Area Forecast Discussion
Issued by NWS Boston, MA

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284 FXUS61 KBOX 301755 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 155 PM EDT Thu May 30 2024 .SYNOPSIS...
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Low pressure exits this afternoon followed by improving conditions during the afternoon from west to east. Drier weather with plentiful sunshine for Friday. After a few days of temperatures at or slightly cooler than normal, the weekend into Monday offers a warming trend toward above normal temperatures and still tolerable humidity levels. Drier weather should generally prevail this weekend into at least Tuesday.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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150 PM update... Last of the comma head showers impacting NE MA will gradually end during the next few hours. Partial clearing has developed across western MA and CT and this will push eastward across rest of SNE through late afternoon as drier air moves in from the west. However, low risk for a pop-up shower in the west later this afternoon as upper level trough approaches from the west. Chilly afternoon in eastern MA with temps likely not getting out of the 50s. Highs in the 60s further west, and possibly 70 in portions of CT valley.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... Highlights: * Cooler tonight, followed by a beautiful Friday. Mid-level trough moves off shore overnight, a rouge shower not out of the question across the Cape and Island. That said, trend is drying along with with clearing skies. Noticeably cooler tonight with temperatures in the 40s to low 50s. Coolest in NW MA where the low drops into the lower 40s. Light north wind overnight, chance that the winds decouple and we are slightly cooler than forecast. With light winds and the rain from today, areas or patchy radiational fog is not out of the question. Mid-level ridging on Friday with surface high pressure will lead to a wonderful day with sunny conditions and warm temperatures in the 70s. Guidance does hint towards a seabreeze along the coast, likely keeping those communities a tad cooler.&& .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Key Points... * Temperatures will be increasing steadily each day through early next week into the 80s. * An extended stretch of mostly dry weather is expected through Wednesday but there is a chance for some scattered showers late Sunday then isolated showers each afternoon thereafter. Details... Quiet weather continues for the weekend and well into next week thanks to a broad ridge of high pressure in the mid levels and high pressure at the surface. This means mostly dry and sunny/partly sunny conditions for the weekend and even through the middle of next week. The one period to watch for the potential of some unsettled weather would be later Sunday into Monday as global guidance shows a weak shortwave dampening the ridge; however, some of the guidance shows this being suppressed too far south to impact SNE so confidence is low at this time that we`ll see any wet weather. Ensemble guidance places the odds of measurable rainfall during this period at 40-60% for western MA/CT and less further east. Either way, not expecting a washout. As for Monday through Wednesday, each day will feature the chance for a few diurnally driven showers in the afternoon, especially away from the coasts but most should stay dry. Temperature-wise we`ll kick off the weekend seasonable to slightly above seasonable for the start of June, with highs in the 70s to low 80s (CT valley). As the ridge builds in the airmass will continue to warm each day into Monday when highs will reach into the mid 80s inland and low to mid 70s along the coasts. This will continue to be the case through mid week before our next shortwave approaches bringing the chance for cooler temps and wet weather toward the end of next week. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Key Points... * Temperatures will be increasing steadily each day through early next week into the 80s. * An extended stretch of mostly dry weather is expected through Wednesday but there is a chance for some scattered showers late Sunday then isolated showers each afternoon thereafter. Details... Quiet weather continues for the weekend and well into next week thanks to a broad ridge of high pressure in the mid levels and high pressure at the surface. This means mostly dry and sunny/partly sunny conditions for the weekend and even through the middle of next week. The one period to watch for the potential of some unsettled weather would be later Sunday into Monday as global guidance shows a weak shortwave dampening the ridge; however, some of the guidance shows this being suppressed too far south to impact SNE so confidence is low at this time that we`ll see any wet weather. Ensemble guidance places the odds of measurable rainfall during this period at 40-60% for western MA/CT and less further east. Either way, not expecting a washout. As for Monday through Wednesday, each day will feature the chance for a few diurnally driven showers in the afternoon, especially away from the coasts but most should stay dry. Temperature-wise we`ll kick off the weekend seasonable to slightly above seasonable for the start of June, with highs in the 70s to low 80s (CT valley). As the ridge builds in the airmass will continue to warm each day into Monday when highs will reach into the mid 80s inland and low to mid 70s along the coasts. This will continue to be the case through mid week before our next shortwave approaches bringing the chance for cooler temps and wet weather toward the end of next week. && .AVIATION /18Z THURSDAY THROUGH MONDAY/...
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Forecast Confidence Levels: Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through 00z... Areas of MVFR cigs with IFR Cape/Islands will gradually improve to VFR through the afternoon. Showers across NE MA will end by 20z. N wind gusts to 20-25 kt over Cape/Islands. Tonight... High confidence. Areas of MVFR outer Cape/Islands early, otherwise VFR. Light N winds. Friday and Friday night... High confidence. VFR. NW 5-10 kt Fri but sea-breezes developing along the immediate coast. Light wind Fri night. KBOS TAF... High confidence. Brief MVFR cigs until 19-20z, otherwise VFR. Sea-breeze develops around 15z Fri. KBDL TAF... High confidence. Outlook /Friday Night through Monday/... VFR.
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&& .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Today through Friday... Weak surface low pressure system brings widespread rain, at times heavy this morning into early afternoon, a few lingering showers are possible this evening, although the trend is to dry things out. A period of gusty NNE wind this afternoon 20 to 24 knots and building seas to 3-5 ft along the eastern outer waters. Have opt for a SCA for the outer eastern waters this afternoon into early evening for marginal seas. Dry with light northwest winds on Friday morning, wind becomes southwest later in the day less than 15 knots. Seas 3 ft or less. Outlook /Friday Night through Monday/... Winds less than 25 kt. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ231- 232-254-255. Small Craft Advisory until 8 PM EDT this evening for ANZ250. Small Craft Advisory until 4 PM EDT this afternoon for ANZ251.
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&& $$ SYNOPSIS...BW/Dooley NEAR TERM...KJC SHORT TERM...Dooley LONG TERM...BW AVIATION...BW/Dooley MARINE...KJC/BW