Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 151855 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 255 PM EDT Fri Mar 15 2024 .SYNOPSIS...
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Drying out on Saturday with unseasonably mild temperatures away from the immediate coast. Round of showers Sunday morning with the passage of a cold front. Temperatures trend cooler next week along with gusty winds and near daily chances for isolated showers.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Drying trend is already underway across southern New England, with vast majority of the lingering showers offshore. Clouds have been stubborn, with what little sunshine we had across CT, RI and southeast MA late this morning quickly filling in early this afternoon. Winds have turned north already, and will continue to flip around to the northwest, and eventually the W overnight. This could bring some clearing to portions of the CT River valley after midnight. With rather light winds and plenty of clouds, not expecting strong radiational cooling or cold air advection tonight. Thus, low temperatures should come in as above normal.
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&& .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
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A weak high pressure should be centered over the Mid Atlantic coast Saturday, then move offshore Saturday night. This will open the door for a low pressure to move across eastern Canada, pushing its cold front across southern New England Sunday. Mainly dry Saturday with some sunshine developing during the day. While not full sunshine, there should be enough to boost high temperatures above normal region-wide. Light pressure gradient should also result in localized sea breezes along the coast. There is some question as to when. Without the full sunshine, thinking this should be more on the later side of the sea breeze window. Clouds increase Saturday night, with an increasing risk for some rain showers after midnight. Much like today, the greatest risk for these showers is expected across northern MA.
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&& .LONG TERM /SUNDAY THROUGH FRIDAY/...
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Key Points * Temperatures trend cooler this week * Daily chances for showers and light graupel through Wednesday Sunday Cold front swings through the region Sunday morning bringing a quick round of showers along the front. Otherwise Sunday afternoon is trending drier as a dry slot behind the front works in. Winds along the cold front could be quite gusty up to 20-35mph out of the WSW. Winds calm down briefly overnight before becoming gusty again Monday. High temperatures top out in the mid to upper 50s where sun can be realized, but if clouds end up lingering, highs will stay in the low 50s. Monday - Wednesday Stuck under cyclonic flow and cold pool aloft, temperatures begin to trend cooler with daily chances for diurnal showers. Steep low level lapse rates each afternoon of 8-10C/km and moderately steep mid level lapse rates of 6-8C/km, combined with the strong March sun angle, will lead to isolated convective showers. With 850mb temps dropping from -5C to -10C during this time period, any graupel that these low topped convective showers produce could reach the ground esspically across the high terrain. Did push POP`s up each afternoon to force isolated/slight chance showers. Winds remain gusty through this period with a tight pressure gradient bringing NNW winds gusting 25-35 mph. It will feel much cooler this week compared to last week as cold air advection will leave highs only in the mid 40s by Tuesday. With the gusty winds, the wind chill factor will only make it feel like the 20s and 30s by Tuesday and Wednesday. Thursday and Beyond. Weak upper level ridge brings rising heights and quick moving high pressure Thursday before some models indicate a shortwave exiting out of the Great Lakes. Given this is a week out, there is large spread among the different model and ensemble systems. Won`t speculate more then the next chance for more substantial precipitation could be late next week or weekend.
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&& .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
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Forecast Confidence Levels: Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Tonight...High Confidence in trends. Moderate confidence in timing. Mainly MVFR ceilings will linger this evening across eastern New England, but VFR conditions overspread this region from the west as the night progresses. Light and variable winds. Saturday...High Confidence. VFR, except for some lingering IFR across the Cape and Nantucket early. SW winds 5-10 kt, but localized sea breezes developing during the afternoon along portions of the immediate coast. Saturday Night...High Confidence. Mainly VFR, with increasing areas MVFR after 17/midnight EDT. Local IFR across the higher terrain towards daybreak Sunday. KBOS TAF...High confidence in trends. Moderate confidence in timing. KBDL TAF...High confidence in trends. Moderate confidence in timing. Outlook /Sunday through Wednesday/... Sunday: Mainly VFR, with local IFR possible. Breezy. Chance RA. Sunday Night: VFR. Breezy. Monday: VFR. Breezy. Slight chance SHRA. Monday Night: VFR. Breezy. Tuesday: VFR. Breezy. Slight chance SHRA. Tuesday Night: VFR. Breezy. Wednesday: VFR. Breezy. Slight chance SHRA.
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&& .MARINE...
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Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Low pressure departs with diminishing winds this evening. Seas will take a little longer to subside. Will permit Small Craft Advisories to eventually expire tonight into Saturday. Otherwise, good visibility with rather light winds expected into Saturday evening. Increasing winds Saturday night should also result in building seas across the southern coastal waters of MA and RI. Outlook /Sunday through Wednesday/... Sunday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Chance of rain. Sunday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Monday: Winds less than 25 kt. Seas locally approaching 5 ft. Monday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Tuesday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft. Slight chance of rain showers. Tuesday Night: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Seas up to 5 ft. Wednesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Slight chance of sleet.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 7 PM EDT this evening for ANZ231- 250-251. Small Craft Advisory until 10 PM EDT this evening for ANZ232. Small Craft Advisory until 4 AM EDT Saturday for ANZ254-256. Small Craft Advisory until 7 AM EDT Saturday for ANZ255.
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&& $$ SYNOPSIS...Belk/KP NEAR TERM...Belk SHORT TERM...Belk LONG TERM...KP AVIATION...Belk/KP MARINE...Belk/KP

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