000 FXUS61 KBOX 180135 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 935 PM EDT Wed Apr 17 2024 .SYNOPSIS... Increasing cloud coverage this afternoon, rain chances increase during the overnight hours mainly across western Massachusetts and northern Connecticut. Cloudy, much cooler, with scattered light rain continuing for Thursday. Dry and seasonable for much of Friday with high pressure in control. A cold front brings another round of light rain showers Friday night into Saturday morning. Dry for the rest of Saturday with gusty winds. The dry stretch of weather continues into early next week with the next chance of wet weather Tuesday night and Wednesday as a frontal system approaches. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 935 PM Update... * Showers mainly southwest of an ORE-PVD-ORH line overnight * Low temps in the lower to middle 40s Previous forecast is on track. 850 MB warm front will generally remain across southwest MA & CT overnight with a mid level ridge axis blocking its eastward progress. This will confine most of the showers to the southwest of an ORE-ORH-PVD line overnight. To the east of this region...nothing more than perhaps a few brief light showers/sprinkles with the majority of the overnight hours featuring dry weather. The clouds will keep low temps mainly in the lower to middle 40s. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... Highlights: * An easterly wind will lead to a much cooler day, a few showers are possible, though a washout is not expected. Mid-level ridge for Thursday, though a shortwave passage will bring our a few showers, not a washout by any means. At this point, kept POPs around 30 ~ Chance Rain. The more noticeable difference is the east wind, allowing for a raw/cool feel. High temperatures along the immediate coast are in the middle to upper 40s. Elsewhere, highs are lower and middle 502. Higher elevations in western Massachusetts are the coldest in the lower 40s. East wind are 10 to 15 mph, with gusts along the coast to 25 mph. Precipitation chances come to an end overnight, though clouds and on shore flow does continue into the overnight hours. Do think spots along the eastern coast could see spot drizzle, but didn't have the confidence to include it in the WX GRID. Guidance this afternoon remained split on how much low level moisture would linger, so OPT to leave it out. Similar to the night before, our temperatures are in the upper 30s and low 40s. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Key Points... * Mainly dry and seasonable Friday * Scattered showers Fri night into early Sat followed by mild and breezy conditions Sat afternoon * Dry conditions return for Sun into Tue. Cooler Sun, then milder Mon and Tue * Shower chances increase by Wed Details... Friday into Saturday... Mid level shortwave departs by early Fri with weak shortwave ridging following. This will bring dry conditions for much of the day, although next shortwave and cold front will be approaching from western NY in the afternoon. We should see some sunshine develop, especially in eastern New Eng but trend will be for increasing cloud cover in the afternoon. Low risk a few showers could spill into western MA by days end but bulk of shower activity should hold off until Fri night. Near normal temps Fri. Weak cold front moves into SNE Fri night with modest increase in moisture as PWATs increase to near 1" ahead of the front. This should bring a round of scattered showers Fri night which will likely linger into Sat morning, especially in the east as the front gets hung up near the coast. Then drying out in the afternoon with somewhat gusty W winds developing in the afternoon. Given the colder airmass will be lagging to the NW assocd with a secondary cold front, it should be a mild afternoon with temps reaching the 60s, and some upper 60s possible in SE MA. This secondary cold front is tied to a decent shortwave passage late Sat-Sat evening. The column is drying at this time but there may be a brief window for a few showers with the front late Sat in the interior. Did not include in the forecast at this time as confidence is low, but will re-evaluate in later forecasts. Sunday through Wednesday... Cooler post-frontal airmass settles in on Sunday with seasonable temps and abundant sunshine. Dry weather continues Mon and Tue with moderating temps. A potent shortwave is forecast to move off the mid Atlc coast Mon night-Tue but global ensemble guidance keeps moisture well to the south with a minimum in PWATs across SNE. Next northern stream shortwave approaches from the west Tue night and Wed. Timing and amplitude of the system is uncertain but risk for showers will increase by Wed. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Forecast Confidence Levels: Low - less than 30 percent. Moderate - 30 to 60 percent. High- greater than 60 percent. 00z TAF update...no changes. Tonight and Thursday...High Confidence. MVFR ceilings and light showers develop tonight across western MA/CT with the best chance near and west of the CT River. These conditions will persist at times into Thursday. Meanwhile, across eastern MA/RI mainly VFR conditions are expected. Light southeast winds tonight becoming east between 5 and 10 knots on Thursday. Thursday Night...High Confidence. Lower end VFR and MVFR. Showers end, but areas of drizzle could develop along the coast. East wind 5 to 10 knots. KBOS TAF...High confidence. VFR for the TAF period. East wind the rest of today, becoming southeast overnight. While VFR on Thursday, CIGS are 050-070 along with a low chance of a spot shower. Left the mention out of the TAF do to the lower confidence. Wind becomes east once again Thursday around 10 knots. KBDL TAF...High confidence. VFR this evening, becoming MVFR around 04z with -SHRA through 10z. Light southeast wind becoming east/southeast by daybreak. MVFR/low end VFR Thursday with spot showers possible and east/northeast wind around 10 knots. Outlook /Friday through Monday/... Friday: Mainly VFR, with local MVFR possible. Breezy. Friday Night: Mainly VFR, with local IFR possible. Breezy. Chance SHRA. Saturday: VFR. Breezy. Slight chance SHRA. Saturday Night through Sunday Night: VFR. Breezy. Monday: VFR. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Tonight through Thursday Night...High Confidence. * Small Craft Advisory for Block Island Sounds and waters south of Block Island tonight and into Thursday. A weak wave of low pressure drops southeast across the mid- Atlantic with high pressure moving across the eastern Canadian Maritimes into Thursday. A few spot showers and perhaps a rumble of thunder possible. This will result in SE winds this evening shifting to the E by Thursday morning at speeds of 10 to 15 knots. Some gusts up to 25 knots with marginal 5 foot seas for the southwest waters, hence the newly issued Small Craft Advisory through much of Thursday. Seas may remain elevated enough to warrant the advisory to be extended into Thursday night for the waters south of Block Island. Future forecasts may want to include this. Outlook /Friday through Monday/... Friday: Winds less than 25 kt. Seas locally approaching 5 ft. Friday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers. Saturday: Winds less than 25 kt. Chance of rain showers. Saturday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Sunday through Monday: Winds less than 25 kt. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 5 AM to 5 PM EDT Thursday for ANZ237. Small Craft Advisory from 5 AM to 8 PM EDT Thursday for ANZ256. && $$ SYNOPSIS...KJC/Dooley NEAR TERM...Frank SHORT TERM...Dooley LONG TERM...KJC AVIATION...KJC/Dooley MARINE...KJC/Dooley