Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 222324 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 724 PM EDT Thu Mar 22 2018 .SYNOPSIS... The coastal storm will move into the Maritimes tonight and linger through the weekend. Upper level disturbances moving into New Eng will bring the potential for scattered rain/snow showers through the weekend with temperatures remaining below normal. High pressure builds into the region Monday, then a warming trend is expected through the middle of the week. && .NEAR TERM /THROUGH FRIDAY/... 550 PM Update... Scattered light rain/snow showers lingering along Cape Ann and Cape Cod/Islands will diminish and move offshore during this evening. Then dry conditions expected for the overnight. Regarding winds and temps, a coastal front has set up, with the westernmost extent from LWM-BED-OWD-PVD. Temperatures were much cooler on the east side of this boundary, with temps in the mid 30s to low 40s. Utilized RAP/HRRR guidance for the next several hours which captures this boundary, updating winds/temp/dewpoint over the next few hours. Winds along the shoreline should shift over to the NW after 8 pm with the boundary washing out. Otherwise, weak shortwave ridging moving into New England combined with drying in the column will result in partial clearing, but clouds will return later tonight ahead of the next shortwave. Diminishing winds along the coast as storm moves further away. Lows will drop into the 20s in most locations. && .SHORT TERM /FRIDAY NIGHT/... Friday... Mid level low over the Great Lakes digs SE into New Eng late in the day. Deepening moisture moves in from the west which will bring increasing cloud cover back into SNE. A few rain or snow showers expected in the afternoon as low level lapse rates increase. Temps below normal in low to mid 40s, except upper 30s interior high terrain. Friday night... A few rain/snow showers may linger through the evening under the mid level low, otherwise lots of clouds will persist across the region. Lows will be mostly in the 20s. && .LONG TERM /SATURDAY THROUGH THURSDAY/... High pressure system builds down from Quebec this weekend advecting cold air over the region, keeping temperatures well below normal through early next week. Global models are hinting to a low pressure system that forms off the coast of the mid- Atlantic and quickly intensifies. At the moment, models suggest that the strong high over Quebec will keep the low pushed out to sea. Regardless, if the low remains in close proximity to our coast, winds and swell will increase and likely remain that way until another system pushes it further east. Otherwise, the high pressure will continue to build over the region through Wednesday, before giving way to an approaching cold front Thursday. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/...
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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 Night/... 2330Z Update... Tonight...Moderate to high confidence. Lingering MVFR on the Cape/Islands should improve to VFR by 03Z. Otherwise...VFR tonight. Friday...Moderate confidence. Mainly VFR, with local MVFR possible Cape/Islands. Isolated -SHRA/-SHSN possible. KBOS Terminal...Moderate confidence in TAF. VFR. E/Variable winds should shift to the NW by 02Z. KBDL Terminal...Moderate to high confidence in TAF. VFR. Outlook /Saturday through Tuesday/...Moderate Confidence. Saturday: Mainly VFR, with local MVFR possible. Slight chance SHRA. Saturday Night: Mainly VFR, with local MVFR possible. Windy with local gusts to 30 kt. Chance SHSN. Sunday: Mainly VFR, with areas MVFR possible. Windy with gusts to 30 kt. Slight chance SHSN. Sunday Night: VFR. Windy with gusts to 30 kt. Slight chance SHSN. Monday through Monday Night: VFR. Windy with gusts to 30 kt. Tuesday: Windy with gusts to 30 kt. Slight chance SHRA.
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&& .MARINE... Short Term /through Friday Night/...High confidence. Through tonight...Winds will gradaully diminish. Winds will drop below SCA over eastern waters this evening, but hazardous seas and SCA will continue for outer waters. Friday and Friday night...Northerly winds below SCA. Seas will gradually subside below 5 ft over eastern waters by Fri afternoon. Outlook /Saturday through Tuesday/...Moderate Confidence. Saturday: Winds less than 25 kt. Slight chance of rain showers. Saturday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Seas locally approaching 5 ft. Chance of rain showers, slight chance of snow showers. Sunday: Strong winds with gusts up to 30 kt. Areas of rough seas. Chance of snow showers, chance of rain showers. Sunday Night: Low risk for gale force winds with gusts up to 30 kt. Rough seas up to 10 ft. Chance of snow showers. Monday through Monday Night: Low risk for gale force winds with gusts up to 35 kt. Areas of rough seas. Slight chance of snow showers. Tuesday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Slight chance of rain showers. && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ232. Small Craft Advisory until 8 AM EDT Friday for ANZ231. Small Craft Advisory until 2 PM EDT Friday for ANZ250-254. Small Craft Advisory until 10 AM EDT Friday for ANZ251. Small Craft Advisory until 11 AM EDT Friday for ANZ255. Small Craft Advisory until 4 AM EDT Friday for ANZ256.
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&& $$ SYNOPSIS...KJC NEAR TERM...KJC/NMB SHORT TERM...KJC LONG TERM...Correia AVIATION...KJC/NMB MARINE...KJC/NMB is the U.S. government's official web portal to all federal, state and local government web resources and services.