Sunrise 5:33 AM   Sunset 7:49 PM Moonrise 3:48 AM   Moonset 3:46 PM

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ANZ230 Boston Harbor- 405 Pm Edt Sat May 4 2024
Tonight - E winds 5 to 10 kt. Waves around 2 ft this evening, then 1 foot or less. Sun - SE winds 5 to 10 kt. Gusts up to 20 kt in the afternoon. Waves around 2 ft. A chance of showers in the afternoon. Sun night - S winds 5 to 10 kt. Waves around 2 ft. Patchy fog. Showers. Vsby 1 to 3 nm. Mon - SW winds 5 to 10 kt, increasing to 10 to 15 kt in the afternoon. Waves 1 foot or less. A chance of showers. Patchy fog in the morning with vsby 1 to 3 nm. Mon night - SW winds 5 to 10 kt, becoming nw after midnight. Waves 1 foot or less. Tue - N winds 5 to 10 kt, becoming se 10 to 15 kt in the afternoon. Waves 1 foot or less. Tue night - S winds 5 to 10 kt, becoming N after midnight. Waves 1 foot or less. A chance of showers after midnight. Wed - E winds 5 to 10 kt with gusts up to 20 kt. Waves around 2 ft. Showers likely. Wed night through Thu night - NE winds around 10 kt. Waves 2 to 3 ft. Showers likely.
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 405 Pm Edt Sat May 4 2024
Synopsis for massachusetts and rhode island coastal waters - High pressure begins to move east tonight, but dry weather remains through Sunday morning. Weak low pressure system and cold front brings rain Sunday afternoon through Monday morning. Dry weather returns Monday evening through Tuesday. Low chance for showers mid to late next week as several disturbances pass over the waters.

FXUS61 KBOX 041931 AFDBOX

Area Forecast Discussion National Weather Service Boston/Norton MA 331 PM EDT Sat May 4 2024

SYNOPSIS

Cloudy and cool weather is on tap through Sunday with a period of widespread showers arriving from the west...mainly later Sunday into Sunday night. Mild and dry to start the work week before cooler and unsettled conditions Wednesday through next weekend

NEAR TERM /UNTIL 6 AM SUNDAY MORNING/

330 PM Update...

* Clouds continue to overspread the region off the ocean tonight * Overnight low temps mainly in the 40s

The upper level ridge axis will be shifting east of the region. This coupled with high pressure in the vicinity of the Canadian Maritimes will result onshore flow
As the boundary layer cools
expect low clouds to continue to develop and expand westward tonight. Dry weather will prevail tonight...but we may see a few spot showers develop near daybreak west of the CT River Valley. Overnight low temps will bottom out mainly in the 40s.

SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/

Key Points...

* Cloudy/cool Sun with showers arriving across the interior * A period of widespread showers Sun night across the entire region

Details...

Sunday and Sunday night...

High pressure will shift east of the Canadian Maritimes as shortwave energy approaches from the west on Sunday. Onshore flow low level flow will result in cloudy skies persisting and cool temperatures too. Highs will only be in the 50s even across the distant interior.

While a few warm advection spot showers are possible across the interior during the morning...the stronger forcing/deeper moisture does not arrive until the afternoon. So thinking the main threat for showers will be be Sunday afternoon across interior MA & CT...but should wait until late Sunday afternoon/evening across the coastal plain. Enough forcing exists for a period of widespread showers Sunday night. Modest forcing and Pwats 1-2 standard deviations above normal could result in a brief downpour or two. While we can not rule out a rumble or two of thunder with some marginal elevated instability...thinking it was not worth inserting into the forecast at this point. Low temperatures Sunday night will mainly be in the middle to upper 40s.

LONG TERM /MONDAY THROUGH SATURDAY/

* Generally dry with above normal temperatures Monday and Tuesday

* Persistent period of cool temps and heightened rain chances Wednesday through early next week.

Tale of two patterns for the upcoming work week with strong upper level ridging in place through Tuesday before a trough develops for the second half of the week.

Some residual showers may linger into Monday morning, primarily across far southeastern MA and the Cape. Weak frontal passage may initiate some shower activity come Monday evening but with drying flow aloft, questions remain on the geographic spread of this second round of showers. All in all, Monday looks to shape up as a primarily dry day, with above normal temperatures as boundary layer temperatures warm to around 15C. As noted by the previous forecaster, ensemble probabilities of 70F+ temps remain high, between 80-100%, across the interior. Tuesday continues to look like the pick of the week as temperatures soar well into the 70s.
Downsloping northwest flow that develops after the lunch hour and abundant sunshine should allow for a few localities in the CT River Valley to make a run at 80F. While ensemble probabilities remain low regarding temps hitting the 80F mark, conditions appear to be a recipe for an overachieving type day. For both Monday and Tuesday, weak pressure gradient will allow for seabreeze development, so while it may sound like a broken record, temps along the coastline will be significantly cooler.

