Area Forecast Discussion
Issued by NWS Boston, MA

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918 FXUS61 KBOX 170014 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 714 PM EST Sat Dec 16 2017 .SYNOPSIS... Blustery and cold conditions today with less wind Sunday as high pressure builds across the region. A weak wave of low pressure may bring spotty light snow showers to the region late Sunday night into Monday morning. Temperatures will be milder on Tuesday ahead of a cold front, then turning blustery and colder Wednesday into Thursday. A wave of low pressure which may track to our west will bring the potential for a wintry mix/rain sometime Friday and/or Saturday. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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710 pm update... Scattered light snow showers/flurries have pretty much exited the south coast early this evening. There were a few more brief flurries/snow showers dropping down into northern MA, but this activity should wind down in the next hour or two. Drier air working in from the northwest should allow skies to become mainly clear from north to south through midnight. Very cold temperatures will also be ushered into the region overnight behind the cold front. Winds should gradually diminish overnight allowing the coldest outlying locations to drop into the single digits by daybreak especially with snow cover. The rest of the region should see overnight lows drop well down into the teens.
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&& .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... Sunday into Sunday night... High pressure north of the region will continue to build into tomorrow. This will result in light winds and mostly clear skies. A chilly start to the morning with temps rebounding into the upper 20s to low 30s. Despite weak WAA during the later half of the day, still enough shallow cold air to keep temps cooler than today. Clouds will build within the WAA pattern during the later afternoon into evening hours. Surface low pressure system moving into the Great lakes with warm front extending towards the northeast. High pressure remaining to our north will keep winds light during the overnight hours. However with clouds thickening during the late evening, radiational cooling will be limited resulting in lows in the teens and low 20s. Increasing threat-e ahead of the warm front could be enough for a few snow showers towards the early morning. Models are indicating very little in the way of QPF and with not a lot of lift, will keep the potential at a chance for now. && .LONG TERM /MONDAY THROUGH SATURDAY/...
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Highlights... * Lingering spotty light snow showers possible into Mon AM * Low risk for spotty freezing drizzle northern and esp NE MA Mon PM * Mainly dry and much milder Tue * Blustery and colder with mainly dry weather Wed into Thu * Period of wintry mix/rain possible sometime Fri and/or Sat Details... Monday morning... Moisture and weak lift may be enough for a bit of lingering spotty light snow showers into Monday morning. Limited moisture/forcing will should keep any accums to a dusting to no more than an inch. Monday afternoon and night... Somewhat of a tricky forecast Monday afternoon and night. Low clouds will likely hang tough on Monday. Temps should climb above freezing Monday afternoon to the south of the MA turnpike with readings reaching well into the 30s to the lower 40s. North of the MA turnpike, temps will struggle to climb much above freezing. In fact, some of the guidance shows a weak meso-low lifting northeast of the region. This may allow temps to fall a bit across parts of the area during the afternoon, especially northeast MA where some guidance has readings in the 20s by early evening. Not sure if there will be enough left over low level moisture for any precip, but can not rule out the low risk for spotty freezing drizzle or flurries in north and especially northeast MA Mon PM. Something will have to watch closely though given just trace amounts of spotty freezing drizzle can be problematic. Tuesday... Westerly flow aloft, 850T near -2C and decent mixing should push high temps well up into the 40s to perhaps even near 50 in a few locations along the coastal plain. Mainly dry weather anticipated as synoptic forcing is limited, but can not rule out a few showers in the afternoon across western MA as a cold front approaches. Tuesday night and Wednesday... A cold front will cross the region Tue night into early Wed with perhaps a few brief rain/snow showers. High temps will recover well into the 30s to around 40, but a well mixed atmosphere should result in northwest wind gusts of 30 to 40 mph developing Wednesday and making it feel colder. Thursday... Mainly dry and cold weather continues but with less wind than on Wednesday. High temps will be held mainly in the lower to middle 30s. Friday and Saturday... Low confidence forecast as always given time range but even more complicated by the pattern. Model guidance has a classic La Nina pattern with upper level ridging over the southeast U.S., resulting in above normal temps in that region. Meanwhile, arctic air will be sitting across eastern Canada. This will put our region in the battle ground with a wide range in possible temperature outcomes and ptypes. Based on the current guidance an initial wave of low pressure appears like it will track west of the region Fri into Sat. Assuming that happens, ptype would either be mainly rain or snow/ice transitioning to mainly rain. Of course a lot can change between now and that time, and given the large temperature gradient that will be setting up across the eastern U.S. would not put to much into a deterministic forecast this far out.
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&& .AVIATION /00Z SUNDAY THROUGH THURSDAY/...
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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 Sunday Night/...High confidence. Overnight and Sunday...VFR conditions other than a brief spot snow shower possible through 02z. Sunday night...VFR to start with MVFR conditions expanding from south to north towards daybreak. Chance of snow showers during the overnight. KBOS Terminal...High confidence. KBDL Terminal...High confidence. Outlook /Monday through Thursday/... Monday: Mainly VFR, with areas MVFR possible. Chance SHSN, slight chance FZDZ. Monday Night: Mainly VFR, with local MVFR possible. Slight chance FZDZ. Tuesday: Mainly VFR, with local MVFR possible. Windy with areas gusts to 30 kt. Slight chance SHRA. Tuesday Night: VFR. Windy with gusts to 30 kt. Slight chance SHRA. Wednesday: VFR. Windy with gusts to 35 kt. Wednesday Night: VFR. Windy with local gusts to 30 kt. Thursday: VFR. Breezy.
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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. Short Term /through Sunday Night/...High confidence. Tonight...W-NW gusts to 25-30 kt lingering into this evening before diminishing after midnight. SCA all waters. Sunday and Sunday night...Light NW winds with seas below SCA. Outlook /Monday through Thursday/... Monday: Winds less than 25 kt. Chance of snow showers, slight chance of rain showers. Monday Night: Winds less than 25 kt. Tuesday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Slight chance of rain showers. Tuesday Night: Low risk for gale force winds with gusts up to 30 kt. Local rough seas. Slight chance of rain showers. Wednesday: Low risk for gale force winds with gusts up to 35 kt. Areas of rough seas. Wednesday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Thursday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas locally approaching 5 ft.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 1 AM EST Sunday for ANZ231>234-251. Small Craft Advisory until 3 AM EST Sunday for ANZ235-237-250. Small Craft Advisory until 8 AM EST Sunday for ANZ254>256.
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&& $$ SYNOPSIS...Dunten/Frank NEAR TERM...Frank/Dunten SHORT TERM...Dunten LONG TERM...Frank AVIATION...Dunten/Frank MARINE...Dunten/Frank

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