Weekly Outlook: December 25, 2017 – January 1, 2018

Yup, you read that headline right – 2018. We’ve entered the final week of 2017. Once we get through our Christmas storm, things are fairly simple (and fairly cold) for a few days. The end of the week and the weekend? That’s another story altogether.

The week starts off with a storm bringing some light to moderate snow to areas north and west of Boston, with rain possibly ending as some wet snow from Boston southward. Our thinking really hasn’t changed much since our blog post on Saturday, and by the time most of you read this the storm will be nearly or completely done, so we won’t waste too much time on it. As the storm moves into the Gulf of Maine, it will rapidly intensify, bringing strong winds to the area during the afternoon. While we’ll still have gusty winds for a few more days, they won’t be anywhere near as strong as we’re expecting today.

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ECMWF forecast for low temperatures Thursday morning. Yeah, that’s chilly. Image provided by Weather.us

A weak upper-level disturbance moves through on Tuesday, but it’ll just produce some clouds and maybe a stray flurry or two, but the bulk of any snow shower activity will be confined to Northern New England. After that, high pressure builds in with dry and cold conditions. In fact, low temperatures will likely drop below zero for many of us either Wednesday or Thursday morning.

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This is how the model forecasts look beyond 3 days at this time. In other words – anyone who tries to give you a forecast with any certainty beyond 3 days has no idea what they are talking about.

 

After Thursday? Well, there really are no definitive answers at this point. The forecast models are all over their place and their performance beyond 3 days lately could accurately be described as “flaming garbage.”  To give you an idea, here’s what the most recent run of some models show for the Friday through Monday period:

Model 1: A light to moderate snowstorm Friday night into Saturday and a moderate to heavy snowstorm Monday night into Tuesday.

Model 1 Ensemble Mean: A light snowstorm Friday night into Saturday, then high pressure builds in.

Model 2: A moderate to heavy snowstorm Saturday night into Sunday.

Model 2 Ensemble Mean: A light to moderate snowstorm on Saturday.

Model 3:  High pressure in control with no appreciable precipitation.

Model 3 Ensemble Mean: A light to moderate snowstorm Friday night into Saturday, then high pressure builds in.

As you can see, we’ve got many conflicting possibilities from just 3 models and their ensembles, so how are we supposed to make any sense from that? So, if you hear someone tell you that we’re getting a snowstorm on a certain day next weekend, don’t believe it. At least not yet. That is a low confidence forecast at best.

Monday: Snow ending by midday north and west of Boston, rain possibly changing to snow before ending around midday from Boston southward. Becoming windy in the afternoon with some clearing possible. High 30-37, except 38-45 across southeastern Massachusetts in the morning.

Monday night: Clearing and breezy. Low 15-22.

Tuesday: Sunshine and some afternoon clouds, slight chance for a flurry, continued breezy. High 21-28.

Tuesday night: Clear and cold. Low -3 to +7 north and west of Boston. 8-15 above from Boston southward.

Wednesday: Plenty of sunshine, breezy, and cold. High 14-21.

Thursday: Mostly sunny and frigid. High 8-15.

Friday through New Year’s Day: Some unsettled weather is possible, but as we mentioned above, trying to pinpoint any details, including which day, just can’t be done yet. Temperatures will remain below normal.

 

Bing’s Dream Will Be Reality for Most of Us.

We’ve all heard the opening line of the song more times than we can remember:

“I’m dreaming of a white Christmas, just like the ones I used to know”

Well, this year, it won’t be a dream for a large portion of the region, it’ll be reality. Across southeastern parts of New England, mainly south and east of I-95, – sorry, it’ll be a green Christmas for you, with mostly rain from the system.

Christmas Eve will actually be a fairly nice December day by New England standards. We’ll start the day with some sunshine, but clouds will move in during the afternoon as low pressure moves into the eastern Great Lakes. High temperatures will reach the upper 30s to lower 40s, which is right around normal for late December.

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The NAM model shows the progression of the system with the secondary area of low pressure developing off the New Jersey coast and crossing the Outer Cape. Loop provided by Pivotal Weather.

