Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 230533 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 133 AM EDT Wed Jun 23 2021 .SYNOPSIS... A much drier airmass moves in place as high pressure builds in overnight. Dry weather with very comfortable humidity levels persist Wednesday and Thursday. Warmer and more humid conditions return Friday and into the weekend. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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130 AM Update... Just a few lingering showers remained near the far southeast New England coast very early this morning. Those should be departing shortly. Otherwise, much drier air was working into the region very early this morning. A mid level cloud deck still covered much of our area, but we expect skies to at least undergo partial clearing by daybreak away from the southeast New England coast. Low temps will bottom out mainly in the 50s to near 60 towards the Cape and Islands. We do expect some upper 40s across the normally coolest outlying locations of western MA. Quite a change in the airmass compared to early yesterday morning!
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... Highlights * Dry and quiet weather as high pressure builds over southern New England. Seasonable temperatures with comfortable humidity. Mid level ridge axis builds over the region through this period. At the surface high pressure will build over southern New England on Wednesday and moves offshore Wednesday night. Seasonable temperatures across the region and a much more comfortable airmass in place. Temperatures top out in the 70s across the region with dew points in the 40s. Mostly clear skies and a good radiational cooling across southern New England Wednesday night. Lows range from the mid 40s to the 50s. May need to go lower in future updates as have gone with the 25th percentile of guidance at this point in time. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Highlights... * Mild to warm afternoons and cool nights through Thursday. * Summer heat and humidity returns by this weekend with the chance for scattered showers and thunderstorms. Details... Lots of moving parts for this portion of the forecast. A low pressure is expected to pass by well to our SE Wednesday night into Thursday. HIgh pressure should then be the dominant weather feature along the Eastern Seaboard late this week into early next week. The location will be important, with the core of this high pressure south of the Maritimes. This will be close enough to result in a predominantly south to southwest flow this weekend into early next week, meaning a return to increased heat and humidity for most. Precipitation-wise, the location of this high pressure will not likely be close enough to keep us entirely dry during this time. Looking at at least a chance for mainly afternoon and evening showers and isolated thunderstorms each day Saturday through Tuesday. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
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Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Today...High Confidence. VFR with NW winds of 5 to 10 knots. Localized sea breezes will develop this afternoon along portions of the immediate coast. Tonight...High Confidence. VFR with light/calm winds. Thursday...High Confidence. VFR with SE winds of 5 to 15 knots. Low probability that some marginal MVFR ceilings approach the Cape/Nantucket towards 00z. KBOS TAF...Moderate confidence in TAF. We may have an ESE sea breeze develop from mid afternoon into early this evening. If it happens expect it to occur between 18z and 20z. KBDL TAF...High confidence in TAF. Outlook /Thursday Night through Sunday/... Thursday night and Friday: VFR. Friday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA. Saturday: Mainly VFR, with local MVFR possible. Breezy. Slight chance SHRA. Saturday Night: VFR. Breezy. Chance SHRA. Sunday: Mainly VFR, with local MVFR possible. Breezy. Slight chance SHRA.
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&& .MARINE...
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Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Tonight through Wednesday...High confidence Showers and storms coming to an end as a cold front sweeps through. Seas remain elevated to Small Craft Advisory levels with the same timing as the previous shift had indicated into Wednesday. Seas take the longest to diminish across the eastern and southern outer waters. NW winds of 10-15 kts with gusts up to 20 kts. Winds diminish to 5-10 kts and shift to the S/SW Wednesday afternoon. Wednesday night...High confidence. Light southerly to southwesterly wind as high pressure builds over the waters. Waves 2-4 ft. Outlook /Thursday Night through Sunday/... Thursday: Winds less than 25 kt. Thursday Night: Winds less than 25 kt. Slight chance of rain showers. Friday through Saturday: Winds less than 25 kt. Saturday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers. Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 2 PM EDT this afternoon for ANZ254>256. Small Craft Advisory until 11 AM EDT this morning for ANZ235- 237.
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&& $$ SYNOPSIS...Belk/BL NEAR TERM...Frank SHORT TERM...BL LONG TERM...Belk AVIATION...Frank/Belk MARINE...Belk/BL

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