Groton, MA Marine Weather and Tide Forecast
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Marine Weather and Tide Forecast for Groton, MA

June 23, 2024 12:37 AM EDT (04:37 UTC) Change Location
Sunrise 5:08 AM   Sunset 8:30 PM
Moonrise 10:29 PM   Moonset 6:16 AM 
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NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION.

Marine Forecasts
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ANZ230 Boston Harbor- 1004 Pm Edt Sat Jun 22 2024

.small craft advisory in effect from Sunday afternoon through Sunday evening - .

Overnight - NE winds around 5 kt. Waves 1 foot or less. Patchy fog. A slight chance of showers, then a chance of showers. Vsby 1 to 3 nm, decreasing to 1 nm or less.

Sun - SE winds 5 to 10 kt, becoming S 15 to 20 kt with gusts up to 25 kt in the afternoon. Waves 1 foot or less, then around 2 ft in the afternoon. Patchy fog in the morning. A chance of showers in the morning with vsby 1 nm or less.

Sun night - SW winds 15 to 20 kt, diminishing to 10 to 15 kt after midnight. Gusts up to 25 kt. Waves around 2 ft. A chance of showers.

Mon - W winds around 10 kt. Gusts up to 20 kt in the afternoon. Waves around 2 ft. A chance of showers in the afternoon.

Mon night - NW winds 5 to 10 kt. Waves 1 foot or less. A chance of showers in the evening.

Tue and Tue night - SW winds 5 to 10 kt. Waves around 2 ft.

Wed - SW winds 10 to 15 kt with gusts up to 25 kt. Waves around 2 ft.

Wed night - SW winds 10 to 15 kt with gusts up to 25 kt. Waves around 2 ft. Showers likely with a chance of tstms.

Thu - NW winds 5 to 10 kt. Waves 1 foot or less. Showers likely.

Thu night - N winds 5 to 10 kt. Waves 1 foot or less. A chance of showers.
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.

ANZ200 1004 Pm Edt Sat Jun 22 2024

Synopsis for massachusetts and rhode island coastal waters - High pressure to the south of new england will result in southwest winds across the waters this weekend. A cold front moves across new england Monday. High pressure builds back in on Tuesday, then slides offshore midweek, followed by another frontal passage Thursday.


7 Day Forecast for Marine Location Near Groton, MA
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Area Discussion for - Boston, MA
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FXUS61 KBOX 230212 AFDBOX

Area Forecast Discussion National Weather Service Boston/Norton MA 1012 PM EDT Sat Jun 22 2024

SYNOPSIS
Warm and muggy into Sunday with more rounds of diurnal showers and thunderstorms, with the focus across western and central MA Sunday afternoon. Some storms may again become severe and result in a localized flash flood threat. A few diurnally driven showers will remain possible Monday with but lowering humidity.
Dry and very warm weather is on tap for Tuesday but with lower humidity. Hot and humid weather returns later Wednesday. Another round of showers and thunderstorms is possible late Wednesday, perhaps lingering into Thursday
Otherwise
drier weather with lower humidity returns by Friday.

NEAR TERM /UNTIL 6 AM SUNDAY MORNING/

10 PM update...

Somewhat of an atypical setup for late June across SNE late this evening, with cool/stable NE flow covering much of the region along with temps in the 60s. The backdoor front is currently across central/western CT this evening. Upstream across NY state, convection is firing with cooling cloud tops and plenty of lightning. This is in response to strong mid level WAA ahead of short wave trough moving across the eastern Great lakes. The leading edge of this warmer air is denoted by a mid level warm front, in vicinity of where the convection is currently firing. This WAA pattern approaching from the west, combined with shallow cool/stable airmass over SNE, will provide an ideal overrunning setup overnight, again somewhat atypical for late June. Nonetheless, this convection over NY state will likely survive its trek into SNE, albeit in a weaken state with non-severe storms impacting CT/RI/MA overnight. Given elevated instability and high PWAT air, main issue will be heavy downpours. As the mid and low level flow becomes SW overnight and especially toward Sunday morning, this will lift the backdoor over CT northward as warm front overnight. Otherwise, previous forecast remains on track, thus, not expecting any wholesale changes with this update. Earlier discussion below.

================================================================

Key Points...