As we head into Sunday night, right around the time Santa is making his rounds, snow will break out across the region, with rain across southeastern Massachusetts and parts of Rhode Island. At the same time, a secondary area of low pressure will start to take shape off the Mid-Atlantic coastline. This low will start to head northeastward, likely passing very close to, or perhaps right over, the Outer Cape, on Christmas morning. As a result of this track, the rain/snow line will likely penetrate as far inland as a Boston-Providence line. Obviously, any variation in track will impact how far inland that warmer air penetrates, which will impact the snowfall forecast. The snow will come down at a steady pace for much of Christmas morning, tapering off and ending by midday as the storm moves into the Gulf of Maine, where it will really get cranked up (more on that in a moment).

So, how much are we looking at?

If you live south and east of a line that runs from Boston to Providence (roughly Interstate 95), probably just a brief dusting at the tail end of the storm as colder air comes back in as the precipitation is ending.

If you live just west of I-95, from Northern Rhode Island into the Boston area and Metro West, 1-3 inches.

Anywhere outside of there, especially the I-495 belt from Central Massachusetts into the Merrimack Valley, North Shore, Southern New Hampshire, and the New Hampshire Seacoast, 3-6 inches, with some isolated spots picking up as much as 8 inches.

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The ECMWF is closest to our thinking for snowfall with the Christmas storm system. Image provided by Weather.us

 

As the system moves into the Gulf of Maine Monday night into Tuesday, gusty winds are likely behind it, ushering much colder air into the region. Low temperatures Tuesday morning will drop into the middle teens to lower 20s, but wind chills will be in the single numbers and even below zero in spots Tuesday morning. This is also bad news for places that had mainly rain during the day, as it will ice everything up in the evening, creating some slippery travel. This bitterly cold air looks to remain in place for much of the week as a large area of high pressure builds in. We’ll get into more detail in our Weekly Outlook Monday morning, but this high pressure area is good news, as it may help to deflect a potential storm later in the week off to our south (much to the chagrin of the Facebook Forecasters who were already trumpeting about a potential snowstorm a week in advance because some of the models showed it).

Big Changes for Friday/Saturday

In our Weekly Outlook this past Monday, we talked about a storm heading into the Great Lakes this weekend, with a warm front bringing rain and mild conditions on Saturday, but Friday would be cool as the warm front struggled to cross our area. Well, things have changed considerably, and not for the better.

Low pressure will still move into the Great Lakes Friday/Saturday, and a warm front will get hung up to our south. The problem is, that warm front may not make it any farther north than the South Coast. Even worse, we’re looking at precipitation streaming in on Friday, continuing more or less into Saturday afternoon. Cold air in place, precipitation moving in, warmer air eventually moving in aloft. If you’ve lived around here long enough, you that means we’re looking at a snow to freezing rain situation.

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Freezing rain could be a significant problem from northern Connecticut into central/western Massachusetts and southern New Hampshire Friday into Saturday. Image provided by WeatherBell.

 

Snow should develop across southern New Hampshire and northern Massachusetts around midday Friday, with a mix of snow, sleet and freezing rain moving into the Boston area during the afternoon, and rain, possibly mixed with a little snow south of Boston by late in the day. Eventually, a change to freezing rain will take place north and west of Boston Friday night as warmer air moves in aloft. The problem is, that cold air at the surface will be pretty tough to dislodge. Temperatures will slowly drift up, likely getting above freezing by Saturday morning inside Route 495. However, from the Merrimack Valley into southern New Hampshire, there is the chance that temperatures never reach 32, or if they do, it won’t be until late in the day, after most of the precipitation has fallen.

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The GFS is only forecasting high temperatures in the middle 30s from Boston northward and westward on Saturday. That may even be too optimistic. Image provided by WeatherBell.

 

Before the change to freezing rain, we are looking at some snow accumulation, mainly north and west of Boston. As much as 1-3″ could fall in the Merrimack Valley, with 3-5″ from the Seacoast over into southern New Hampshire. If the changeover takes even longer than we currently expect, then these totals could end up higher.

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A few inches of snow is expected before the change to freezing rain late Friday into Saturday. The best chance for significant snow (6″+) would be in southern and central NH. Image provided by Weather.us

 

As for the potential for a White Christmas – we told you on Monday that the odds were low, but not zero, despite what some of the folks on TV were saying. Well, those odds have raised significantly. After a cold front moves through here late Saturday, it will stall offshore. Another wave of low pressure will ride along it on Christmas Day. Exactly where that front stalls is obviously key to the forecast. There’s still a large range in what the models are showing – anything from just a few flurries to heavy snow inland with rain along the coast, but it certainly seems like we’re in for *something* on Christmas Day. We’ll take a look at that in more detail once we get past the Friday/Saturday storm. Oh, and if you hear any hype for another storm next week – yes, the models are showing something, but it’s still over a week away. We don’t have to tell you that the forecasts can and will change several times before then, because you already knew that. Remember, it was just 2 days ago that we were talking about highs in the 50s on Saturday, not an ice storm.

