795 FXUS61 KBOX 051058 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 658 AM EDT Tue Oct 5 2021 .SYNOPSIS... Low pressure along a frontal boundary off the south coast of New England will pass southeast of the area by this evening. Cool and moist north to northeast flow will persist across southern New England today. High pressure settling over New England on Wednesday brings clearing skies and milder than normal temperatures through Friday. A backdoor cool front ushers in cooler fall-like temperatures for the weekend. We will have to watch a wave of low pressure off this mid Atlantic coast, but thinking much of the rain may stay to our south through the bulk of the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 655 AM Update... Weak wave of low pressure south of the Islands will maintain low level NNE flow today. While deeper forcing has departed; lingering low level moisture was still resulting in scattered light showers and pockets of drizzle early this morning. We should see most of this activity wind down this morning as high pressure to our north ushers in somewhat drier air. That being said, clouds will linger today and we can not rule out a brief spot shower or two. However, once these remaining scattered light showers/drizzle depart by mid-late morning the majority of the day will feature dry weather with just an abundance of clouds. Previous Discussion Below: Low pressure south of New England will travel eastward along a stalled frontal boundary and will move well to our southeast by evening. Meanwhile, high pressure over northern Maine was extending southward toward Massachusetts. The combination of these two systems will lead to a continued cool, moist north to northeast flow over the area today. While the bulk of the rain will be offshore, there still could be a lingering light shower heading southeastward across mainly northern and eastern MA into this afternoon. Abundant low level moisture will keep it overcast almost all day. However, toward evening, there could be some partial clearing sneaking southward into northern MA. With the cloudiness and northeast flow, highs today will only reach 55-60 north and 60-65 south. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... 320 AM update... Tonight... As high pressure builds in from the north, drier air moves in and skies will clear from north to south. Cape Cod and the Islands may remain cloudy most of the night, however. North wind in the interior will diminish to near calm, but it will still be a bit gusty to 10-20 mph at the coast. Lows will be in the upper 40s to lower 50s except mid and upper 50s on Cape Cod/Islands. Wednesday... High pressure will be in full control. Looks like a splendid fall day with sunshine, light wind, and highs reaching the upper 60s to lower 70s. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Highlights... * Mainly Dry Weather likely persists through much of the weekend * Rather mild Thu/Fri with highs in the 70s * Cooler onshore flow should keep highs mainly in the 60s Sat & Sun Details... Upper level ridging coupled with high pressure overhead will result in dry and very pleasant early October weather for Thu and Fri. Cool/pleasant nights will be followed by rather mild days with above normal temperatures. 925T near +14C coupled with a dry airmass in place should allow afternoon high temps to reach well into the 70s in many locales Thu/Fri. Light winds will make it quite comfortable outside during the afternoon hours. Surface high pressure over eastern Canada will then drop south into eastern New England this weekend allowing a backdoor cold front to cross the region. This coupled with some sort of low pressure system to our south will generate cooler/onshore flow. This will keep high temps mainly in the 60s this weekend and it will be a touch breezy along the coast on Saturday. Limited upper level support will probably result in most of the weekend being dry. However, a few ensemble members do show some showers being pulled northward into our region from the wave of low pressure to our south. Still too early to say if this happens, but given limited upper level support thinking main impacts this weekend will be a period of clouds rolling in off the ocean with perhaps a few light showers/drizzle. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 12Z TAF Update: Moderate confidence today and tonight. High confidence Wednesday. Today MVFR to IFR conditions dominate with the lowest conditions towards the southeast New England coast. Ceilings should improve slowly from north to south as the day wears along. In fact...ceilings may improve to VFR toward evening across parts of northern MA. NE winds gusting to 10-20 kt along the coast. Otherwise patchy drizzle and fog until mid morning. Can't rule out a shower in MA into this afternoon, but mainly dry. Tonight...Conditions improving to VFR across much of eastern MA/RI from north to south. Lower conditions may linger all night over Cape Cod/Islands and may see some low clouds/fog fill back in across parts of interior MA and CT. N wind near calm interior but gusting to 10-20 kt at the coast. Wednesday... VFR. Light wind. KBOS Terminal...Moderate confidence in TAF. Mainly MVFR conditions, but some IFR cigs are possible for a time this morning. KBDL Terminal...Moderate confidence in TAF. Outlook /Wednesday Night through Saturday/... Wednesday Night through Friday: VFR. Friday Night through Saturday: Mainly VFR, with local MVFR possible. Breezy. Slight chance SHRA. && .MARINE... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 320 AM update... High confidence through Wednesday. Low pressure south of New England will pass southeast of the region late this afternoon and evening. High pressure over Maine will become centered over southern New England on Wed. Persistent E to NE winds shifting to the N tonight and continuing Wed. Winds will gust up to 25 kt over the southeastern waters today into this evening. Winds gusting to 10-20 kt over the southeastern waters later tonight and 10-15 kt Wed. Small Craft Advisories are in effect for the southeastern outer waters, where winds may gust to 25 kt today and seas will be near 5 ft. Winds diminishing and seas slowly subsiding to below SCA criteria southeast areas tonight. Outlook /Wednesday Night through Saturday/... Wednesday Night through Friday: Winds less than 25 kt. Friday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers. Saturday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 6 AM EDT Wednesday for ANZ254. Small Craft Advisory until 1 AM EDT Wednesday for ANZ255-256. && $$ SYNOPSIS...GAF/Frank NEAR TERM...Frank/GAF SHORT TERM...GAF LONG TERM...Frank AVIATION...GAF/Frank MARINE...GAF/Frank