Marine Weather and Tide Forecast for Siasconset, MA
 | Sunrise 5:27 AM Sunset 7:56 PM Moonrise 8:07 PM Moonset 5:03 AM |
ANZ094
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ANZ005 508 Pm Edt Mon May 12 2025
Synopsis for eastport me to stonington me out 25 nm - High pres crosses the region tonight, then moves se of the region Tue into Wed. Another low pres slowly approaches from the W into late week as an occluded front moves through Fri night. A storm system crosses over the area on Sat night.
7 Day Forecast for Marine Location Near Siasconset, MA
NEW! Add second zone forecast
FXUS61 KBOX 122333 AFDBOX
Area Forecast Discussion National Weather Service Boston/Norton MA 733 PM EDT Mon May 12 2025
SYNOPSIS
A weak backdoor cold front will drop south through New England late tonight as high pressure remains over the Maritimes through Wednesday. Low pressure over the Carolinas Wednesday will weaken as it approaches the Northeast Thursday and Friday, then a cold front should cross the region Saturday.
NEAR TERM /THROUGH TUESDAY/
Updated 130 PM Mon
Key Message:
* Continued dry but cooler near coast Tue.
Our area remains under influence of NW-SE oriented ridge from Great Lakes to Mid Atlantic with one upper low over Maritimes and another across southeastern states. This pattern stays locked in through Tue but a weak backdoor front will drop south through New England, either dissipating or pushing south of New England Tue morning. Its only effect will be a wind shift to NE, and with high pressure remaining offshore and a weak gradient, onshore flow Tue will bring cooler temps to locations near coast while interior areas have another day of above normal temps.
SHORT TERM /TUESDAY NIGHT/
Updated 130 PM Mon
Key Message:
* Few showers possible late Tue night in western MA/CT.
Ridge axis slowly shifts into northern New England as upper low over Maritimes exits region. This will also allow the other closed low over Carolinas to begin to eject northward, but plenty of dry air should remain over SNE to limit northward extent of any showers. It's possible we see a few showers sneak into western parts of MA/CT late Tue night but that could end up just being a few sprinkles or brief showers from a mid level cloud deck.
LONG TERM /WEDNESDAY THROUGH MONDAY/
Updated 130 PM Mon
Key Messages:
* Pattern turns warmer/more humid into weekend.
* Best chances for showers/storms Fri and Sat.
Seeing good agreement among longer range guidance which gives us higher confidence in overall pattern. Weakening upper low from the south opens up over Northeast later this week as it runs up into upper ridging that shifts into Maritimes, and is eventually kicked out by a stronger northern stream closed low which tracks across southern Canada.
Increasing southerly flow aloft will result in at least a few showers in Wed-Thu timeframe. We should see more instability and stronger dynamics ahead of cold front in Fri-Sat timeframe when showers/storms should be more numerous. CSU ML guidance also shows a low risk of severe storms both days but pattern doesn't look to favorable here in SNE and higher odds are certainly farther W and SW of our region - something to monitor in coming days. Later in weekend, broad upper trough remains in place which should bring at least diurnal clouds if not a few showers, and onshore flow should also bring cooler temperatures (closer to average for mid May).
AVIATION /00Z TUESDAY THROUGH SATURDAY/
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00Z TAFs: High confidence.
VFR. SW winds gust to 20-25kt before diminishing this evening between 00z-002z and shifting to N/NW overnight. E/NE winds 10-15kt Tue diminishing to 10kt or less Tue night.
KBOS TAF...High Confidence in TAF.
KBDL TAF...High Confidence in TAF.
Outlook /Wednesday through Saturday/...
Wednesday: Mainly VFR, with local MVFR possible. Slight chance SHRA.
Wednesday Night: MVFR/IFR conditions possible. Chance SHRA.
Thursday: Mainly VFR, with areas IFR possible. Chance SHRA, isolated TSRA.
Thursday Night: Mainly VFR, with areas IFR possible. Slight chance SHRA.
Friday: Mainly VFR, with local IFR possible. Chance SHRA, isolated TSRA.
MARINE
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Updated 130 PM Mon
Overall high confidence through late in the week.
Decided to hoist SCAs for Boston Harbor and most of E MA waters for 25kt gusts through early this evening based upon seeing deeper mixing aloft on forecast soundings. Probably marginal for most but confidence is higher around Cape Cod and Islands, especially near shore.
Weak backdoor front drops south later tonight which shifts winds to N/NW, then onshore winds (mainly E/NE) expected Tue and Tue night but winds and seas stay well below SCA.
Later in week, low pressure over Carolinas weakens as it approaches Northeast Thu-Fri.
Outlook /Wednesday through Saturday/...
Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers.
Wednesday Night through Thursday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers, isolated thunderstorms.
Thursday Night: Winds less than 25 kt. Areas of seas approaching 5 ft.
Friday: Winds less than 25 kt. Seas locally approaching 5 ft.