 

Weekly Outlook: December 18-25, 2017

We’ve reached the week before Christmas, and the first day of astronomical winter is this week as well, so 2017 is nearly done. Winter officially starts at 11:28am on Thursday, but next weekend, it’s probably not going to feel like winter around here. That doesn’t mean we’re not going to have a White Christmas however.

The week starts off with a weak storm system impacting the region. It’s not going to have a lot of precipitation with it, but temperatures will be fairly close to freezing, so the morning commute could be impacted. Right now, it looks like some light snow, mainly less than an inch, could impact areas north and west of Boston for the Monday morning commute. Elsewhere, we’re looking at a little bit of rain. Occasional rain or snow showers are possible during the day, with some freezing drizzle possible, especially across the 495 belt and into southern New Hampshire. So, if you have to drive in these areas during the day, make sure you pay attention to the road conditions and drive carefully.

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While precipitation will be mostly rain from Boston southward on Monday, some freezing rain is possible from northeastern Massachusetts into southern New Hampshire. Image provided by WeatherBell.

By Tuesday, we’ll actually turn a bit milder before a cold front crosses the region. That front may bring in a few showers later on Tuesday, then colder air settles in behind the front for Wednesday and Thursday on gusty northwest winds. By Friday, a warm front will approach the region ahead of low pressure moving into the Great Lakes. The warm front may take its time moving through, so temperatures may stay on the cool side, especially north and west of Boston, but the warmer air should finally get in here by Saturday morning, along with some rain. In fact, Saturday afternoon could be quite mild. As the storm passes to our north and west, it drags a cold front across the area, with more seasonable conditions for Christmas Eve.

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If you believe the GFS model, you might not need a coat for that last-minute Christmas shopping next Saturday (but you will need an umbrella). Image provided by Weather.us

So, right now, you’re thinking, it’s going to be warm and raining on Saturday, how could we have a White Christmas? Some of the models show another system impacting the region on Christmas Day. However, the models disagree on many of the details. Since it’s still a week away, pinning down any of these details is next to impossible right now, but there are some models that do show some snow for at least parts of the area. Of course, there are other models that have it warm and wet again. So, there’s still a chance for a White Christmas for some of you. We don’t think it’s a good chance, but it’s certainly not zero, especially north and west of Boston.

Monday: Cloudy with some light snow or freezing drizzle north and west of Route 128, a few rain showers elsewhere. High 30-37, perhaps a little warmer in southeastern Massachusetts.

Monday night: Any lingering precipitation ends in the evening, then skies remain partly to mostly cloudy overnight. Low 27-34.

Tuesday: Plenty of clouds with a few showers possible. Becoming windy. High 41-48.

Tuesday night: Clearing, windy. Low 28-35.

Wednesday: A mix of sun and clouds, breezy. High 33-40.

Thursday: Mostly sunny and cold. High 27-34.

Friday: Becoming cloudy and breezy. High 30-37. Temperatures likely rise at night.

Saturday: Windy with rain likely in the morning, tapering off in the afternoon. High 49-56.

Christmas Eve: Partly sunny. High 41-48.

Christmas Day:  Mostly cloudy with a chance of snow or rain. High 35-42.

Weekly Outlook: December 11-17, 2017

You survived the first snow event of the season. Granted, it wasn’t a big storm, but still, you cleaned your car, maybe you even shoveled your driveway. It’s done. It’s over. Feel better? Good, there’s more on the way.

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Sure we had some snow on Saturday, but at least you weren’t in Buffalo on Sunday for the Bills and Colts game. Watching those two teams is bad enough, but in heavy lake-effect snow? No thanks. Image provided by The Buffalo News.

The week starts off with a weak disturbance moving through during the morning, which may produce a few snow showers. So, if you wake up and there’s a dusting on your car, that’s why. High pressure then briefly builds in with clearing and cool conditions for the rest of the day. Clouds quickly come back Monday night as an Alberta Clipper heads towards the region. It will pass north of us on Tuesday. That’s good news for many of you. Although we’ll see some snow develop during the morning, with the storm passing to our north, warmer air moves in, changing the snow quickly over to rain along the coastal plain. Farther inland, especially north and west of I-495, the changeover will take longer, but even there, it should take place during the afternoon, but not before we see some snowfall accumulations. How much accumulation? Right now, it looks like an inch or less in the Merrimack Valley, and 1-3 inches from the Seacoast into the Manchester/Nashua area. North of Manchester, especially up towards Concord and points north and west, we could be looking at 3-6 inches or more.

