy at night so that will be another concern.

Strong upper level ridging in place will promote mainly dry weather for much of next week. That being said...near record heat may trigger the risk of a few t-storms at times but given lack of synoptic scale forcing dry weather will dominate.

Forecaster Confidence Levels:

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


Increasing SW winds gusting up to 25 knots. A cold front will sweep across the waters this evening. Thunderstorms will form along this cold front inland this afternoon and weaken as they approach the waters. A couple storms could still reach the waters and bring strong wind gusts and lightning near the coastal waters this evening. Seas 2-4 feet.


Steady light to moderate rain with embedded thunder possible. Winds shift WNW and decrease to 5-10 knots overnight. Seas 2-3 feet.


Rain tapers off in the morning with clearing conditions in the afternoon. Winds turn north and gust 15 to 20mph. Seas 2-4 feet.

Outlook /Saturday Night through Tuesday/... Saturday Night: Winds less than 25 kt. Areas of seas approaching 5 ft.
Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.

Sunday Night through Tuesday: Winds less than 25 kt.


Daily Record High Temperatures... Tuesday, June 18th

BOS - 94F (1929) BDL - 95F (1994) PVD - 94F (1929) ORH - 93F (1929)

Wednesday, June 19th

BOS - 96F (1923) BDL - 95F (1995) PVD - 94F (1923) ORH - 93F (1923)

Thursday, June 20th

BOS - 98F (1953) BDL - 97F (2012) PVD - 95F (1941) ORH - 93F (1953)

Last Day of 100F (or greater)

BOS - 100F (07/24/2022) BDL - 100F (07/21/2019) PVD - 100F (07/28/2020) ORH - 102F (07/04/1911)

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

Small Craft Advisory until 8pm EDT this evening for ANZ230>237-251. Small Craft Advisory from 11am this morning to 11pm EDT this evening for ANZ250-254.