* Warm and muggy conditions continue tonight * Chance for elevated showers and thunderstorms overnight

Ongoing convection across western portions of SNE will weaken tonight as it moves east into a less favorable environment and come to an end between 8pm-12pm tonight. After 12pm tonight, there is considerable uncertainty on how things evolve overnight. Some of the Hi-res CAMS, mainly the HRRR, show scattered to widespread elevated convection overnight firing off a 30-40 knot LLJ and some elevated instability around 500 J/kg. Most of the other Hi-res CAMS keep the region dry or show only isolated convection. Overnight convection can be tricky as models generally struggle with it. Capped POPs below 40% across the region for the overnight period.

Warm and muggy still overnight with lows only in the mid to upper 60s, to even low 70s. Dewpoints also in the mid to upper 60s will keep conditions saturated allowing for low clouds and patchy light fog to form again overnight.

SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/

Key Points...

* Severe thunderstorms expected tomorrow afternoon NW of I-95 * Primary threat is strong damaging winds and heavy rainfall * Secondary threat is hail and even a few tornadoes * Hot and humid conditions continue with heat indicies in the mid to upper 90s.

A potent Shortwave trough and associated surface low begins to drop out of the Great Lakes on Sunday. A weaker leading shortwave associated with the warm front out ahead of the surface low will cross through the region Sunday afternoon. With deep SW flow at the surface, we should see cloud cover clear except near the South Coast and Islands. With plenty of sunshine tomorrow afternoon, temperatures will quickly rise into the 90s. With dewpoints in the low 70s tomorrow, heat indices will once again jump into the low to mid 90s across eastern MA and RI, and mid to upper 90s across western MA and CT. The heat advisory will remain in effect tomorrow for the southern CT river valley.

The heat and humidity will lead to large amounts of instability tomorrow especially with sunny conditions. HRRR mean SBCAPE around 2000J/kg and 0-6km between 30-50 knots, this will set the stage for more scattered to numerous severe thunderstorms tomorrow between 1pm-10pm NW of I-95. The primary threat will be severe wind gusts and heavy rain, with secondary threats of hail and even a few tornadoes. Breaking down each of the threats below.

Strong to damaging winds

The primary threat for severe weather tomorrow will be the strong to damaging wind gusts. An 850 mb LLJ of will be around 35-45 knots and steep low level lapse rates will already bring gusty SW winds to much of the region in the afternoon. With DCAPE values around 900J/kg the already gusty winds will be enhanced due to thunderstorms. SPC has highlighted much of western SNE in a 15% wind risk, with 30% in far NW MA for severe wind gusts.

Heavy rain and flash flooding

Precipitable water values will again be near 2.0 inches combined with tall skinny cape values and warm cloud depths approaching 10kft, storms will produce heavy rain. Storms should be moving rather quickly, but some guidance suggests the possibility for multiple rounds of convection. Given the antecedent wet conditions from all the storms the past couple days, this will elevate the flash flood risk esspically in urban centers with poor drainage.

Tornadoes

Tomorrow certainly has the greatest risk for tornadoes compared to the last couple days with a significantly more shear and better forcing. HRRR 0-3km SRH values around 300 m/s, 0-1 km SRH around 100 m/s, and STP values between 1.0-2.0 certainly indicates the possibility for tornadoes with severe thunderstorms. LCL heights under 500m in a deeply moist environment will also be favorable tornado development. Very elongated straight line hodographs in the low level could support a couple discrete splitting supercells, but confidence on this remains low. With this being said, SPC has high lighted a 5% TOR risk for much of Western MA and CT, and a 10% TOR risk in the very far NW MA.

Hail

The hail threat appears to be the most limited threat of the day with mid level lapse rates only around 5-6 C/km and a freezing level around 15kft. In order to get hail to the ground, a very strong and robust supercell will be needed esspically if there are any left splits. Given the unfavorable conditions SPC only highlights a 5% risk of hail for western MA, and CT.

Sunday night

The threat for severe thunderstorms will quickly wane between 8pm-10pm with only lingering showers and thunderstorms after 10pm. Generally should see drying conditions by day break with lows only in the upper 60s to low 70s.

LONG TERM /MONDAY THROUGH SATURDAY/

Key Points...

* Turning less humid Mon with a few diurnally driven showers * Dry & Very Warm Tue with tolerable humidity * Main risk of showers/t-storms Wed PM may linger into Thu * Dry weather returns Thu or by Fri with lower humidity

Details...