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Snow may start during the morning commute on Tuesday, but the evening commute should be wet, not white. Loop provided by Pivotal Weather.

Once that system passes by, some of the coldest air so far this season flows in for Wednesday and Thursday. Gusty west to northwest winds will send wind chills into the single numbers and teens. Yeah, it’s gonna be chilly. At least the sun will be out, not that it’s going to help much.

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Planning to take that morning run on Thursday? Better layer up, because wind chills will be in the single numbers and teens. Image provided by WeatherBell.

Friday is the interesting day this week. A storm system is going to develop and pass offshore south and east of the region. The question is, how far to the south and east. Right now, the models bring the storm close enough for a period of light snow across southeastern Massachusetts and southern Rhode Island. Knowing how these models work and their normal biases and corrections, we have a hunch the storm will end up closer to the coastline, thus spreading snow farther inland. We’re not expecting a blockbuster storm here, but some light to possibly moderate snow is possible on Friday. We’ll obviously keep an eye on this during the week, and if the threat does materialize, we’ll update you. High pressure builds in behind that system with cool and dry conditions next weekend.

Monday: Chance for a morning snow shower, then becoming partly sunny. High 32-39.

Monday night: Clouding back up with some snow possible towards daybreak. Low 20-27.

Tuesday: Snow developing, quickly changing to rain across much of the region, except taking a bit longer north and west of I-495, where some accumulations are possible. High 35-42 north and west of I-495, 43-50 elsewhere.

Tuesday night: Rain ends in the evening, followed by clearing and windy conditions. Low 19-26.

Wednesday: A mix of sun and clouds, windy, and colder. High 23-30.

Thursday: Mostly sunny, still windy. High 23-30.

Friday: Becoming cloudy with a chance of snow, especially from Boston southward. High 27-34.

Saturday: A mix of sun and clouds, breezy.  High 30-37.

Sunday: Partly sunny. High 38-45.

It’s Here – The First Accumulating Snow of the Season

You can’t put it off any longer. We warned you on Monday that it was coming. The inevitable has arrived. Our first measurable snowfall of the season is knocking on the door. For those of you that hate snow – we apologize in advance.

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GFS model forecast for the progression of our system on Saturday. Image provided by Pivotal Weather.

It’s our first storm of the winter, and it shouldn’t be a big deal. The good news is, it’s going to happen over the weekend, which will minimize problems on the road. The number of people around here that can’t drive properly to begin with is already fairly high, and when you add precipitation into the mix, that number increases. Add in wintry precipitation, and the number increases even more. So, to have most of the snow fall during a Saturday evening/night will keep the number of people on the roads to a minimum.

The front that moved through here a few days ago, bringing an end to our mild weather, stalled out offshore. A wave of low pressure will ride along it this weekend, strengthening as it moves over the Atlantic south and east of the region. This is fairly typical, and how we get a lot of our snow events in the winter. It should spread precipitation into the South Coast by daybreak Saturday, spreading northward across our area during Saturday morning and early afternoon. Snow will quickly change to rain across Cape Cod, with a change to rain also expected right along the eastern coast and across parts of southeastern Massachusetts. Water temperatures are still well into the 40s, so any wind blowing off the water will bring milder air into coastal areas. Winds won’t be that strong, and they’ll be more northerly than northeasterly, which will likely prevent the warmer air from penetrating too far inland. As winds shift into the northwest behind the storm early Sunday morning, this will likely change the rain back to snow, even at the coast and across much of the Cape.

So, how much are we looking at? The map below is a close approximation, but we’ll break down a bit farther:

Cape Cod: Little to no accumulation.
Coastal SE Mass/Cape Ann: 1″ or so, maybe 2″
Interior SE Mass/Providence/Boston/North Shore/Seacoast: 2-4″
Much of the rest of Eastern Mass/Southern NH/Northern RI: 3-6″

We do think a few places could see 7 or even 8″ of accumulation, with the best chance of that happening from the hills in NW Rhode Island into Worcester County and possibly parts of the Merrimack Valley.

