Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 140824 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 324 AM EST Tue Nov 14 2017 .SYNOPSIS...
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Spotty light rain and/or drizzle early this morning gives way to mainly dry weather this afternoon and remaining cooler than normal. A fast moving cold front will bring a few showers late Wednesday night and Thursday morning, then dry, chilly and blustery weather follows Friday. A period of snow showers at higher terrain is possible Saturday morning, followed by a chance of widespread rain Saturday afternoon. Mainly dry and cooler weather should return on Sunday.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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330 AM update... Mid level trough now offshore with surface low over Georges Bank and moving farther out to sea. Short wave ridging building in from the west however 1030 mb high over Quebec and offshore low providing moist NNE flow into the region. Lots of low level moisture trapped beneath this subsidence inversion and resulting in spotty light rain/drizzle early this morning. Temperatures remain above freezing however a few of the higher elevations are near 32, so there could be some icy spots from freezing rain/drizzle and/or black ice from leftover residual moisture. Will continue with the special weather statement to highlight potential icy spots. Otherwise short wave trough exiting the Great Lakes this morning swings across southern New England. Not much mid/upper level moisture with this feature, so other than a spot rain shower/snow shower high terrain, mainly dry weather is expected later this morning into the afternoon. It will remain cooler than normal as mostly cloudy skies prevail along with cool 1030 mb high pres over the region precluding shallow cool airmass from mixing out. Highs only in the 40s, upper 30s across the high terrain. Normal temps for 11/14 should be in the low 50s.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
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330 AM update... Tonight... Mid level trough moves offshore with flow becoming anticyclonic overnight, resulting in clouds eroding. Thus dry cool weather prevails. Wednesday... Short wave ridging and its associated anticyclonic flow moves across the area, drying the column and yielding mostly sunny conditions. The exception may be along the south coast where clouds may linger. Cool airmass remains over the area with surface ridge remaining over New England. Temps remain cooler than normal with highs only in the 40s. However it won/t feel as cold given full sunshine and light winds.
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&& .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Highlights... * Mainly dry and cool Wed * A period of scattered showers early Thursday AM * Light snow showers at higher terrain Sat AM * Widespread rainfall likely Sat afternoon into Sun AM * Dry and colder weather likely returns by Sun Details... Wednesday... High pressure builds down from over Southeastern Canada into New England. Northerly winds will make for below normal temperatures once again as highs struggle to reach into the 40s across much of the region. Wednesday night and Thursday... Models are suggesting rain showers will move into the region by 06z, ahead of the approaching system. Rainfall amounts will be light, generally 0.10" or less. As a cold front associated with the system progresses across Southern New England, it will push the 540 thickness line just south of the islands. Fortunately the surface temperatures will be too warm, with highs near 50, for any frozen precip to reach the ground Thursday afternoon. Rain showers will likely end by 00z Friday as the cold front finally moves offshore. Thursday night and Friday... Winds will pick up behind the front Friday, keeping temperatures in the low 40s through Friday afternoon. Northwesterly winds may gust up to 35 mph along the southeastern coast of New England. Friday will be mostly dry throughout the afternoon as high pressure briefly builds into the region. Expect mostly sunny skies Friday afternoon. Saturday... Models have continued to trend slower with the next system approaching from the west. Decided to follow the slower ECMWF guidance, since the GFS remains a fast outlier. As the system approaches from the west, widespread precip is likely throughout Saturday. With the early morning low temperatures, snow showers are possible across western and central Massachusetts before 15Z. As temperatures warm into the upper 40s/low 50s, precip will change over to rain showers for the remainder of the day. Uncertainty remains with the timing and precip type, especially in the morning hours. Sunday... A cold front moves across the region early Sunday morning. Light snow showers are possible once more Sunday morning, but mostly across the higher terrain. Precip will dissipate by late morning as dry air pushes into the region. Winds are likely to pick up along the Cape and Islands behind the cold front, gusting up to 30 mph out of the southwest. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Wednesday/... 06z UPDATE...moderate to high confidence. Through 12z... A mix of IFR/MVFR in spotty light rain/drizzle. Most locations remain above freezing but CT river valley and highest elevations may experience temps at or just below freezing, thus brief spotty light freezing rain/drizzle across this area. Modest NE winds across southeast MA including Cape Cod and Islands. After 12z... Mix of IFR/MVFR will begin trending upward 12z-15z to MVFR-VFR. Spotty light rain/drizzle possible at 12z but trends will be toward drier weather as the day progresses. Modest NNE winds continue across southeast MA including Cape Cod and Islands. Tonight and Wednesday... Dry weather and VFR but MVFR may linger across southeast MA including Cape Cod and the Islands. Light winds. KBOS Terminal...moderate to high confidence in TAF. KBDL Terminal...Moderate to high confidence in TAF. Outlook /Wednesday Night through Saturday/...High confidence. Wednesday Night: Mainly MVFR, with areas VFR possible. Chance SHRA. Thursday: Mainly VFR, with areas MVFR possible. Breezy. Chance SHRA. Thursday Night: VFR. Windy with local gusts to 30 kt. Friday: VFR. Breezy. Friday Night: Mainly VFR, with local IFR possible. Slight chance SHSN. Saturday: Mainly MVFR, with local IFR possible. Breezy. SHRA likely. && .MARINE...
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Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Wednesday/... Today and Tonight...high confidence. NNE winds 10 to 20 kt with 3 to 4 ft seas across eastern MA waters, less than 3 ft elsewhere. Spotty light rain/drizzle this morning otherwise dry weather and good vsby. Wednesday...high confidence. High pres builds over New England resulting in light winds, dry weather and good vsby. Tranquil weather by mid Nov standards. Outlook /Wednesday Night through Saturday/... Wednesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Rain showers likely. Thursday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Rain showers likely. Thursday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Friday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Friday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers. Saturday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Rain showers likely.
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&& .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...Nocera NEAR TERM...Nocera SHORT TERM...Nocera LONG TERM...Correia AVIATION...Nocera/Correia MARINE...Nocera/Correia

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