December 2022 Monthly Forecast: Shades of Winter Set to Appear for New England

The first weekday of a new month always brings a look ahead to the monthly forecast in our morning show on NBC10 Boston, simulcast on NECN, from 4 AM to 7 AM, and with December 1 the start of not only a new month, but also a new season, there’s plenty of attention on the upcoming forecast.  Things have changed when it comes to forecasting winter weather in New England – climate change has brought a rather dramatic, observable shift in how winter seasonal forecasts must be approached, and that’s just one of the topics our First Alert Weather Team will examine in depth in a half-hour climate change special, “Climate 2022,” airing Thursday evening at 7:30 PM on both NBC10 Boston and NECN.

LKS_30_DAY_FORECAST_TEMPS (5) LKS_30_DAY_FORECAST_TEMPS (5)Changes to the forecasting approach notwithstanding, Thursday’s look ahead to December came complete with hope for winter and snow lovers, even if no imminent storm threat is on the table.  Of course, right now New England continues in the throes of a pattern that’s only been able to deliver chilly air when it’s dry, warming repeatedly each time a storm approaches – and there’s good reason for that: the presence of a persistent, upper level storm packed with cold air over Central and Northern Canada has meant a storm track on the southern periphery of that cold, tracking across Southern Canada through Ontario and Quebec.  This has resulted in a series of warm and windy storms of mostly rain for the Eastern half of the United States, with frequent storms off the Pacific Ocean able to work with enough cold air for repeated heavy snow in the mountains of the Western U.S., but unable to reshape the jet stream winds aloft to sink farther south in the East.  The signs of changing that pattern are showing up even at the end of our First Alert 10-day forecast, with the large, swirling mass of cold air in Canada set to do two things: expand and drop slowly southeast.  This nearly ensures the pattern in the Northeast will turn markedly colder – from the Great Lakes to New England – for about a week and a half starting around Thursday, December 8.  It’s worth noting while this likely flip to colder-than-normal temperatures certainly raises the chance of snow getting involved with storms, it’s not a guarantee – storms may still carry enough warmth for Southern New England, in particular, to end up wet instead of white – but there’s no denying the foreseen mid-month pattern at least puts a much greater chance of wintry weather on the table, especially for Northern New England.  Temperatures in Boston average a daily high of 42°F and a low of 29°, so the combination of a warmer-than-normal pattern for the first week of the month, a likely colder-than-normal pattern for about 10 days after that, and oscillations either side of normal in the second half of the month have our team leaning toward a “near normal” temperature pattern in December.

LKS_30_DAY_FORECAST_PRECIP_ZOOM (5) LKS_30_DAY_FORECAST_PRECIP_ZOOM (5)December typically is a “wet” month – in quotations because this time of the year, precipitation is counted as all melted precipitation, rain and the amount of liquid when any snow is melted – with over four inches of precipitation typically falling over the 31 days, with nine inches of snow.  At this point, we’re predicting near normal values of both precipitation and snow for most of New England, excepting Cape Cod, where we’ve leaned drier-than-normal.  That said, this precipitation forecast is akin to threading a needle – with the changing jet stream pattern, it’s possible we find some opportunities for snow, but admittedly, it’s also quite possible disturbances that could trigger storms in this pattern miss by a narrow margin, leaving a snow drought – we just think there is an active enough jet stream and, for a time, enough available cold air that even one or two organized events could achieve the normal snow.  As for precipitation, we expect when storms do develop, they will tend to have northern displacement, putting heaviest precipitation amounts in interior Southern, Central and Northern New England, which is why we keep the Cape a bit drier.

What about the remainder of the winter?  Tune into Climate 2022 at 7:30 PM Thursday evening on both NBC10 Boston and NECN to get an idea for the modern, changed winter weather pattern, and I’ll follow up Friday morning with a post about the rest of the winter season!