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Snowfall forecast from the GFS model. This closely matches our thinking for how much snow is expected. Image provided by WeatherBell.

 

 

Even though the snow will start by midday, it might not stick to pavements right away. Ground temperatures are getting colder, but pavements are a bit warmer, and having cars on the roads will keep the temperatures up a bit due to the friction. Once some steadier snow moves in, that won’t matter as much. So, if you’re heading out Saturday afternoon or evening, especially north and west of Boston, be careful. Hopefully, road crews will be ready for this, since it is the first storm of the season.

Once this system goes by, we’ll turn our attention to the next one on Tuesday. There’s still plenty of disagreements among the models on that one, so we’ll get into more detail in our Monday morning Outlook.

Weekly Outlook: December 4-10, 2017

Snow. There, we said it. We know that a lot of you hate that word. However, this is New England, it’s inevitable in the winter. The last time that most of us saw any snow around here was on April Fool’s Day. You’ve had 8+ months without it. Guess what? We’ve got some #FlakeNews for you. There’s snow in the forecast this week.

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No, it’s not going to be this bad……this time. However, winter is just getting started. You’ve been warned.

 

The week will actually start off with high pressure in control. That means dry and seasonably cool conditions for Monday. By Tuesday, the high will slide off to the east and a strong storm system will move across the Great Lakes. Ahead of it, we’ll have gusty southwest winds ushering some mild air into the region. Tuesday will likely see highs in the 50s across much of the area. With the mild air comes some rain though, mainly late Tuesday into early Wednesday. Some of the rain Tuesday night could be locally heavy. A cold front moves through Wednesday morning, with the rain ending by midday. Whatever the temperature is when you wake up on Wednesday is likely the warmest it will be all day. Behind the front, temperatures will drop during the afternoon. Thursday is the transition day. High pressure tries to build in, but a weak upper-level disturbance will pass to the north. For the most part, the day will be dry, with temperatures close to where they should be in early December.

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GFS Temperature forecast for 1am Wednesday. It’s going to be unseasonably mild Tuesday night, with temperatures likely staying in the 50s all night long, despite the rain. Image provided by Weather.us

This brings us to Friday and the weekend. We’re going to have back-to-back storms to contend with, one Friday into early Saturday, and one Saturday night into Sunday. Right now, neither storm looks like it will be a big deal, but there are plenty of questions that need to be answered as well. First and foremost – what track will these storms take? There’s lots of disagreement between the models at this point. Some models keep the Friday system too far offshore to have much of an impact on us. Some bring it closer and give us a decent amount of precipitation Friday night. The same things can be said about the potential Sunday system as well. These are things that we can’t answer yet, as there are too many things that have to happen first before we have a better idea. One thing we can tell you is that with either system, we are likely looking at precipitation falling in the form of snow across the interior. Closer to the coast, some snow is possible, but more likely, the bulk of the precipitation would fall as rain. With water temperatures still in the 40s, any wind off the water will allow temperatures to moderate quickly, making rain more likely. As for how much snow might fall – again, that is highly dependent on the storm track. A track well offshore with either storm could mean virtually no precipitation at all, thus no snowfall. A track closer to the coast could mean that you need to find your shovels and make sure the snowblower is gassed up and the plow is back on the pickup. We don’t expect significant snowfall around here no matter what the track is, but we’ll keep you informed later in the week, when we have a better idea as to what might happen. Behind that, even colder air will settle into the region next week. Yup, winter is coming alright.

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Temperature will be well below normal across the eastern half of the nation for much of next week. Image provided by WeatherBell.

 

Monday: Plenty of sunshine. High 41-48.

Monday night: Becoming mostly cloudy. Low 31-38.

Tuesday: Cloudy and becoming breezy with showers developing in the afternoon. High 48-55.

Tuesday night: Windy and mild with periods of rain. Temperatures hold steady or rise a bit overnight.

Wednesday: Showers ending in the morning, some clearing possible in the afternoon. High 52-59 at daybreak, dropping into the 40s in the afternoon.

Thursday: A mix of sunshine and clouds. High 38-45.

Friday: Mostly cloudy, chance for snow developing late in the day, changing to rain across Cape Cod and along the immediate coast. High 34-41.

Saturday: Any rain or snow ends early, then becoming partly sunny. High 33-40.

Sunday: Mostly cloudy with a chance for rain or snow, especially along the coast. High 33-40.