Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 230921 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 421 AM EST Thu Nov 23 2017 .SYNOPSIS...
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Quiet weather through Friday with dry and cool conditions. Milder air returns Saturday ahead of a cold front, but will have to watch a coastal storm to the southeast. Blustery and cooler weather follows Sunday into Monday, then dry and milder conditions again Tuesday into Wednesday.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Chilly start to Thanksgiving as high pressure from the Great Lakes builds into the Mid-Atlantic. This will lead to dry weather and sunny skies to start the day. Northwest winds will begin to back to the west as flow aloft because a bit more zonal. This will warm 925mb temps closer to -1 to -2 C compared to the -5C we are starting out with this morning. This will help push temps into the upper 30s to low 40s. Weak shortwave aloft will increase cloud cover during the later half of the day. Moisture associated with this wave is meager enough to lead the forecast dry. Cross sections also support this with just high level clouds passing through. Overall, a chilly but dry Turkey day as temperatures will remain 5 to 10 degrees below normal.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
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Trough axis will push through the region this evening and slide to the north tonight. Mid to high level clouds will stream through as guidance continues to show some moisture for the first half of the night. 925mb jet will be on the increase along the passing wave resulting in a few gusts during the overnight hours. Best location is along the shoreline where waters will help increase the mixing. While the jet could limit radiational cooling, expect overnight inversion to limit the mixing across the interior. Aside from the cloud cover, dry weather will prevail. Expect temperatures in the mid 20s with metro region in the low 30s. High pressure will allow for dry weather once again on Friday. Developing ridge aloft will result in a more southerly flow. This will help push temps to be warmer than today. Highs should reach into the upper 40s to low 50s.
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&& .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
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Highlights... * Warming Sat with a low risk of showers * Blustery and cooler Sun/Mon * Turning mild again Tue/Wed with mainly dry conditions Overview... 23/00Z guidance suite is in good overall agreement through Saturday, then the detail differences start to become significant early next week. It will likely be a few more days before these differences resolve, when the energy involved gets better sampled by moving over North America. Have only moderate confidence in the details after Sunday. In general, expecting a variable temperature pattern, with near normal temperatures Saturday and the middle of next week. In between, below normal temperatures are anticipated. Mainly dry weather through this portion of the forecast. Low risk for some showers late Saturday into Saturday night as a cold front moves across southern New England. Moisture will be the main limitation, but thinking the greater risk will be towards the coast, where proximity to the ocean and interaction with an offshore low pressure may be enough to increase shower coverage. The forecast for the middle of next week remains uncertain. Current indications suggest a period of drier and warmer weather. However, large disagreements in the handling of a significant trough moving into the Pacific northwest Monday complicate the forecast through Wednesday. The resulting timing differences will mean the difference between a warm and dry Wednesday, or a cooler and wetter day.
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&& .AVIATION /09Z 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 Friday/...High confidence. Before 12z...Mainly VFR with MVFR mixing in early this morning. Clouds should begin to dissipate by 08-10z. NW winds will remain gusty over the next few hours until pressure gradient weakens towards day break. Today and tonight...VFR with westerly winds through the period. Friday...VFR with winds backing to the south but remaining light. KBOS Terminal...High confidence in TAF. KBDL Terminal...High confidence in TAF. Outlook /Friday Night through Monday/... Friday Night: VFR. Breezy. Saturday: VFR. Breezy. Slight chance SHRA. Saturday Night: VFR. Chance SHRA. Sunday through Monday: 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 Friday/... Tonight...High confidence. NW winds increase through the evening, with gusts mainly 25-30 kt across the waters into early tomorrow morning, there is a low risk for Gale gusts mainly on the outer waters, but these will be few and far between and only support a high end small craft advisory at this time. Seas will build with the increase in winds, peaking at around 8-9 ft on the SE outer waters. Tomorrow and tomorrow night...High confidence. Winds shift to the W, with gusts generally remaining below 20 kt after sunrise. Seas however will take some time to fully diminish, and will require small craft advisories to linger much of the day. Advisories have been extended for the outer waters into tomorrow night given 5 ft lingering swells are expected. Outlook /Friday Night through Monday/... Friday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Saturday: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers. Saturday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers. Sunday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Slight chance of rain showers. Sunday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Monday: Winds less than 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 10 AM EST this morning for ANZ231. Small Craft Advisory until 6 PM EST this evening for ANZ235- 237. Small Craft Advisory until 7 AM EST Friday for ANZ250. Small Craft Advisory until 1 PM EST Friday for ANZ254>256.
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&& $$ SYNOPSIS...Belk/Dunten NEAR TERM...Dunten SHORT TERM...Dunten LONG TERM...Belk AVIATION...Belk/Dunten MARINE...Belk/Dunten

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