065 FXUS61 KBOX 241529 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 1029 AM EST Sun Jan 24 2021 .SYNOPSIS... Cold and blustery this morning with possible sub-zero wind chills. Winds slacken Monday as high pressure builds into Southern New England. Though a couple periods of light snow are possible thru midweek, seasonable and dry weather generally prevails. A powerful area of low pressure near the mid- Atlantic waters on Thursday may bring breezy conditions to southern parts of MA and RI, though it looks to otherwise pass harmlessly to our south. A brief shot of much colder air then filters in for late in the week. && .NEAR TERM /THROUGH TONIGHT/... 1030 AM update... Forecast is on track this morning with no significant changes necessary. Temperatures haven't climbed out of the 20s with winds gusting 25 to 35 mph, locally higher. 615 AM Update: Quite cold and very dry out there early this morning, owing to gusty northwest winds with current temps in the teens (low 20s across Cape Cod). As of 6 AM, wind chills were running as low as the single digits below zero in parts of interior MA and northern CT, with single digit above zero readings being common. Certainly feels a lot more winter-like than days we're experienced so far in January. If you're headed outdoors this morning, make sure to dress appropriate for the cold weather. Forecast overall is holding up fairly well with no significant changes needed. Previous discussion: Not much change to the weather features today. Our region remains positioned between a low pressure over the Maritimes and a high pressure across the central Appalachians. This will maintain a cold and gusty northwest flow through most of today. Winds should become less gusty and strong late today as this high pressure edges closer to our region. Not seeing much moisture nearby. While there may be a few clouds over land, there will be plenty of sunshine. Clouds will be more of a feature across the outer coastal waters, where some ocean- effect clouds linger. High temperatures today are expected to be pretty close to what we saw yesterday, which will be slightly below normal. With the gusty winds, wind chills will be mainly in the single digits above zero and teens after daybreak. && .SHORT TERM /MONDAY/... High pressure to our west will become more of a factor in our weather. Dry and chilly weather continues, but winds will continue to diminish tonight into Monday Not ideal radiational cooling conditions tonight, but it will still be cold enough for most, and near normal for late January. Increasing mid and high clouds ahead of a warm front Monday, with near normal high temperatures expected. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Highlights... * Light, decorative snow Tue/Tues nite for western MA/CT. * Dry weather then prevails, but turning breezy on Thurs as a powerful cyclone near the mid-Atlantic waters passes well to our south. * Much colder air for Fri/Sat, potentially with low wind chills. Details: Monday Night into Tuesday Night: 500 mb height rises and sfc ridge will initally be in place Mon night. The mid-level height rises will shift a NW-SE axis of mid- level confluent flow to the north into ME/NH. Looking at mostly clear skies and dry conditions for Mon night with modest NE winds increasing slightly late. Lows mainly in the 20s. A deamplifying 500 mb shortwave trough is still progged to move into the lower Great Lakes Tues and into PA/southern NY Tues night. This feature will draw some moisture NE along a sfc warm front into western MA and parts of northern CT late Tues, and perhaps into central MA and RI Tues night. However a number of factors support the idea that this will likely be more of a decorative/mood snow at best. For one, weakening/deamplifying upper level energy won't support robust accumulation. The moisture that is available is rather limited, and some of that will have to initially go to top- down column saturation given initially dry air in place. Mid-level confluent flow over the eastern third of the CWA into ME/NH will also limit the eastern/northeast extent of precip. Will continue to focus highest PoPs (Chance range) from later Tues into Tues night for areas mainly SW of a Orange-Worcester-Providence line. GFS remains further north and is among the wettest guidance in terms of QPF, though did note the ECMWF increased its QPF a bit. Model QPF consensus is less than two-tenths of an inch, and part of this will go to saturating the column. With limited snow growth parameters as well, locally up to a couple