The cold has eased significantly across New England today but while the thermometer will measure high temperatures near 40° south and 30° north Wednesday afternoon, the increasing southwest wind carrying this milder air into New England has the ironic effect of creating a wind chill to somewhat offset with wind chill values never breaking above the 20s south and teens north. Gusts from the southwest have already exceeded 40 mph in the Champlain Valley of VT and likely will at least exceed 30 mph for many communities by day’s end. Clouds will remain variable as milder air moves in aloft and collides with our departing cold, and this is likely to be the case overnight Wednesday night into Thursday, as well, though precipitation will remain limited to some flurries at the border with Canada Wednesday afternoon and some scattered snow showers in Northern New England on Thursday. With much less wind expected Thursday, high temperatures around 40 south and in the 30s north will actually feel much better in the absence of wind chill. All the while, the jet stream pattern across the country – the fast river of air, high in the sky, that steers disturbances and storm systems – will be aligning in a pattern that favors storminess in the eastern half of the nation. The first developing strong storm will find its footing Friday over the Gulf Stream, off the Eastern Seaboard, and move north. With a razor-sharp western edge to its precipitation shield, this storm is unlikely to deliver much more than clouds to most of New England, but we’re watching the track carefully for communities within about 30 miles of the coastline in Eastern New England, and especially Cape Cod and Eastern Maine, closest to the storm’s track and most likely of anyone to see some rain to snow or simply snow that may accumulate Friday. Although the most likely forecast is a coating to an inch or two near the coast and onto the Cape, the increase in precipitation is significant with this storm as you get closer to its center, so a slight deviation west would mean a bigger deal while a nudge east would put nearly all of us in the clear. The Friday storm moves east Friday night, but does an effective job at carrying cold, arctic air back into New England Friday night through the weekend, with Saturday high temperatures likely only in the teens south and single digits north with a biting breeze, then only about ten degrees less cold Sunday. Meanwhile, the busy jet stream pattern will already be brewing the next storm – energy dropping southeast from Canada will paint a stripe of accumulating snow from the Upper Midwest through the Tennessee River Valley, then couple with a southern disturbance chock full of Gulf of Mexico moisture to drop snow over Georgia, the Carolinas and march a strengthening, moisture-loaded storm up the East Coast Sunday night into Monday. Our team has issued a First Alert for Monday, owing to the exceptional amount of moisture and the preceding cold air that seems likely to crank out at least some accumulating snow, even if a rain/snow line were to end up over Southern New England Monday, which is still TBD hinging on storm track. Regardless, whomever is northwest of the storm track is likely to pick up plenty of snow. Winter air remains through the end of the 10-day forecast.
It’s one thing when it snows in New England – it’s another thing when the temperature in the sky aloft is absolutely perfect for accumulating snowflakes and that was the case this time around. In every snowstorm, snow crystals develop in the cloud above – different snow crystals develop depending upon the atmospheric temperature and moisture conditions in the cloud. Sometimes, “needles” or “prisms” develop: thin, narrow and small snow crystals that join together to form delicate, fine snowflakes that dance lazily down to the ground and accumulate slowly. Once in awhile, though, the atmosphere sets up just right for “dendrites:” sticky, branched snow crystals eager to coalesce and form large, quickly accumulating snowflakes that add up fast and can result in snow accumulating two to three times faster than “ordinary” snowstorms – that’s exactly what happened from Central CT to Northern RI and Eastern MA in the Boston Metro Friday. In fact, contrary to the usual ratio of one inch of precipitation (liquid) equaling ten to fifteen inches of snow, Thursday’s reports revealed a few communities were observing on the order of twenty and thirty inches of snow to one inch of liquid! This blew the forecast wide open where the perfect snow conditions sat for hours on end, including the immediate Boston Metro. With temperatures near the melting point, road treatments have led to dramatic improvement to slushy and wet conditions on Interstates with slower improvement on local roads, and with the snow tapering to little more than flurries during the middle to late afternoon (a bit later along the Maine coast), clearing the driveway will bring a lasting result and is a worthwhile proposition with a solid freeze-up expected Thursday night as lows drop into the teens, also creating slick road conditions. Saturday will be bright, but it won’t be warm – most high temperatures will be in the 20s. The cold air relaxes a bit Sunday, but the problem is a disturbance comes racing in, producing a round of morning freezing rain showers for the deep interior with some slick spots from morning to midday, snow showers to freezing rain in the mountains and mostly midday and afternoon rain showers for the Metro areas of Southern New England. This precedes a sharp shot of arctic air that arrives for Tuesday, likely to keep daytime highs in the teens south and single digits north with subzero wind chills! The upside to the biting cold is the air is relatively dry, holding off any threat of new storminess until at least the end of next week in the exclusive First Alert 10-day forecast.