Still some uncertainty for Monday...but the latest guidance indicates initial surface trough may have already pushed deeper moisture east of the region. If this does indeed happen we would still have highs mainly in the 80s...but lowering humidity as the day progresses. The upper trough/cold pool aloft may still allow for diurnally driven showers...but if the deeper moisture is shunted east we may not have to worry about severe weather.
Too early to lock that in for sure...but that is the 12z model trend.

Mid level ridge axis crosses the region Tue allowing for dry and warm weather...but not the humidity of what we had much of this week. Highs will still be in the upper 80s to near 90 in many locations.

The humidity will again return to the region by Wednesday as the next shortwave trough approaches from the west. Many locations away from the south coast will probably see highs in the upper 80s to the lower 90s. Approaching shortwave/cold front will bring the risk for a round of showers & t-storms Wed PM. Plenty of uncertainty regarding timing/instability...but appears we may be dealing with sort of remnant EML. That will need to be watched for a severe weather risk as we get closer.

Depending on the timing...some activity may linger into Thu if the shortwave/cold front ends up on the slower side.
Otherwise...drier weather with lowering humidity by Fri.

AVIATION /02Z SUNDAY THROUGH THURSDAY/
Forecast Confidence Levels:

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

02z update...thunderstorms across NY state at 10 PM is expected to traverse SNE overnight. Storms are not expected to be severe, but frequent lightning and heavy rain will be the main issues.
Earlier discussion below.

==================================================================

Tonight...High Confidence on trends but low confidence on rain.

Daytime showers and thunderstorms should end by 00Z. Some guidance suggest elevated showers and thunderstorms are possible overnight from 04z-12z, but confidence in this is still low at this time and thus left out mention in the TAFs. IFR/LIFR conditions region wide. 30-40 knot LLJ may bring some light wind shear/turbulence towards daybreak.

Sunday...Moderate confidence on trends and rain/thunderstorms

Any overnight rain should clear by 14z the latest with rapid improvements from IFR to VFR in the afternoon. The exception to this will be the South Coast and Islands will likely remain MVFR/IFR tomorrow. Timing and coverage of thunderstorms remains uncertain tomorrow, but thinking it will be a bit latter then the previous two days starting in the west around 18z-20z, moving east through 00z-02z. Winds become gusty in the afternoon at 15-30 knots.

Sunday night...Moderate Confidence in trends. Low confidence in rain.

Back to IFR/LIFR overnight. Low chance for showers and thunderstorms, but confidence is low at this time. Winds remains gusty out of the SW at 15-25 knots

KBOS TAF... Moderate Confidence in TAF

MVFR this afternoon with periods of IFR possible. Still expecting showers with a rumble of thunder possible later this afternoon between 20z-23z. IFR tonight. Low chance for showers overnight, but confidence is low at this time. IFR improving to VFR tomorrow afternoon. Thunderstorms are possible tomorrow afternoon.

KBDL TAF...Moderate Confidence in TAF.

MVFR/VFR this afternoon with scattered thunderstorms through about 23z. MVFR/IFR overnight. Low chance for showers and thunderstorms overnight, but confidence is low at this time. VFR tomorrow with a moderate chance for thunderstorms in the afternoon, but timing remains uncertain.

Outlook /Monday through Thursday/...

Monday: Mainly VFR, with areas MVFR possible. Breezy. Slight chance SHRA.

Monday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA.

Tuesday: VFR.

Tuesday Night: VFR. Breezy.

Wednesday: Mainly VFR, with local MVFR possible. Breezy. Chance SHRA, chance TSRA.

Wednesday Night: Mainly MVFR, with areas VFR possible. Breezy.
Chance SHRA, chance TSRA.

Thursday: Mainly MVFR, with areas VFR possible. Chance SHRA.

MARINE
Forecaster Confidence Levels:

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

*** SCA in effect for Sunday ***

Saturday night...

Early evening scattered thunderstorms dissipate by late evening.
Then patchy fog reduce vsby. Light and variable winds become SW toward Sunday morning.

Sunday...

SW winds increase 15 to 25 kt, with some gusts possibly up to 35 kt at times. Low vsby in morning fog will improve during the afternoon.

Sunday Night...

Scatted showers and thunderstorms move out over the waters in the late evening. Low clouds and fog fill back in. Winds remain gusty out of the SW at 15-25 knots. Sea increase to 5-10 feet.

Outlook /Monday through Thursday/...