Slight chance of rain showers.
BOX WATCHES/WARNINGS/ADVISORIES
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ230.
Small Craft Advisory until 9 PM EDT this evening for ANZ231>234-250-254-255.
Area Forecast Discussion National Weather Service Boston/Norton MA 733 PM EDT Mon May 12 2025
SYNOPSIS
A weak backdoor cold front will drop south through New England late tonight as high pressure remains over the Maritimes through Wednesday. Low pressure over the Carolinas Wednesday will weaken as it approaches the Northeast Thursday and Friday, then a cold front should cross the region Saturday.
NEAR TERM /THROUGH TUESDAY/
Updated 130 PM Mon
Key Message:
* Continued dry but cooler near coast Tue.
Our area remains under influence of NW-SE oriented ridge from Great Lakes to Mid Atlantic with one upper low over Maritimes and another across southeastern states. This pattern stays locked in through Tue but a weak backdoor front will drop south through New England, either dissipating or pushing south of New England Tue morning. Its only effect will be a wind shift to NE, and with high pressure remaining offshore and a weak gradient, onshore flow Tue will bring cooler temps to locations near coast while interior areas have another day of above normal temps.
SHORT TERM /TUESDAY NIGHT/
Updated 130 PM Mon
Key Message:
* Few showers possible late Tue night in western MA/CT.
Ridge axis slowly shifts into northern New England as upper low over Maritimes exits region. This will also allow the other closed low over Carolinas to begin to eject northward, but plenty of dry air should remain over SNE to limit northward extent of any showers. It's possible we see a few showers sneak into western parts of MA/CT late Tue night but that could end up just being a few sprinkles or brief showers from a mid level cloud deck.
LONG TERM /WEDNESDAY THROUGH MONDAY/
Updated 130 PM Mon
Key Messages:
* Pattern turns warmer/more humid into weekend.
* Best chances for showers/storms Fri and Sat.
Seeing good agreement among longer range guidance which gives us higher confidence in overall pattern. Weakening upper low from the south opens up over Northeast later this week as it runs up into upper ridging that shifts into Maritimes, and is eventually kicked out by a stronger northern stream closed low which tracks across southern Canada.
Increasing southerly flow aloft will result in at least a few showers in Wed-Thu timeframe. We should see more instability and stronger dynamics ahead of cold front in Fri-Sat timeframe when showers/storms should be more numerous. CSU ML guidance also shows a low risk of severe storms both days but pattern doesn't look to favorable here in SNE and higher odds are certainly farther W and SW of our region - something to monitor in coming days. Later in weekend, broad upper trough remains in place which should bring at least diurnal clouds if not a few showers, and onshore flow should also bring cooler temperatures (closer to average for mid May).
AVIATION /00Z TUESDAY THROUGH SATURDAY/
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00Z TAFs: High confidence.
VFR. SW winds gust to 20-25kt before diminishing this evening between 00z-002z and shifting to N/NW overnight. E/NE winds 10-15kt Tue diminishing to 10kt or less Tue night.
KBOS TAF...High Confidence in TAF.
KBDL TAF...High Confidence in TAF.
Outlook /Wednesday through Saturday/...
Wednesday: Mainly VFR, with local MVFR possible. Slight chance SHRA.
Wednesday Night: MVFR/IFR conditions possible. Chance SHRA.
Thursday: Mainly VFR, with areas IFR possible. Chance SHRA, isolated TSRA.
Thursday Night: Mainly VFR, with areas IFR possible. Slight chance SHRA.
Friday: Mainly VFR, with local IFR possible. Chance SHRA, isolated TSRA.
MARINE
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Updated 130 PM Mon
Overall high confidence through late in the week.
Decided to hoist SCAs for Boston Harbor and most of E MA waters for 25kt gusts through early this evening based upon seeing deeper mixing aloft on forecast soundings. Probably marginal for most but confidence is higher around Cape Cod and Islands, especially near shore.
Weak backdoor front drops south later tonight which shifts winds to N/NW, then onshore winds (mainly E/NE) expected Tue and Tue night but winds and seas stay well below SCA.
Later in week, low pressure over Carolinas weakens as it approaches Northeast Thu-Fri.
Outlook /Wednesday through Saturday/...
Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers.
Wednesday Night through Thursday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers, isolated thunderstorms.
Thursday Night: Winds less than 25 kt. Areas of seas approaching 5 ft.
Friday: Winds less than 25 kt. Seas locally approaching 5 ft.
Slight chance of rain showers.
BOX WATCHES/WARNINGS/ADVISORIES
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ230.
Small Craft Advisory until 9 PM EDT this evening for ANZ231>234-250-254-255.
Link to 1 hour of 5 minute data for KACK
Terminal Aerodrome Forecast (TAF) for KACK
Wind History Graph: ACK
(wind in knots)
GEOS Local Image of Northeast
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