Snow is on the way for Friday. After a fair and seasonable Thursday with temperatures almost exactly where they should be for early January in the 30s to near 40, clouds will increase Thursday night ahead of an approaching storm. Producing snow across the Midwest Thursday morning and set to drop accumulating snow from Tennessee to the Appalachians and Mid-Atlantic Thursday evening and night, the storm will strengthen once it hits the Atlantic waters south of New England Friday morning. Snow is set to begin for much of Southern New England after midnight through the predawn hours, arriving slightly later to the State of Maine during the morning, but dropping snow steadily through Friday morning into midday for nearly all of New England. With a north to northwest wind for most of New England, coastal flooding isn’t expected to be much of a concern except perhaps some minor midday high tide flooding Friday on Nantucket. Similarly, the wind will gust to 30 or 35 mph at times but isn’t expected to do damage. So, the most impactful part of this storm will focus on the snow – with enough cold air for a nearly all-snow event in New England, travel will be extremely difficult from the predawn Friday until the intensity wanes in the early afternoon, then shuts down entirely for most communities during the middle to late afternoon. By that point, after recording one inch per hour snowfall rates at times, most communities in Southern and Eastern New England will approach half a foot of snow with some communities south of Boston primed to receive jackpot amounts that may reach eight inches! Either side of those highest amounts, snow totals will only gradually decrease – on the Cape due to a heavy, wet consistency that may even mix with sleet and rain at times on the Outer Cape and Nantucket, and a gradual drop in snow amounts to the northwest where the snow will be fluffier due to colder air…but less moisture falls from the sky. By Friday evening, skies will start to clear and temperatures will remain well below freezing Friday evening and night, meaning lingering moisture on roads will freeze for slippery travel conditions to continue, but driveway cleanup Friday afternoon should hold just fine through the overnight. Saturday brings sunshine but chilly air with highs falling shy of 30 degrees for most of New England, then the next disturbance slides in for Sunday. With cold air ahead of it, Sunday’s disturbance should deliver snow showers to Northern New England, freezing rain showers to Central and Western New England with slick roads for some and, by the time the showers arrive to the urban areas of Southern New England Sunday late morning to midday and into the afternoon, more plain raindrops will be mixed in. Our First Alert Team is still expecting some really cold air by Tuesday of next week, but dry enough air to hold off any chance of a storm until later next week.