Monday: Winds less than 25 kt. Areas of rough seas. Slight chance of rain showers.

Monday Night: Winds less than 25 kt. Local rough seas. Slight chance of rain showers.

Tuesday: Winds less than 25 kt. Seas locally approaching 5 ft.

Tuesday Night: Winds less than 25 kt.

Wednesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Slight chance of rain showers, slight chance of thunderstorms.

Wednesday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers, isolated thunderstorms.

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

BOX WATCHES/WARNINGS/ADVISORIES
CT...Heat Advisory until 7 PM EDT Sunday for CTZ002>004.
MA...Heat Advisory until 7 PM EDT Sunday for MAZ010-011.
RI...None.
MARINE...Small Craft Advisory from noon to 8 PM EDT Sunday for ANZ230- 250-251.
Small Craft Advisory from noon Sunday to 8 AM EDT Monday for ANZ231.
Small Craft Advisory from 8 AM Sunday to 3 PM EDT Monday for ANZ232>235-237.
Small Craft Advisory from 10 AM Sunday to 9 AM EDT Monday for ANZ236.
Small Craft Advisory from 8 AM Sunday to 9 PM EDT Monday for ANZ254>256.




Weather Reporting Stations
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Stations Dist Age Wind AirWater WavesinHgDewPt
BHBM3 - 8443970 - Boston, MA 35 mi50 min 64°F 30.00


Wind History for Providence, RI
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Airport Reports
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AirportDistAgeWind ktVisSkyWeatherAirDewPtRHinHg
KFIT FITCHBURG MUNI,MA 8 sm37 mincalm4 smOvercast Mist 63°F59°F88%30.02
KASH BOIRE FIELD,NH 14 sm41 mincalm10 smOvercast61°F30.02
KBED LAURENCE G HANSCOM FLD,MA 20 sm46 minENE 034 smOvercast Mist 61°F61°F100%30.00
KAFN JAFFREY AIRPORTSILVER RANCH,NH 24 sm45 mincalm3 smOvercast Mist 61°F57°F88%30.02
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Wind History graph: FIT
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Tide / Current for Charles River Dam, Charles River, Massachusetts
   
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Charles River Dam
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Sat -- 05:07 AM EDT     Moonset
Sat -- 05:07 AM EDT     Sunrise
Sat -- 06:18 AM EDT     -0.10 feet Low Tide
Sat -- 12:33 PM EDT     9.00 feet High Tide
Sat -- 06:23 PM EDT     1.11 feet Low Tide
Sat -- 08:24 PM EDT     Sunset
Sat -- 09:40 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Charles River Dam, Charles River, Massachusetts, Tide feet
12
am
10.5
1
am
9.7
2
am
8
3
am
5.7
4
am
3.3
5
am
1.2
6
am
-0
7
am
0.2
8
am
1.7
9
am
3.6
10
am
5.7
11
am
7.6
12
pm
8.8
1
pm
8.9
2
pm
7.9
3
pm
6.2
4
pm
4.3
5
pm
2.4
6
pm
1.2
7
pm
1.4
8
pm
2.9
9
pm
5
10
pm
7.2
11
pm
9.2


Tide / Current for Charlestown Bridge, Charles River, Massachusetts
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Charlestown Bridge
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Sat -- 05:07 AM EDT     Moonset
Sat -- 05:07 AM EDT     Sunrise
Sat -- 06:16 AM EDT     -0.10 feet Low Tide
Sat -- 12:30 PM EDT     9.00 feet High Tide
Sat -- 06:21 PM EDT     1.11 feet Low Tide
Sat -- 08:24 PM EDT     Sunset
Sat -- 09:40 PM EDT     Moonrise
Tide / Current data from XTide NOT FOR NAVIGATION
Sorry tide depth graphs only, please select another station.

Charlestown Bridge, Charles River, Massachusetts, Tide feet
12
am
10.5
1
am
9.7
2
am
7.9
3
am
5.6
4
am
3.2
5
am
1.1
6
am
-0
7
am
0.3
8
am
1.7
9
am
3.6
10
am
5.8
11
am
7.7
12
pm
8.8
1
pm
8.9
2
pm
7.8
3
pm
6.2
4
pm
4.2
5
pm
2.4
6
pm
1.2
7
pm
1.4
8
pm
3
9
pm
5.1
10
pm
7.3
11
pm
9.3


Weather Map
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Boston, MA,




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