Ridge breaks down as trough develops over the eastern CONUS Wednesday- Friday. CMC, GEFS, and ECMWF remain at odds regarding how potent the trough will be, but a series of shortwaves and persistent low pressure located over the Great Lakes and a stalled frontal boundary will bring rounds of showers to southern New England Wednesday through the weekend. Ensemble probs aren't particularly remarkable when it comes to QPF, with just 20-50% probs of 0.5" QPF over any 24 hour period, but onshore flow will make for a prolonged period of stratus and shower chances with temperatures locked in the upper 50s and low 60s.

AVIATION /20Z SATURDAY THROUGH THURSDAY/

Forecast Confidence Levels:

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

18z TAF Update...

This afternoon and tonight...High Confidence in trends, but more uncertainty in regards to specific timing.

MVFR ceilings along the coast this afternoon will gradually spread westward tonight...eventually covering the entire region.
We also expect some IFR conditions to develop overnight with even localized LIFR cigs/vsbys in the high terrain. Light E winds.

Sunday...Moderate Confidence.

IFR/MVFR ceilings will trend to mainly MVFR thresholds with some diurnal heating despite the cloudy skies. Some showers will work into mainly interior MA & CT during the afternoon hours, but will not reach the coastal plain until late Sunday afternoon/evening. SE winds 5 to 10 knots.

Sunday night...Moderate Confidence.

Conditions should lower to mainly IFR with localized LIFR cigs/vsbys given the cooling boundary layer Sunday night.
A round of widespread showers will overspread the region from west to east Sunday night too. SE winds shift to more of a S direction at 5 to 10 knots.

KBOS TAF...High confidence in trends but more uncertainty in regards to specific timing.

KBDL TAF...High confidence in trends but more uncertainty in regards to specific timing.

Outlook /Monday through Thursday/...

Monday: Mainly VFR, with local IFR possible. Chance SHRA.

Monday Night through Tuesday: VFR. Slight chance SHRA.

Tuesday Night: VFR. Chance SHRA.

Wednesday: Mainly VFR, with areas MVFR possible. Chance SHRA, isolated TSRA.

Wednesday Night: MVFR/IFR conditions possible. Chance SHRA.

Thursday: Mainly VFR, with local IFR possible. Chance SHRA.

MARINE

Forecaster Confidence Levels:

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

Tonight through Sunday night...High Confidence.

High pressure in the vicinity of the Canadian Maritimes tonight will shift east of there on Sunday. This as a shortwave energy approaches from the west late Sunday and Sunday night
That being said
the pressure gradient remains rather weak so winds/seas will remain below small craft advisory thresholds through Sunday night. E winds 5 to 15 knots tonight shift to the SE Sunday and then more to the S on Sunday night.

Outlook /Monday through Thursday/...

Monday: Winds less than 25 kt. Seas locally approaching 5 ft.
Chance of rain showers. Local visibility 1 nm or less.

Monday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers.

Tuesday: Winds less than 25 kt. Slight chance of rain showers.

Tuesday Night through Thursday: Winds less than 25 kt. Chance of rain showers.

BOX WATCHES/WARNINGS/ADVISORIES
CT...None.
MA...None.
RI...None.
MARINE...None.

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Neponset
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Sat -- 02:16 AM EDT     0.59 feet Low Tide
Sat -- 03:47 AM EDT     Moonrise
Sat -- 05:34 AM EDT     Sunrise
Sat -- 08:23 AM EDT     10.16 feet High Tide
Sat -- 02:46 PM EDT     -0.07 feet Low Tide
Sat -- 03:45 PM EDT     Moonset
Sat -- 07:47 PM EDT     Sunset
Sat -- 08:57 PM EDT     10.41 feet High Tide
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Neponset, Neponset River, Massachusetts, Tide feet

Boston Harbor
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Sat -- 02:16 AM EDT     0.00 knots Slack
Sat -- 03:46 AM EDT     Moonrise
Sat -- 05:09 AM EDT     1.10 knots Max Flood
Sat -- 05:34 AM EDT     Sunrise
Sat -- 08:02 AM EDT     -0.00 knots Slack
Sat -- 12:11 PM EDT     -1.17 knots Max Ebb
Sat -- 02:42 PM EDT     0.00 knots Slack
Sat -- 03:44 PM EDT     Moonset
Sat -- 05:48 PM EDT     1.23 knots Max Flood
Sat -- 07:47 PM EDT     Sunset
Sat -- 08:39 PM EDT     -0.00 knots Slack
Tide / Current data from XTide NOT FOR NAVIGATION

Boston Harbor, Massachusetts Current, knots

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