Friday morning snow wasn’t a lot, but it’s been enough to deliver a White Christmas to much of Connecticut, Western and Central MA, and while we may not hit the one inch snow depth technically designated to be a White Christmas in all of Rhode Island to the Boston Metro, many folks saw a dusting. That wasn’t the case from the MA/NH border and Northern Essex County points north, where some of Northern MA to Southern NH will be missing snow on the ground this year, though much of Northern New England still has snow from our previous storms. That said, the great weather news for those making the rounds to friends and family Christmas Eve is New England will be dry from Northern Maine to Southern CT, with only patches of black ice where daytime snow melted and refroze, and winds will be nearly calm for Santa’s flight. The weather will go downhill quickly in the predawn Christmas morning, however, as the next disturbance – an energetic one aloft – approaches from the west and sparks surface storm development over New England for a growing swath of precipitation from 2am west to 4 am east, continuing through the day. The problem with this setup is an abundance of cold air near the ground but an abundance of warmth and moisture aloft – a great setup for freezing rain in most of interior Southern New England. Although this doesn’t appear to be an ice storm that will knock out power to those who see Christmas morning freezing rain, travel will be significantly impacted by icy roads and the need for treatment and re-treatment for a few hours – from 4a to 9a for many, and as late as 10a to noon northwest of Boston in the upper Route 495 belt to Route 2 and Southern NH. Farther north, the weather becomes more of an issue for much of the day Christmas Day – in the northern half of New England, a combination of snow and sleet will turn to rain for some of Vermont, freezing rain for the Eastern Slopes of the Greens into Central NH, and a combination of snow, sleet and freezing rain for much of the Lakes Region to the Mountains of NH and much of Maine. At ground level, temperatures will jump either side of the freezing mark Christmas afternoon and evening, making for a very tricky storm for particularly NH and ME road treatments with multiple types of changing precipitation, so while right now our snow total forecast is 2”-4” in a large area, we believe there will probably be a bullseye of 6”-8” in the mountains, and the amount of mixed precipitation elsewhere means the limited snow accumulation forecast may serve to hide just how messy the day and evening will be, keeping road crews away from family for much of Christmas Day and catching motorists off guard at times in changing conditions. Expect most of the mix to change to snow in Northern New England Saturday night before winding down Sunday morning, with Southern New England rain shipping out very early Sunday morning, as well, for improving conditions. Next week will bring a very active jet stream to the United States, meaning multiple storms – although we may avoid the brunt of them, we’ll be keeping a close eye on a busy weather pattern.
After cold sun, blustery northwest wind with a wind chill in the teens & 20s, clouds thicken tonight, light snow arrives 11 PM at the NY border of NewEng and 3-4 AM Eastern NewEng. Cold roads, lows around 20 means even light snow sticks. Continues thru Fri AM, including Cape Cod!
After the aforementioned coating-2" for some Fri AM, sun comes out Fri PM but next disturbance arrives Christmas AM. Brief window of opportunity near/north of MA Pike for early AM snowflakes before change to light freezing rain, then stray raindrops rest of day south, snow north.
Disorganized storm over NewEng Christmas gains organization late day to night, swath of accumulating snow sets up north of storm center, namely Northern NewEng. This is total Fri-Sun snow, I think there's room to raise this forecast north & note some snow may fall Sun AM south.
Looking ahead to next week, it'll be a busy week across the country with multiple rounds of atmospheric energy ejecting into a fast jet stream from a stormy West Coast. Feet more snow will fall in some of the Rockies. New Year's Eve may bring rain and snow to the Northeast.
Red is where some light icing may occur predawn Wednesday w/freezing rain showers. That said...it's a matter of one or two degrees so I'll be shocked if literally that whole area ices, but consider yourself on guard! Worst icing farthest north. Travel impact, not power outages.
In the mountains of NH and ME to Northern ME, Wednesday will be cold enough for 1-2, 2-4 and 4-6 inches of snow. Following Wednesday's strengthening storm to our southeast that delivers our combo of snow/freezing rain/rain, winds kick up Wed evening and night, driving wind chills subzero overnight in Northern NewEng. No damaging wind expected.
But what about those Xmas Eve & Day snowflakes? A quick-moving disturbance overnight Thursday night will deliver snow showers and perhaps a coating to 1" of snow with some higher amounts in the mountains into Christmas Eve *morning* before sun comes out for the afternoon.
Christmas Day continues to look like a prolonged period of light snow and rain with the placement of the rain/snow line TBD but perhaps starting somewhere near the MA Turnpike and drifting north during the day as temps slowly climb near 40 there, 30s north.
Saturday Mix of Snow, Sleet and Rain To Cause Travel Delays For Many, Winter Storm Conditions Central & North
For the full video forecast as seen in my broadcasts on NECN today, click here.
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Very hard to believe snow will fly for many in New England tomorrow when the entire six-state region is over 40° this morning with the South Coast around 60° - but that's the expectation for many (not all) in New England Saturday.
After temperatures only very slowly ease down overnight Friday night on a continuing northwest wind that will be far lighter than today's 35 mph gusts, precipitation will move into southwestern New England around sunrise Saturday, as a mix of mostly raindrops & a few flakes in CT.
By lunch hour, snow, mix and rain will be expanding northeast. Because temperatures for many will be above freezing, roads start out melting a lot of this, but hilly terrain of Central and Western New England may start to see some greasy roads developing.
