800 FXUS61 KBOX 090634 AFDBOXArea Forecast Discussion National Weather Service Boston/Norton MA 234 AM EDT Tue Sep 9 2025
.SYNOPSIS...
Dry weather prevails most of this week and weekend as high pressure remains over New England. Seasonable to slightly cooler than normal temperatures can be expected. A coastal low pressure system brings a some rain showers Wednesday; best chance is on Cape Cod and the Islands but can`t rule out some showers further inland.
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.NEAR TERM /THROUGH TONIGHT/...
Key Messages...
* Sunny to start with increasing clouds in the afternoon and evening from the southeast.
* Highs in the low to mid 70s; lows in the low 60s on the Cape and islands while interior high terrain locations may drop into the 40s!
* Breezy, especially in southeast MA.
A quiet and cooler than average day is on tap for today under the influence of a sprawling high pressure over Nova Scotia. This, combined with an approaching coastal low well to our south will direct increasingly breezy cool northeast wind over southern New England keeping highs in the low 70s east, mid 70s in the typically warmer CT Valley. Winds will gust 20-25 mph over the Cape and islands, less so further to the north and west. A Small Craft Advisory will be in effect for the southern outer waters. Tonight said coastal low will move a bit closer bringing a plum of moisture out ahead of it. Thus, expecting low clouds to encroach on the southeast coast, expanding to the north and west through the night. There is potential for some drizzle or light rain as early as Tuesday night, but sounding indicate a decent amount of dry air to overcome, so more likely that it is limited to low stratus clouds until Wednesday. The exact timing of these incoming clouds will have a big impact on low temperatures as they cut off radiational cooling; currently looking like we should still be able to radiate early in northwest SNE, down into the upper 40s/low 50s while areas on Cape Cod may only drop to the low 60s.
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.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
Key Messages...
* Rain showers possible Wednesday and Wednesday night; best chance over the south coast but may expand into northern CT/RI/eastern MA.
* Cooler, in the upper 60s for most.
Wednesday the coastal low moves off the North Carolina coast and passes offshore, southeast of the 70/40 benchmark. This will limit its impact on the region to thickening cloudcover for most, though rain showers are possible generally south of the MA/CT border; best odds are the immediate southeast coast with lessening rain chances to the north and west. EPS ensemble has increased the odds of >0.1" of rain on Wednesday in the last 24 hours though it remains the most bullish; POPs have been increased/expanded north slightly into much of CT.
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.LONG TERM /THURSDAY THROUGH MONDAY/...
Key Messages...
* Mostly dry.
* Seasonable temperatures with the warmest day being Thursday.
Thursday low pressure pulls away leaving a building high pressure in its place. This high will drive weather through the weekend leading to dry and seasonable weather. The warmest day will be Thursday as highs push into the upper 70s/low 80s. This is ahead of a mid level cold front that sinks south behind the exiting system dropping 925 mb temps from +18C to +12C; expect high temperatures back in the low 70s through the rest of the forecast with lows in the 40s and 50s.
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.AVIATION /07Z TUESDAY THROUGH SATURDAY/... Forecaster Confidence Levels...
Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.
06z TAF Update: No changes.
Today: High confidence.
VFR; high clouds for central and eastern airports. NE winds increase to around 5-10 kt for interior Southern New England, and around 10-15 kt with gusts up to 20 kt for eastern MA, RI, and the Cape and Islands airports.
Tonight: High confidence in trends, but moderate on timing and norhtwestward coverage of stratus.
VFR for most of western New England, though it`s possible that coastal stratus may expand into central and eastern terminals as the night progresses. Low chance at a rain shower or drizzle underneath the stratus. NE winds continue around 5-10 kt interior airports, and around 10-15 kt with gusts to 20 kt.
Wednesday: Moderate Confidence.
VFR for far northwest terminals, MVFR to IFR for terminals central and eastern terminals where low stratus and -RA are likely through much of the day. NE winds 10-15 kts with gusts to 20 kts.
KBOS Terminal...High confidence.
KBDL Terminal...High confidence.
Outlook /Thursday through Saturday/...
Thursday through Friday: VFR. Breezy.
Friday Night through Saturday: VFR.
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.MARINE... Forecaster Confidence Levels...
Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent.
Small craft advisories are in effect today through Wednesday for the far southern waters, as seas build to around 4-6 ft. NE winds will be increasing today with winds 15-20 kt and gusts 25 kt, and around 10-15 kt over the northeast waters. These conditions should remain steady through tonight as well. Low chance at patchy drizzle or a light rain shower, with better chances over the southeast outer waters. Rain showers increase in coverage on Wednesday.
Outlook /Thursday through Saturday/...
Thursday through Thursday Night: Winds less than 25 kt. Areas of seas approaching 5 ft.
Friday: Winds less than 25 kt. Seas up to 5 ft.
Friday Night: Winds less than 25 kt. Seas locally approaching 5 ft.
Saturday: Winds less than 25 kt.
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.BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 2 PM this afternoon to 8 PM EDT Wednesday for ANZ254. Small Craft Advisory from 8 AM this morning to 8 PM EDT Wednesday for ANZ255-256.
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SYNOPSIS...BW NEAR TERM...BW SHORT TERM...BW LONG TERM...BW AVIATION...BW MARINE...BW
NWS BOX Office Area Forecast Discussion