Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 161752 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 152 PM EDT Mon Oct 16 2017 .SYNOPSIS... A sharp cold front exits Cape Cod and Nantucket early this morning. Behind the front, it turns sharply cooler and brisk this afternoon with temperatures then dropping down close to freezing by daybreak Tuesday. Gradual warm up begins Wednesday and continues into the weekend. After this mornings showers, dry weather prevails the remainder of the workweek and likely through the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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150 PM update... Bulk of the light showers/sprinkles south of New Eng but still may impact the islands next few hours. Otherwise, numerous high clouds streaming across New Eng ahead of approaching mid level trough along with some strato cu. Adjusted sky cover grids for a mostly cloudy afternoon. Temps mostly in the 50s to around 60 near the coast.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... Tonight... Leading edge of large high pressure will build east out of NY state tonight. The colder air over the milder waters will keep N winds stirring during the night, but as the pressure gradient relaxes, winds away from the coast will diminish especially after midnight. Some clouds will linger along E coastal areas through the night, also helping keep temps milder there. With mainly clear skies and the light winds, will see ideal radiational cooling away from the coast and urban centers. Temps will quickly tumble overnight and, with dewpoints falling to the upper 20s to lower 30s inland, will see temps drop as well. Expect areas of frost across many inland locations, with a few spots possibly bottoming out around the freezing mark. Have issued a frost advisory from 3 AM to 8 AM for most locations away from the coast and urban centers. Areas not included were N central and NW Mass where the growing season ended on Sunday. Expect lows in the lower-mid 30s in the advisory area, ranging to the 40s along the immediate coast, Cape Cod and the islands. Tuesday... As the high becomes firmly established across the region, winds along coastal areas will gradually diminish from about midday through the afternoon. Lingering clouds across the Cape and islands Tue morning will push offshore during the afternoon. Elsewhere, expect mostly sunny to sunny skies. Expect temps to top off in the 50s to around 60, running up to 5 degrees below seasonal normals. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... 355 AM update... * Highlights... - Warmer than normal this period with highs in the 70s Thu-Sat-Sun - Dry weather through the workweek and likely into the weekend * Synoptic Overview... Several low amplitude northern stream short waves ride the Canadian/US border this period. Given the lack of amplitude each trough is moisture starved. Thus very little if any sensible weather across southern New England this period with each short wave passage just providing a wind shift and a reinforcing surge of dry air. Tuesday night... Not as cool as Mon night as the high moves south of New England with low level WAA commencing as winds become WSW. Seasonably cool with lows 35-40, except in the 40s urban areas, high terrain, Cape & Islands. Dry weather prevails. Wednesday... Real nice day with 1028 mb high south of New England providing low level westerly flow advecting 925 mb temps of +11C across the region. This will support highs 65-70. Mild temps will be accompanied by light WSW winds and model RH cross sections suggesting lots of sunshine. Thursday... Next short wave trough moves across the northern Great Lakes into southern Ontario and Quebec. Good low level WAA ahead of this feature with 925 mb temps warming to +14C here in southern New England. These warm temps aloft combined with modest WSW surface winds and mostly sunny conditions will support highs in the low 70s away from the south coast. No precip expected, just a dry frontal passage given the lack of moisture associated with northern stream short wave. It will turn breezy as pres gradient tightens ahead of trough. Model soundings suggest SW winds gusting up to 25-30 mph. Friday... Not much thermal change in the post frontal airmass with 925 mb temps only cooling off to about +11C to +12C. High pres over the OH valley provides a well mixed blyr across New England with NW surface winds. This combination along with mostly sunny conditions will support highs 65-70. Another real nice day especially by late Oct standards. Next Weekend... Subtropical ridge builds over the southeast states into the Mid Atlantic region providing dry weather along with unseasonably warm temperatures here with highs well into the 70s especially Sunday. && .AVIATION /18Z MONDAY THROUGH SATURDAY/...
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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 Tuesday night/...High confidence. Through 00z...Mainly VFR cigs. Sct MVFR possible over the Berkshires and Cape/Islands. Tonight...VFR with gradual clearing. SCT-BKN low VFR/MVFR cigs possible over the Cape/Islands. N wind gusts to 20-25 kt Cape/Islands. Tuesday...VFR. N wind gusts to 20 kt across Cape/Islands in the morning, then diminishing. Tuesday night...VFR. Light winds turning SW. KBOS Terminal...High confidence in TAF. KBDL Terminal...High confidence in TAF. Outlook /Wednesday through Friday/...high confidence. 355 AM update... VFR, dry runways and good vsbys. WSW winds may approach 25 kt Thu.
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&& .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... Cold front pushes across Cape Cod and the southern waters this morning. Expect SW winds to shift to NW and gust up to 25 to 30 kt, but will briefly diminish around midday before picking up again this afternoon as colder air works across the waters. Scattered showers may produce brief visibility restrictions across the southern waters this morning. Small Craft Advisories on the outer waters have been extended into Tuesday. Winds and seas on the near shore waters will diminish during the day. Tonight and Tuesday... N-NW winds will gust to around 25 kt early tonight, then will diminish across the open waters. However, seas will remain at or above 5 ft through Tuesday, so Small Craft headlines will continue across the outer waters. Outlook /Tuesday Night through Friday/...Moderate confidence. 355 AM update... Overall quiet/tranquil boating weather by mid to late October standards. Only potential issue will be Thu when WSW winds may gusts up to 25 kt near shore ahead of an approaching weak/dry cold front. Otherwise good vsby and dry weather through the period. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...Frost Advisory from 3 AM to 8 AM EDT Tuesday for CTZ002>004. MA...Frost Advisory from 3 AM to 8 AM EDT Tuesday for MAZ005-006- 009>014-017-018-020-021-026. RI...Frost Advisory from 3 AM to 8 AM EDT Tuesday for RIZ001-003- 006. MARINE...Small Craft Advisory until 2 PM EDT Tuesday for ANZ250. Small Craft Advisory until 5 PM EDT Tuesday for ANZ254-255. Small Craft Advisory until noon EDT Tuesday for ANZ256.
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&& $$ SYNOPSIS...Nocera/EVT NEAR TERM...KJC SHORT TERM...EVT LONG TERM...Nocera AVIATION...Nocera/EVT MARINE...Nocera/EVT

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