Between 2 and 4 PM, snow increases, temperatures drop a few degrees, and many communities away from the coast (particularly near, along and outside I-95) will see roads begin deteriorating. Less of an issue near coast and SE MA/RI. Sleet increasingly mixes in Central/Western MA.
The mix with and change to sleet inland rides northward into Southern NH by Saturday evening, with areas closer to the coast - inside of and in the Merrimack Valley perhaps to Rte 495 - going to rain for a time, cutting back on amounts & allowing some road improvement.
Snow amounts hinge heavily on placement & migration of rain/sleet areas that cut off or severely limit accumulation. There should be a sharp increase from a broad area of 1-2" to the 4"+ area, and though I've tried to indicate it, it may be tighter than shown here.
Biggest reasons I haven't drawn snow gradient (ramp up in amounts) as tightly as I think it'll end up being are: 1) if I get it wrong by 20 miles, I've drastically over/under prepared folks either side of the line; 2) with such tight difference, small shift may require adjustment.
The introduction of sleet has me fairly confident on the Worcester County part of this forecast, I think the more malleable part is Eastern Middlesex to Essex and Southeast Rockingham Counties where snow, sleet and coastal rain push all come into play.
Farther west in New England, any change to rain seems quite unlikely for many - sleet will be the much bigger contributor to limiting snow accumulation the farther south one is. Keep in mind sleet still poses travel issues.
Northern New England is more clear-cut: a snow event with perhaps some sleet mixing in for some of Southern VT, Central NH and maybe Southern ME, but mostly a wintry, snow event. Great news for skiers and snowmobilers, though the Crown of Maine more removed from moisture.
One to three inches of mountain snow tonight ushers in 60° weather for some Thursday...then accumulating snow returns for some of New England Saturday, with a First Alert for Northern New England, watching rain/snow line farther south. Christmas Eve was on the AM 10-day!
After a dry Wednesday, rain and snow showers arrive from west to east in New England, early evening (west) to late evening (east). Mostly rain southern half of New England, snowy roads in the accumulating snow area. After early AM showers Thursday depart for all but far northern Maine, temperatures will rise as a southwest wind increases. Little additional rainfall is expected aside from a wandering sprinkle/light shower Thursday, with a break or 2 of PM sun possible. Gusty, not damaging.
Here's our latest NBC Forecast System snow prediction for Saturday's storm. Remember: the storm is nearly guaranteed to happen, we've had 95-100% chance of precipitation last couple of days. Big question is where does rain/snow line set up . Interestingly, both the operational American (GFS) and European (ECMWF) guidance indicated the potential of a sizeable snow event Saturday as far south as the MA Turnpike corridor. I'm certainly not arrogant enough to write that off, I just find it hard to believe in this setup. Our forecast high temp Friday is 55-60° in Southern New England so you need to drive in new cold by Sat mid/late AM when storm arrives - we can do that with a dropping dew point (meaning air can cool as storm moves in) in Northern NewEng, just not sure we can do it south. The north wind Friday night into Saturday at this point is forecast to be fairly light, not screaming in, so it's a cold air drain that will reach a peak Sat AM, then turn around as the wind turns to blow from the east and southeast later Saturday. All these factors together tell me chance of accumulating snow Northern half of New England is quite high, with Southern NH/Northern MA southward much less certain on how much snow - if I were a betting man, I'd lean wet not white there. But, humble approach, will keep watch.