Wintry Wind to More Mild Rain - Colder Pattern Seen Ahead

LKS_FRONTS_BOSDMA (49)Although the wind has come down in magnitude for New England Thursday, gusts still reach 40 to 45 mph, particularly in higher terrain, and while this may result in a few downed limbs and new power outages, the bigger impact is the blustery wind chill, making high temperatures in the lower 40s and 30s north feel like the 20s most of the day and likely causing occasional summit chairlift holds at some ski mountains.  This wintry feeling is accompanied by scattered snow showers in the mountains, and occasional flurries for the rest of New England as moisture blowing off the Great Lakes migrates east with the clouds able to survive under a cold sky.  As clouds melt away Thursday evening, the wind will gradually quiet, but still be steady enough for a wind chill in the 20s through the evening, including for tailgaters at Gillette Stadium, though by the time the Patriots and Bills kick off, the wind should be down to about 10 mph with a limited impact on the game, a continued wind chill in the 20s and an actual temperature of 34°.  Overnight lows in the 20s give way to a cool but fair day with a much lighter wind Friday, making high temperatures in the 40s feel decidedly better than Thursday.  In a busy weather pattern with a fast-moving jet stream aloft – the fast river of air, high in the sky, that steers storms and disturbances – the next storm comes calling on Saturday.  Much like its midweek predecessor, this storm will strengthen over Southern Canada, grabbing moisture from as far away as the Gulf of Mexico, and the counterclockwise wind flow around the storm center will deliver a strong southerly wind with mild air to New England on Saturday, ensuring the bulk of this storm’s precipitation falls as rain, even in the mountains of Ski Country.  Overall, Saturday’s wind gusts are unlikely to be as strong as Wednesday evening’s gusts to 50 and 60 mph, with most gusts on the order of 35 to 45 mph Saturday afternoon and evening.  The passage of a Saturday evening cold front will deliver another shot of drier and cooler air for Sunday, when a fair sky with high temperatures in the 40s will be accompanied by a fresh northwest breeze, but not a powerful wind.  Yet another mild storm system strengthens over Southern Canada early next week, returning showers and a relatively warm breeze to New England Monday night through Tuesday – but what follows is a change to the pattern.  For nearly two weeks our First Alert team has been advertising a colder weather pattern starting up in early December – we’ve pegged that transition as next Thursday in the 10-day forecast.  Though that certainly brings no guarantee following storms will be snow instead of rain for all of New England, it does mark a noticeable shift to wintry air and, therefore, certainly raises the chance of more snow involved with any storms that develop.

Some Power Outages Expected Late Wednesday as Wind, Rain Swing Through

LKS_FCST_WINDGUST_SWATH_NEWENG (12) LKS_FCST_WINDGUST_SWATH_NEWENG (12)An exceptionally quiet Tuesday belies the storm that’s organizing over the Central United States and headed for New England Wednesday.  For now, a nearly calm wind will spare New England from any wind chill factor, but the air is cool – highs of 40-45 degrees for most with sunshine generally dimming behind increasing clouds during the afternoon, though some pockets of ocean-effect clouds have been drifting on and off the coastline from the nearby ocean water.  Increasing Tuesday night clouds will prevent temperatures from bottoming out below the 30s and a strengthening south-southeast wind Wednesday will ensure temperatures around the Boston area are plenty warm enough for rain when isolated sprinkles and showers develop Wednesday morning, then become a steadier rain Wednesday mid-afternoon through evening, with rain departing overnight after dropping either side of half an inch.  In fact, the mild southerly wind will increase to gusts of 40-50 mph late Wednesday and Wednesday evening, with Cape Cod gusts of 50 to 60 mph a possibility – all of it enough for widely scattered pockets of wind damage and power outages.  Chances are good wind gusts will quiet below damaging levels by 8 to 10 PM for most of New England, perhaps a bit later along the Maine coast, but gusty wind will continue through the overnight and through Thursday, with gusts to 40 and 45 mph still possible.  All of this makes for a blustery Thursday, even though drier air will bring the return of sun, save for some scattered mountain snow showers and bursts of heavier snow from time to time in the high terrain.  The wind quiets substantially by Friday with dry weather but the next energetic weather system will be racing east toward New England, caught in a fast jet stream flow of wind aloft.  This next system arrives Saturday, delivering morning clouds and showers by afternoon, if not sooner, lasting into Saturday night.  It’s worth noting that our pattern of dragging milder air into New England ahead of each precipitation event looks to continue for much of the 10-day forecast, with colder air only very slowly building south through Quebec and Ontario, but eventually building a bit more formidably in Northern New England, raising the chance of snow in the North Country with each successive event.  Saturday’s won’t quite be cold enough for that, however, with rain expected regionwide, followed by another shot of fair and cool weather Sunday.  A string of disturbances will likely make for disturbed weather in the first half of next week – expected to be mild enough for raindrops, yet again, in Southern and Central New England but perhaps at least including some snow in the North Country by the time the string of disturbances have run their course by midweek.

