Sunrise 5:35 AM   Sunset 7:52 PM Moonrise 3:50 AM   Moonset 3:48 PM

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ANZ230 Boston Harbor- 1004 Am Edt Sat May 4 2024
This afternoon - E winds around 10 kt. Waves 1 foot or less. Tonight - E winds 5 to 10 kt. Waves 1 foot or less. Sun - SE winds 5 to 10 kt. Waves 1 foot or less. A chance of rain in the afternoon. Sun night - S winds 10 to 15 kt. Gusts up to 20 kt in the evening. Waves around 2 ft. Patchy fog. Showers. Vsby 1 to 3 nm after midnight. Mon - SW winds around 10 kt. Waves 1 foot or less. Showers likely, mainly in the morning. Patchy fog in the morning with vsby 1 nm or less. Mon night - SW winds around 10 kt, becoming nw after midnight. Waves 1 foot or less. Tue and Tue night - NE winds 5 to 10 kt, becoming s. Waves 1 foot or less. Wed and Wed night - SE winds 5 to 10 kt. Waves around 2 ft. 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.

ANZ200 1004 Am Edt Sat May 4 2024
Synopsis for massachusetts and rhode island coastal waters - High pressure remains anchored over new england and the nearby coastal waters through Sunday. A weak cold front then moves across new england Monday and offshore Monday night. Weak high pressure builds back over the area Tuesday. A series of weak lows then pass over or just south of new england mid to late next week.

FXUS61 KBOX 041629 AFDBOX

Area Forecast Discussion National Weather Service Boston/Norton MA 1229 PM EDT Sat May 4 2024

SYNOPSIS

High pressure off the Canadian Maritimes will continue to bring dry weather with cool temperatures along the coast. A slow- moving frontal boundary brings widespread showers Sunday into early Monday. Then gradual clearing Monday afternoon along with warming temperatures. Tuesday looks to be the pick of the week, with abundant sunshine and highs in the 70s to near 80, although significantly cooler near the coast with afternoon seabreezes.
Then lots of clouds Wed, Thu and Fri along with periodic showers possible.

NEAR TERM /UNTIL 6 PM THIS EVENING/

9 AM Update

* Partly Sunny with some increasing clouds into the afternoon * Highs lower 50s coast, 60+ inland and near 70 lower CT Rvr

Previous forecast is on track. High pressure across the Canadian Maritimes will continue to generate a low level easterly flow of air across southern New England
Therefore
we will have a large range in temperatures across the region. Highs should range from the lower 50s along the immediate coast...but 60+ not too far inland and near 70 in the lower CT River Valley.

Dry weather with partly sunny skies are anticipated through the afternoon with upper level ridging in control. We do expect some lower clouds to invade areas near the coast and some higher clouds to overspread the region from the west through the afternoon.

SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/

Tonight

Overcast skies fill back in overnight as the boundary layer cools.
This will limit temperatures from falling to far, so expect seasonable low temps in the low to mid 40s across much of the region. High pressure drops to the southeast which will result in easterly winds gradually shifting to the southeast as we approach the dawn hours.

Tomorrow

Winds shift from southeast to south during the day tomorrow allowing for a surge of moisture across the region. This will support increasing moisture with PWATs rising close to an inch across the region. Precip chances increase gradually from west to east across the region as northern stream short wave energy traverses over The Northeast. Latest suite of model guidance suggests shower chances will peak during the mid-afternoon hours with the steadiest precipitation taking place tomorrow night (see long-term AFD). Skies will be overcast for much of the day tomorrow which will support cooler temperature sin the mid to upper 50s across the region.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/

Highlights:

* Cool with rain Sunday into early Mon, then gradual clearing Monday afternoon, although clouds may linger over southeast MA

* Tue looks to be the pick of the week, with abundant sunshine and highs in the 70s to near 80, although much cooler at the coast

* Lots of clouds Wed, Thu & Fri along with the risk of periodic showers and cooler

Temperatures...

