Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 180341 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 1041 PM EST Wed Jan 17 2018 .SYNOPSIS... Snow showers will come to an end early this evening. Dry, but cold air will move into southern New England tonight and into tomorrow. Mainly dry weather expected tonight into Sunday, with a warming trend during this weekend. Another low pressure should affect the region early next week with mostly rain, but there is a risk of some snow/mix/ice across the interior. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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1020 PM Update... Spotty leftover snow showers and even some patchy freezing drizzle being reported across portions of E Mass at 03Z. Noting some very light radar returns, but those have been shrinking as they shift E over the last couple of hours. Light NW winds in place, and dewpts have been dropping across central and western areas, so feel that precip should taper off as it moves offshore through around midnight or so. Will still see some lower clouds lingering across SE Mass into RI as SW winds aloft linger through most of the overnight but, once the H5 cutoff low moves E off the mid Atlantic coast, should see winds shift as the lower clouds push offshore toward daybreak. Expect temps to steadily fall overnight across central and western areas, starting to reach into eastern areas after 2 AM or so as the clouds also push offshore. Temps will btom out in the teens inland, ranging to the 20s at the shore. Previous Discussion... Mid-level winds will shift to the northwest allowing for cold dry air to push into the region. Overnight temps will generally be in the teens with low 20s near the urban corridor and coastline. If temps at some inland locations decouple overnight, readings could drop quickly into the single digits thanks to fresh snow pack and mainly clear skies. Highest confidence is across ORE and BAF.
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&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... Thursday... Strong high pressure will build across the Mississippi Valley region pushing a coastal low off the Virgina coastline. Up here in the Northeast, flat ridge from the southern high pressure system will be in place. Continued westerly flow across the area as high temperatures will be near normal, reaching the upper 20s to mid 30s. Dry weather for the day with plenty of sunshine. Guidance is hinting at some ocean effect clouds moving in during the afternoon, as well as over the Berks from any LES. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... Highlights... * Dry with a warming trend through this weekend * Another storm may bring mostly rain late Monday into Tuesday with a risk of some interior snow/mixed precip/ice Quiet pattern expected through this weekend with a moderating trend as amplified trough moves into the Plains with downstream ridging and rising heights across New England. Near normal temperatures Friday, becoming above normal during this weekend. A deeper mid level trough is expected to approach southern New England early next week. This will steer a low pressure into the Great Lakes, and a cold front across our region. There is a decent southerly low level jet, so moisture transport should also be slightly higher than normal. Temperatures are marginal for wintry precipitation, so it will all come down to timing. The more precipitation which occurs during the nighttime hours, the more likely portions of our region could see a period of snow, sleet or freezing rain. During the daytime hours, rain is much more likely. Will take several days for these sorts of details to become clearer. && .AVIATION /04Z THURSDAY THROUGH MONDAY/...
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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 Thursday/... Overnight...High confidence. VFR across central and western areas. Lingering MVFR-IFR CIGS will slowly improving to VFR across NE Mass to greater Boston by around 05Z-06Z, but will linger until around 09Z or so across RI/SE Mass around 09Z or so. Thursday...High confidence. VFR. NW winds gusting up to 20 kts across S coastal areas, Cape Cod and the islands. KBOS Terminal...Moderate confidence in TAF. Improving conditions to MVFR by the evening with VFR after midnight. KBDL Terminal...High confidence in TAF. Conditions should start to improve within the next few hours as precip tapers off. Outlook /Thursday Night through Monday/... Thursday Night: VFR. Breezy. Friday: VFR. Friday Night: VFR. Windy with local gusts to 30 kt. Saturday: VFR. Windy with gusts to 35 kt. Saturday Night: VFR. Windy with local gusts to 30 kt. Sunday through Sunday Night: VFR. Monday: Mainly VFR, with local MVFR possible. Chance RA.
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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 Thursday/...High confidence. Coastal low will push into the Gulf of Maine tonight switching the winds to a more northwest direction. A few gusts to near 20 kts but overall winds will be below small craft criteria. Seas will remain at or above 5 feet through much of the period for the outer open waters. where Small Crafts will continue into Thursday evening. Have extended the Small Craft into the outer reaches of RI and BI sounds with 5 foot seas through mid morning Thursday. Outlook /Thursday Night through Monday/... Thursday Night: Winds less than 25 kt. Seas up to 5 ft. Friday: Winds less than 25 kt. Areas of seas approaching 5 ft. Friday Night: Low risk for Small Craft Advisory winds with local gusts up to 30 kt. Areas of seas approaching 5 ft. Saturday: Moderate risk for gale force winds with gusts up to 40 kt. Areas of rough seas. Saturday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft. Sunday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Monday: Winds less than 25 kt. Slight chance of rain.
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&& .HYDROLOGY...
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1100 AM Update... A Flood Warning remains in effect for the Connecticut River at Middle Haddam, where ice jams are causing river fluctuations. Cold conditions will persist through Thursday which will limit additional runoff. Continued ice jams will remain on some of the rivers. There will be some increase of snow pack across interior southern New England as well. For details on specific area rivers, including observed and forecast river stages, please visit the Advanced Hydrologic Prediction Service (AHPS) graphs on our website.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 10 AM EST Thursday for ANZ235-237- 251. Small Craft Advisory until 8 PM EST Thursday for ANZ250- 254>256.
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&& $$ SYNOPSIS...Belk/Dunten NEAR TERM...Belk/EVT SHORT TERM...Dunten LONG TERM...Belk AVIATION...Belk/Dunten/EVT MARINE...Belk/Dunten/EVT HYDROLOGY...Staff

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