Drier and Cooler Air Until Windswept Wednesday Rain Arrives

LKS_FRONTS_BOSDMA (48)Puddles and mild air started the return to work and school coming off the holiday weekend Monday morning, though a new air whipping in on a busy northwest breeze will serve to both dry and cool the air.  The drying happens quicker than the cooling, with early morning puddles shriveling under a blend of clouds and sun while temperatures starting in the 50s gradually slide to around 50° by midday, into the 40s by the time kids are headed home from school and even into the 30s north of the MA Turnpike by suppertime.  Combine this with winds gusting to 35 mph at times, and wind chill values will drop squarely into the 30s by evening and into the teens overnight, when the wind eases a bit but temperatures bottom out in the 20s.  On Cape Cod, the clash between chilly air aloft and relatively warm ocean water will mean some ocean-effect clouds Monday night, though little more than a sprinkle is anticipated to fall from those clouds.  Tuesday brings a fair sky and a nearly calm wind, though the cold start will likely cap afternoon high temperatures at 40-45 degrees, with clouds thickening late in the day and evening ahead of the next storm system.  That next storm hasn’t taken shape as of this writing beyond a slug of atmospheric energy, associated clouds and a cold front over the Northern Plains, but is forecast to organize and strengthen over the Midwest Tuesday, grabbing Gulf of Mexico moisture for an expanding area of rain over the Eastern U.S., arriving to New England first as clouds Tuesday evening and night, then as rain on Wednesday.  At this point, it looks like little more than an isolated shower will fall Wednesday morning, but Wednesday afternoon the rain fills in from west to east across New England, likely slowing the evening commute and lasting into the night.  It’s the rain’s combination with an increasing south wind gusting 40-50 mph that’s prompted a First Alert from our weather team for Wednesday evening.  Although widespread damage wouldn’t occur from wind of this magnitude, widely scattered damage may.  As the storm center crosses Southern Canada, the attendant cold front swings through New England overnight Wednesday night, exiting the rain east of us by Thursday morning and bringing the magnitude of wind down an order, but still promoting a blustery wind Thursday with the return of cool air that likely will leave some lingering mountain snow showers in the North Country.  Cool and dry air continues with a quieting wind Friday, in a familiar pattern that will only serve to repeat yet again twice more in the 10-day forecast: milder air arrives with showers by the latter half of Saturday into Saturday night, cooler and drier air follows Sunday and Monday, and mild air with raindrops yet again later Monday into Tuesday.  Each time, the chance of North Country mountain snow showers or snow bursts does increase as colder air streams back in, but right now a widespread snow event doesn’t seem to be in the cards.  That said, the nights will continue to be excellent for manmade snow, so the ski area base will continue to grow thanks to the technology!  That said, the jet stream pattern is in the process of tipping colder for the first half of December, so the chances of accumulating snow, especially in Northern New England, will rise, overall, as we get deeper into the new month.