inches of new snow accumulation, though most in western MA/CT into western RI will see coatings to an inch. Highs in the 30s, with lows in the 20s. Wednesday into Wednesday Night: High pressure returns for Wed, though some RH left behind will keep skies more partly to mostly cloudy. While most of the interior should be dry, may have some ocean effect precip for Cape Cod and adjacent coastal southeast MA later Wed into Wed night. Highs mainly in the 30s for most to near 40 for southeast New England. Lows mainly in the 20s. Thursday/Thursday Night: Models continue to advertise a well-defined shortwave disturbance moving through the mid-Atlantic region Thurs, which induces coastal cyclogenesis near the Carolinas/Chesapeake Bay area. Rapid deepening into a powerful (sub-980 mb) cyclone is reflected across most of the guidance, though good clustering in EPS/GEFS/GEPS ensemble member lows showing a progged track south and east of 40N/70W. While this cyclone looks to pass to our south thru Thurs night, fairly robust northerly pressure gradient between the cyclone's circulation and high pressure established over New England could lead to fairly breezy to gusty NE wind conditions. This is particularly the case the further south one goes. Have left populated NBM winds/wind gusts as is, which brings some 30 mph gusts to the South Coast and Cape Cod. Will have to see just how close the circulationg gets and how strong the cyclone deepens but could see a need to increase winds/gusts more than currently reflected. At the moment, breezy conditions and mostly dry weather (outside of ocean- effect precip for coastal MA) look to be the only effects for our area. Friday into Saturday: Potent closed low near Hudson Bay digs southward through New England on Friday. This feature looks to be associated with a strong shot of colder, modified-Arctic air. Advertised a dry forecast for now with limited moisture for this closed low to work with. However it turns quite cold with 925 mb temps plummeting to around -14 to near -20C on Fri into Fri night. Highs mainly in the 20s with lows single digits to teens, about 10 degrees below normal. With northerly winds around 15-20 mph through the night, we could be talking about low wind chills that could be worthy of headlines. Looks to be a brief period of below-normal temps though; while still below-average temps for Sat, the cold air mass does start to modify. && .AVIATION /16Z SUNDAY THROUGH THURSDAY/... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 12z TAF Update: Today through Monday: High confidence. VFR. Gusty NW winds continuing today up to 35 kt, then diminishing tonight into Monday. KBOS TAF...High confidence in TAF. KBDL TAF...High confidence in TAF. Outlook /Monday Night through Thursday/... Monday Night: VFR. Breezy. Tuesday: Mainly VFR, with local IFR possible. Slight chance SN. Tuesday Night: Mainly VFR, with local IFR possible. Chance SN. Wednesday: Mainly VFR, with local IFR possible. Wednesday Night: Mainly VFR, with areas IFR possible. Breezy. Slight chance SHSN. Thursday: MVFR/IFR conditions possible. Windy with local gusts up to 30 kt. Slight chance SHSN. && .MARINE... Gale force NW gusts continue this morning with rough seas and freezing spray across most of the waters. Threat of moderate freezing spray should diminish from south to north this morning. More freezing spray expected across the eastern coastal waters tonight into Monday morning. Gale force gusts expected to diminish this evening, at which time the Gale Warnings will be replaced with Small Craft Advisories. Seas will slowly subside tonight into Monday. Outlook /Monday Night through Thursday/... Monday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Tuesday: Winds less than 25 kt. Slight chance of snow. Local visibility 1 to 3 nm. Tuesday Night: Winds less than 25 kt. Local visibility 1 to 3 nm. Wednesday: Winds less than 25 kt. Wednesday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers, slight chance of snow showers. Local visibility 1 to 3 nm. Thursday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Slight chance of rain showers. Areas of visibility 1 to 3 nm. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...Wind Advisory until 1 PM EST this afternoon for MAZ022. RI...None. MARINE...Gale Warning until 9 PM EST this evening for ANZ231>235-237- 250-251-254>256. Gale Warning until 6 PM EST this evening for ANZ230-236. && $$ SYNOPSIS...Belk/Loconto NEAR TERM...Belk/Loconto/BW SHORT TERM...Belk LONG TERM...Loconto AVIATION...Belk/Loconto MARINE...Belk/Loconto