Monthly Archives: December 2013

New Year storm Tuesday night update

Quick update on the storm to come. It’s trended a bit south on the models. There is a lot of discrepancy. I’d say the 5%-95% confidence interval for the storm right now is 0″ to 24″. In other words, it could go out to sea and just be really cold, or it could really phase and wind up and dump two feet of powder over much of New England. Right now, I’d lean towards the middle, a good 6-12″ of snow focused mostly on Southern and south-central New England. Vermont and the Dacks will mostly get hosed, but at least nothing looks to melt for the next couple of weeks. (If the latest run of the GFS verifies—and of course one run is a single point in time—Boston will see two feet of snow in the next two weeks and temperatures that won’t top out above 35. This would be great, but probably won’t come to pass.)

Early 2014 storm

Before we look ahead to the new year, let’s review the most recent storm. The day after Christmas, I wrote:

Right now, most of Massachusetts would see rain, southern sections of Northern New England would see a mix, and Greens and Whites would see a nice snowstorm, tapering off further north.

And here’s what the snowfall map from the storm looked like:

sf1_today

 

Not a bad prediction three days out. What this means is that the rich get richer—almost all of Maine has at least a foot of snow on the ground—while the Greens, southwest New Hampshire and north of the Whites, and much of New York have paltry snow cover. Before the most recent storm, there was almost no snow north of Franconia, while Jackson had quite enough to ski. So for this coming week (New Years), the best bets look like anywhere along a line from Hanover to Waterville Valley to Jackson and anywhere in to Maine.

Now, beyond then, things get interesting. It will be cold, and a storm will make its way out of the plains and redevelop off the coast. It’s several days out, but it looks like there might be a broad foot of snow from the coast to the mountains. We could all use that as a nice surprise to ring in 2014.

Sunday’s storm: threading the needle

The bit of snow falling today should freshen up the trails in much of New England where enough of a base survived. Then it gets cooler for a couple of days, and then some warm air pushes in to New England ahead of a very cold arctic airmass. As the arctic air presses towards New England, a storm will churn northwards along the Atlantic Coast. This storm has shown more potential in recent model runs, and exactly how it interacts with the Arctic Air will be the difference between the edge of the storm, a heavy, wet, base-building snow, and a rainy mess.

It will be a close call.

Recent models have come in to a bit more consensus of a latitude-driven storm. Right now, most of Massachusetts would see rain, southern sections of Northern New England would see a mix, and Greens and Whites would see a nice snowstorm, tapering off further north. But we’ll have to watch changes in timing and track here. If the track goes further north or south, so will the rain/snow/dry areas (this looks to be a more compact storm, not one that will paste a foot of snow from Buffalo to Boston). With the approaching front, a slight change in timing and phasing will result in a dramatic difference in the amount of cold air available for the storm.

Either way, this will be one worth watching.

A little here, a little there

After the melt-pocalypse (and frankly, when will the weather channel start naming meltdowns? I’d almost allow that if we could refer “Thaw Bertha” of ’13) we’re left with some base across New England, but not really enough to ski on. The nice thing about keeping a small base, especially a bomb-proof one like you get when you dump a bunch of freezing rain on snow, is that with only a couple inches of snow you can turn it back in to excellent conditions.

And that may be about to happen. A weak clipper system is coming across the country in the next 24 to 48 hours. Such systems are often crapshoots; they can produce a few stray flurries or half a foot of powder; the storm last week morphed from a weakling in to a traffic-hell monster of powder over the course of about two days. And that may happen again tomorrow. A weakening area of low pressure will transfer energy towards the coast, and, if the NAM has it right (and it’s in the NAM’s sights) it would suddenly go from a coating of snow to a solid 2-6 inches. That amount of snow would turn the upcoming weekend from some icy skittering in to some pretty gosh-darned good conditions. It’s not the kind of base-building nor’easter we’d like to see, but we’ll take what we can get.

Most favored in this sort of scenario is the eastern half of New England. Windblown might get enough snow to start grooming on top their base again, as might coastal locations in New Hampshire and Maine. A question is whether the snow shield extends northwards from there, especially towards the eastern slopes of the White Mountains. Expect these sorts of details to be sorted out in the next few model runs.

A turn for the better

For about a week, we eked out one of the best weeks of December skiing in a while. Why was eked? Because the major teleconnections were dead-against us, and we still had a foot or two of good snow.

Of course, since then, we’ve had this bear of a system throwing up warm air and freezing rain over the entirety of the area. But as recently posted, this was not a complete disaster, as some of New Hampshire and Maine saw their snow preserved. There were some bizarre temperature swings going on in the past few days. For most of Sunday, Mount Washington’s summit was warmer than Logan Airport. As the cold air drained slowly southeast, there was a time when areas in Worcester County were 25 degrees warmer than Boston. Some stations saw their temperature drop by 25 degrees midday (OWD, for example); some fell by 20 degrees in fifteen minutes. Meanwhile at 3000 feet, it was in the 60s. Summertime!