So, there's the issue of the disappearing storm next Tue (photo 1: yesterday's Tue forecast, 2: today's), I don't entirely trust that. 1st, this goes down as one of the most *rapid* changes from storm to no storm in my recent memory. How does such major change happen? The difference is evident not only at the surface, but also hugely apparent in the middle/upper levels of the atmosphere. Check out the atmospheric energy (vorticity) forecast valid next Tuesday from yesterday, then from today. Note the huge missing energy over the Northeast. This kind of total disappearance is rather incredible - we often see changes in position or timing, which can impact larger things like whether two or more disturbances "phase," but the total liquidation of a disturbance in 12-24 hours is rare. The key to the major change in the forecast is this: if you follow the instigating, southern lobe of energy that was supposed to create Tuesday's storm backwards, you find it has just emerged over the Western Pacific. I've circled it in red. This is a data-sparse area. "Initialization" is a huge component of numerical weather prediction (computer guidance) - if you could initialize everything perfectly, you'd have perfect forecasts. Reality is a lot happens between the sparse measurements we can take of our atmosphere at any given time. Initialization incorporates multiple methods of estimating what's currently happening in the atmosphere: weather balloons, airplane information and (hugely) satellite estimation are biggest components. In the current position of the disturbance in question, little of any of those. This sets up an interesting situation where you have a disturbance poorly initialized that was supposed to be a big player. You have to at least consider the possibility that, when sampled more adequately, its impact may suddenly "reappear." For this reason, even though even our NBC10 Boston/NECN Forecast System shows less than a 10% chance of precipitation on Tuesday now, you're still seeing some snowflakes in the forecast for Tuesday. Not ready to let go of it until this thing comes a bit farther east.
Our 10-day forecast on NBC10 Boston and NECN features a few major points: 60° Thu and 2 storm chances, Saturday & again Monday night through Tuesday. Thursday's warmth is heralded in by Wednesday night snow to rain showers in Northern New England, rain showers south...all of which ends early Thu for more clouds than sun, a strengthening but non-damaging southwest wind and temps reaching around 60° south and 50° north. This weekend begins an active pattern of weather, at least aloft. The jet stream - the fast corridor of wind that steers storms and separates cold to the north from warm to the south - comes almost right overhead. First storm potential comes Saturday. Overall I'm unimpressed w/ Saturday's system. Fast moving & coming through a very fast, flat flow that rarely allows for significant development. Additionally, Fri will be 40s/50s so air is dry, not cold, meaning Southern New England will lean rain, best chance few inches snow North. There are some meteorologically more favorable conditions for snow in the Mon Night/Tue system than Saturday, if the storm does, indeed, evolve. 1) The preceding storm Saturday deepens east of Newfoundland, deepening the jet stream trough south of Greenland...2) The deepening of the jet stream trough south of Greenland affords some jet stream ridging (a rise northward) near Nova Scotia, which brings some "amplitude" or a tendency for jet stream waves favorable of storm strengthening and this storm enters that favorable zone. 3) The cold air preceding the storm is in place much more firmly than the Saturday system. Highs Monday are only expected to reach the upper 30s with dew points low enough to allow for more cooling Monday night/Tue when precipitation would move in. 4) Due to favorability for "waviness" in the jet stream (meteorology-minded: shortwave ridging over Nova Scotia allows for a digging/amplifying shortwave trough near New England), energy is more neatly bundled & has opportunity to move south of New England, increasing chance of holding cold. All of these factors, IMHO, make Mon night/Tue best opportunity for accumulating snow in the next 10 days in what has been very limited opportunities. Clearly 45% chance from NBCU Forecast System isn't a lock, but 30%+ from our system is a good signal, so will keep watch.
Mild air the talk of Saturday in Southern New England, but mild air will have a very hard time scouring out AM cold in some of Central/Northern New England, meaning freezing rain for many in the morning. Planning on driving to these areas? If you have flexibility, leave this eve! Closer look at Northern and Central New England areas I expect to be icy Saturday morning...worth noting those really light areas into North-Central MA probably, in reality, will be very isolated/uncommon vs. widespread areas farther north. Significant travel impact pink areas. Once the mild air takes hold...which happens early with mild morning to midday showers south and waits until later north...isolated damaging south-southwest winds will kick up (more south-southeast component North Country), especially evening to night. After morning to midday showers for many, there will be a relative lull in the showers for the afternoon to early evening - a few showers may still meander through, but not nearly as many. Temps will be in the 60s south/50s north as wind ramps up during that 2nd half of the day. Exclusive NBC10 Boston & NECN 10-day forecast gives little hope to those dreaming of a White Christmas. HOWEVER...take a look at Day 10. I mentioned on the AM news on both stations a colder pattern takes hold the week of the 20th. Starting from behind, but not entirely hopeless.