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.

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.

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.

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.

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.

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.

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.

March is supposed to come in like a lion and go out like a lamb, or so the old saying goes. Well, it certainly came in like a lion, but now it’s also going to go out like a lion too. Don’t worry, a repeat of the April Fool’s Blizzard in 1997 is not coming, but we do have some snow to worry about across parts of the region.

The storm that we’ll have to contend with Friday into Saturday is moving into the Midwest today, with plenty of severe weather expected ahead of it. This system has already produced a lot of severe weather from the Southern Plains and Texas into the Mississippi Valley over the past couple of days. Don’t worry, we won’t have to contend with severe weather up here. As the storm heads into the Midwest, it will eventually redevelop off the Mid-Atlantic coastline and pass south of New England late Friday into Saturday. Meanwhile, high pressure will move into eastern Canada, keeping some marginally cold air in place, setting the stage for a return of wintry weather to New England.

We’ll have some snow or rain showers developing Friday morning, but with temperatures in the 30s to lower 40s, we won’t see much, if any, accumulation during the daytime. The sun angle is getting relatively high, so even with the cloud cover, it still is strong enough to prevent much accumulation, at least on paved surfaces.

After the sun sets, things get a lot more complicated. Without the sun, and with temperatures dropping into the lower to middle 30s, along with the heaviest precipitation moving in, we’re looking at a changeover to snow for most places, especially away from the coastline. The problem is, some warmer air looks like it will move in aloft for a while. With a warm layer aloft, the snow that’s falling melts, then starts to refreeze as it moves back into the colder air below that layer. The result is sleet, and possibly a lot of it well inland. This will significantly cut back on snowfall accumulations.

Once we get into Saturday morning, a change to rain is likely for much of the region, but even where it stays mostly snow, we won’t have much additional accumulation, at least on paved surfaces.  A few showers may linger into Sunday as an upper-level storm system moves across the region, then high pressure brings sunshine and seasonably cool temperatures in for Opening Day at Fenway on Monday.

So, how much snow are we looking at? We’ve bumped up amounts a little since yesterday, but nothing significant:

South of the Mass Pike: A coating at most.
Metro Boston: 1-2″
128 Belt: 2-4″
Merrimack Valley: 3-5″
NH Seacoast/North Shore: 3-6″
Southern NH: 4-7″
Worcester Hills/Monadnocks: 5-10″

Before you ask, no, this is probably not the last time we’ll see snowflakes this season. It may be the last “snowstorm”, but even that’s not a definite. Remember, we’ve had snowstorms around here into late April and early May before.

It’s time for March Madness once again, and we’re not talking about the NCAA Basketball Tournament. No, this time we’re talking about the relentless hype ahead of a March snowstorm. You’d think that we’ve never had a big storm around here in March before with the way the media is reacting. It’s almost as if everyone has forgotten about the storms in 1993, 1997, 2007, and 2013, never mind the ones we’ve had in April (or May).

Well, enough about that, let’s get right to the details of the storm. Low pressure is moving across the Ohio Valley today while a second area of low pressure is starting to develop off the Southeast coast. As the Ohio Valley system weakens tonight, it will transfer its energy to the coastal storm, and then the fun really begins.

The low will move up the coastline tonight into Tuesday and rapidly strengthen. Snow will break out across the region around daybreak Tuesday, and will fall heavy at times from mid-morning into the evening. Snowfall rates of 1-3 inches per hour seem likely. The snow will be accompanied by winds gusting to 40-50 mph at times, even higher near the coast, and especially across Cape Cod. This may create blizzard conditions at times, with significant blowing and drifting snow expected. We’d recommend that you stay off the roads, as travel will be dangerous at best during the daytime hours. The good news is that the storm will be moving relatively quickly, so the snow will taper off in the evening, and end at night.

The big wildcard at this point is the exact track of the storm. Some of the models are trying to indicate that the storm will move across southeastern Massachusetts late in the day, while others keep the storm near or just east of Cape Cod. The farther the storm tracks to the west, the more likely a change to sleet and/or rain becomes across southeastern Mass, possibly as far inland as the I-95 corridor. Obviously, that will have a big impact on snowfall totals.

So, how much snow are we looking at? Well, many in the media have been throwing out amounts like 1-2 feet or some other ridiculous numbers. The fact is, with a storm moving as quickly as this one is (it’s only going to snow for about 12-15 hours), it’s tough to get amounts that high. Our forecast is as follows:

Cape Cod: 3-6″ on the Outer Cape and Islands, 5-10″ closer to the Canal

SE Mass/RI: 6-10″ from I-95 south and eastward, 10-16″ north and west of there.

The remainder of Central & Eastern Mass/N RI/Southern NH/southern ME: 12-18″, with isolated heavier amounts.

Even though the snow will be winding down Tuesday night, Wednesday won’t be a great day for cleanup. With an upper-level low moving across the region, and the storm itself getting cranked up in Atlantic Canada, it’ll be cloudy, windy, and cold, with scattered snow showers. While there shouldn’t be much additional accumulation. Another inch or two is possible in a few spots.