Area Forecast Discussion
Issued by NWS Boston, MA

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419 FXUS61 KBOX 291822 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 222 PM EDT MON AUG 29 2016 .SYNOPSIS... A cold front exits southern New England this afternoon, which may be accompanied by a spot shower or thunderstorm. Weak high pressure brings dry weather Tuesday. Warm and humid weather returns Wednesday ahead of another cold front, which will bring scattered showers and a few thunderstorms Wednesday night, lingering along the south coast on Thursday. Large high pressure will build out of central Canada, bringing dry, seasonable conditions into the upcoming holiday weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1PM update... No major changes except to increase temps for the afternoon. Good mixing has already allowed a few near 90s. Previous Discussion... Low risk of an isolated shower this morning. Most places will remain dry as instability remains limited and west-southwest winds yield weak convergence. Mid level dry air and associated subsidence rush in from the northwest to southeast, yielding dry and partly sunny conditions this afternoon. Warm, with highs in the mid to upper 80s...perhaps briefly touching 90 in a few spots. However, developing west-northwest winds 10-20 mph behind this front will yield lower humidity this afternoon. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... Weak high pressure arrives tonight and Tuesday. This will mean dry weather with lower humidity. Relatively light winds will also mean good radiational cooling tonight, and likely seabreezes Tuesday. Near to slightly above normal temperatures expected. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Highlights... * Cold front will bring the chance for showers and a few thunderstorms Wednesday night and Thursday * Dry, seasonable conditions move in Friday into the holiday weekend Overview... Models remain consistent for the most part in bringing a cold front across the region, though will tend to slow down to due to tropical activity off the eastern seaboard in the form of Tropical Depression 8 off the Carolina coast early this morning. The front will also slow as it crosses while what is left of the depression passes offshore. Looks like the front should offshore during Thursday at this point. Very good run to run model consistency continues with the large Canadian high pressure that builds slowly SE across the Great Lakes into the northeast late this week into the holiday weekend. Will see cool temperatures Friday morning, upwards to 5 degrees below seasonal normals for early September across NW Mass, then will gradually moderate over the weekend. Looking like a fine holiday weekend weatherwise so far. Details... Tuesday night...Moderate to high confidence. Weak high pressure moves offshore. Winds shift to light S-SW or become calm. With temperatures falling back close to or at the dewpoints across the region, mainly in the upper 50s to mid 60s, there will be patchy fog developing mainly after midnight through sunrise. Wednesday...Moderate confidence. Models have trended a bit slower with the arrival of the leading showers/thunderstorms ahead of an approaching cold front out of NY state, thanks to Tropical Depression 8 off the mid Atlantic coast holding the ridging into the region a bit longer. So, will see dry conditions for most areas, but can not rule out a few showers reaching into NW Mass late Wed afternoon. Dewpts will be slowly increasing with the SW winds in place, so it will feel more summer like. Expect highs mainly in the lower-mid 80s, though some upper 70s will linger across the E slopes of the Berkshires as well as outer Cape Cod and the islands. Wednesday night through Thursday night...Moderate confidence. Bulk of precip moves across the region during this timeframe as the cold front slowly pushes through. Some question on timing due to the movement of TD 8 south of the region, which will tend to slow the progression of the front offshore. Best chance for showers/isolated thunderstorms will continue across central and northern areas, but a few showers could linger through Thursday along the south coast. Lows Wednesday night will range from around 60 across the higher inland terrain to around 70 along the immediate S coast as well as the urban centers. Last of the precip looks to push offshore Thu evening. Cooler air filters in as winds shift to NW up to around 10 mph, mainly along the coast and across the higher terrain. Overnight lows will fall back to the lower-mid 50s well inland to the mid 60s along the shore. Friday through Sunday...Moderate to high confidence. Large high pressure builds SE out of central Canada into the Great Lakes Friday, then slowly crossing the northeast U.S. next weekend. This will bring cooler temperatures especially during Friday and Saturday nights with mainly clear skies and light winds. Expect highs both Friday and Saturday mainly in the 70s, then warming to around 80 on Sunday. Could see some overnight lows in the mid- upper 40s across the E slopes of the Berkshires and the Worcester hills Friday morning. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through tomorrow night...High confidence. Mainly VFR outside of a few patches of fog late tonight and again tomorrow night at typically prone terminals. Winds W-NW today with a few gusts 20-25 kt. These weaken to near calm overnight. Sea breezes likely tomorrow on all coasts. KBOS Terminal...High confidence in TAF. KBDL Terminal...High confidence in TAF. Outlook /Wednesday through Friday/... Tuesday night...High confidence. VFR. Light S-SW or calm winds. Patchy fog late Tue night with local MVFR-IFR VSBYS. Wednesday...Moderate confidence. Mainly VFR. May see local MVFR conditions in scattered SHRA/TSRA across N central and W Mass during the afternoon. Wednesday night-Thursday...Moderate confidence. Mainly VFR. Local MVFR-IFR CIGS/VSBYS in scattered SHRA/isolated TSRA as cold front crosses the region into early Thu. Scattered showers may linger Thursday along the south coast before improving. Friday...High confidence. VFR. May see brief local MVFR VSBYS in patchy early morning fog across inland valleys of N central and NW Mass. Should improve quickly. && .MARINE... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Tuesday/...High confidence. Today...S-SW winds around 10 kt this morning become W-NW this afternoon, with gusts up to 20 kt possible near shore. Isolated showers possible through mid morning across the eastern waters. Southeast swells of 3-6 ft across the ocean waters. Tonight...N-NW wind with high pres building in from the west. Dry weather and good visibility. Southeast swells of 3-6 ft from Gaston persist. Tuesday...Light N-NE winds shift to SE during the day. S-SE swells from Hurricane Gaston continue across the outer waters. Outlook /Tuesday Night through Friday/... Tuesday night...High confidence. Expect light S winds. S-SE swells from Hurricane Gaston will be up to 5 ft, mainly across the outer waters. Small craft advisories will likely be extended. Visibilities may briefly lower in patchy late night fog mainly on the near shore waters. Wednesday...Moderate to high confidence. SW winds will gust up to 20 kt mainly across the eastern waters and near shore southern waters. Seas will remain at around 5 ft mainly on the eastern waters. May see local visibility restrictions early Wed morning in near shore patchy fog. Wednesday night-Thursday...Moderate confidence. A cold front crosses the waters with scattered showers/isolated thunderstorms into early Thursday morning. A few showers may linger through Thursday across the southern waters. SW winds gusting up to 20 kt Wed night will shift to NW and diminish Thu, then will shift to N-NE on the eastern waters Thursday afternoon. Seas linger at 5 ft on the eastern waters Wed night, then subside. Friday...High confidence. North winds gusting up to 20 kt over the open waters. Seas build up to 5-6 ft, with small crafts possible over the open waters. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 8 PM EDT Tuesday for ANZ250-254. Small Craft Advisory until 3 PM EDT Tuesday for ANZ255-256. && $$ SYNOPSIS...Belk/EVT NEAR TERM...Belk/Doody SHORT TERM...Belk LONG TERM...EVT AVIATION...Doody/EVT MARINE...Belk/EVT

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