Warm westerly flow aloft Monday with 850 mb temps well above normal, about +11C at 18z. Timing of clearing will be crucial to temp forecast. Ensembles supporting 80-100% probability of 70+ highs Monday in the CT River Valley and Merrimack River Valley. More uncertainty southeast across RI and southeast MA given departure timing of clouds. Not quite as warm aloft Tue, but still above normal with +8C to +9C at 850 mb, but warmer blyr temps of +16 to +17C at 925 mb, along with NW winds providing downslope flow. This results in ensembles offering 90-100% probabilities of 70+ highs away from the coastline, where afternoon seabreezes will yield cooler temps. Farther inland, not out of the question a few towns make a run at 80 degs! This combined with abundant sunshine, low dew pts/low RH likely results in Tue being the pick of the week.

Not as warm Wed, Thu and Fri with frontal boundary getting hung up over or near SNE, along with possible waves of low pressure tracking south of the region. Highs likely in the 60s, except 50s along the coast, including Cape Cod and the Islands.

Precipitation...

Height falls and associated cold front will combine with good moisture advection (PWATs +2 sigma) to yield widespread showers Sunday afternoon thru Monday morning across southeast MA. High probability for 0.10 to 0.25 inches of rainfall during this time, with low probs up to 0.50 inches. Clearing develops NW to SE during Monday afternoon (last across SE MA) as the dry slot overspreads the region. With diurnal heating, weak cyclonic flow aloft and surface front lingering over the region, low probability of a few showers and/or an isolated thunderstorm late in the day across the interior, where duration of heating/sunshine will be greatest.

Dry weather Tuesday with PWATs only about 60% of normal. Then becoming unsettled Wed, Thu and possibly Fri, along with a low confidence forecast. Negative height anomaly downstream over Newfoundland keeps a ridge axis with above normal heights from the Mid Atlantic into New England. Meanwhile, a positive tilt trough over the high plains ejects multiple plumes of moisture towards New England. Models struggling with the large scale flow, specifically how much of this moisture advects east into SNE, or dampens out running into the ridge or is shunted southeast of New England? Nonetheless, chance of showers both Wed, Thu and Fri. Although, there will also be periods of dry weather during this time period.

AVIATION /16Z SATURDAY THROUGH WEDNESDAY/
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 mid to late afternoon hours. 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 Wednesday/...

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. Breezy. Chance SHRA, isolated TSRA.

MARINE
Forecaster Confidence Levels:

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

Marine

Today through Tomorrow

Conditions remain on the calm and quiet side across the coastal waters through the weekend with high pressure largely in control.
Easterly winds today become more southeasterly overnight and eventually southerly by Sunday. Seas generally in the 1 to 3 foot range.

Outlook /Sunday Night through Wednesday/...

Sunday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Rain showers likely.

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

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 Wednesday: 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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Charlestown Bridge
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Sat -- 02:17 AM EDT     0.59 feet Low Tide
Sat -- 03:47 AM EDT     Moonrise
Sat -- 05:34 AM EDT     Sunrise
Sat -- 08:29 AM EDT     10.16 feet High Tide
Sat -- 02:47 PM EDT     -0.07 feet Low Tide
Sat -- 03:45 PM EDT     Moonset
Sat -- 07:47 PM EDT     Sunset
Sat -- 09:03 PM EDT     10.41 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Charlestown Bridge, Charles River, Massachusetts, Tide feet

Charles River Dam
Click for Map
Sat -- 02:19 AM EDT     0.59 feet Low Tide
Sat -- 03:47 AM EDT     Moonrise
Sat -- 05:34 AM EDT     Sunrise
Sat -- 08:32 AM EDT     10.16 feet High Tide
Sat -- 02:49 PM EDT     -0.07 feet Low Tide
Sat -- 03:45 PM EDT     Moonset
Sat -- 07:47 PM EDT     Sunset
Sat -- 09:06 PM EDT     10.41 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Charles River Dam, Charles River, Massachusetts, Tide feet

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