In any case, it looks to get cold. At issue is that it looks to get cold and dry. There are some indications that we might get a bit of a surprise storm around New Year’s (a la last Tuesday), but that’s up for grabs. So, cold is good, now can we get some help from the teleconnections?

Indeed we can. All of the models show the Arctic Oscillation, which has been stubbornly high in recent weeks, diving sharply down, perhaps two or three standard deviations below normal. This is good. The North Atlantic Oscillation doesn’t look to dip quite as low, but still could reach below normal; for the first time (meaningfully) since late October. And the Pacific-North American pattern, which has been oscillating just below normal, looks to slowly rise. All of these trends are good, and I would expect some amount of moisture to rear its head in the next two weeks.

Cold air damming saves the snow

There may yet be skiing on Christmas. Despite temperatures in the 50s in Boston eating away at all the snow, much of Maine might not make it out of the 20s. However, the temperatures will be very localized, so some areas may see grass, while others see a protective layer of ice, one which can (hopefully) be ground up with the powder below and renovated in to decent skiing. Here are a couple of things which may affect the temperatures:

  1. Elevation. Above 2000 feet will actually be quite a bit warmer than below. It’s 42 on the summit of Mount Mansfield. And in the low 20s at Lake Champlain. As long as the inversion doesn’t mix out—if the winds don’t circulate down to the surface—the cold air may remain trapped at lower elevations.
  2. The orientation of the valley. There are three main drainages in Northern New England. The Champlain Valley drains north to the Saint Lawrence. The Connecticut south. And the Saco/Androscoggin drain east to Maine. In general, if the valley drains north or east, low-level wind flow will allow cool air to drain in. For the Connecticut, warm air will be able to surge up from the south. And Maine will remain coolest—most of the low parts of the state are stuck in the 20s, and may well stay there.

Looking at current snow depth maps, the deepest snows are east of the Greens, east of the Whites and in the hills of Southwest New Hampshire. East of the Greens is in the Connecticut valley, and may warm up dramatically. The Southwest New Hampshire hills have some Connecticut influence, and are quite far south to survive. But east of the Whites? There’s the jackpot. Temperatures should stay in the 20s and 30s all weekend, and what rain does fall should freeze solid. If the ice isn’t too bad, it should preserve the base. So, Jackson, Carters and Sugarloaf and anything in between, you win. You’ll have an icy mess of a base, but still a base. So there should be somewhere to ski next week.

Survival

So. This weekend.

It could be worse, snow retention-wise. The models are surprisingly forthcoming in an overriding/cold air damming event. In other words, warm air will rise up over the cold air in place, which will be anchored by a high to the north, setting up freezing rain. This is not a good thing, necessarily, for anyone, but if it’s not pouring and 55º, it’s better for the trails. Having said that, an inch of ice can be absolutely detrimental; it nearly sunk Windblown in 2008. So there’s no particularly good alternative here. Perhaps the best would be a bit of ice to coat the trails, and then a cold-but-above-freezing rain to keep them from melting. So while there should be snow once it refreezes next week—most of the area has more than a foot on the ground—it could be hard to get through the fallen trees.

Holy … ice storm?

Hey, it’s snowing today. Huzzah!

This weekend? Ugh. First of all, the models are still out. But the long and short of it is there’s a bunch of cold air to the north. A front will push north through southern New England and then get stuck somewhere between the Mass/NH border and Quebec. Somewhere.

What might happen is that it rides north and it rains and gets warm and the snow melts. Another (unlikely) thing that may happen is that the front will be suppressed and someone up north will get quite a storm. Most likely, it appears that the front will stall out somewhere in Northern New England. Now, thermodynamics. Cold air is denser than warm air. Warm air rises up over cold air. Precipitation falls through warm air, and then in to cold air, and freezes all over everything. It probably wouldn’t be anywhere near the Ice Storm (of 1998, although that shouldn’t necessitate any explanation). But the current GFS model is showing an inch of ice in some of Northern New England, which is not good (although decent for preserving snowpack, it’s hard to groom and hard to get to the trails in the first place).

If that run verifies, the worst of the icing would be to the east of the White Mountains, from Berlin and Fryeburg north and east in to Maine. Hopefully we’ll have some solution without ice, but without the snow getting washed away.

Quick model update

The 00Z runs of the American models are coming in further northwest of previous runs. This spells doom for the coast, but might push snow totals inland higher. A foot looks likely for much of Northern New England, with perhaps more in Northern Maine. Maybe a little less in the valleys.

Morning update: Not much change. A bit of sleet perhaps even up in to most of Mass and southern New Hampshire, but that will sort of solidify the powder below. Most snow overnight; should be fine driving by noon tomorrow to go skiing. You know, if you’re in to that kind of thing.

Get it this week; next weekend might be a bummer.

A good hit for most of New England

For the last few days the models have bumped back and forth quite a bit. As it stands now, most everyone in New England will have enough snow to turn a little scratching around in to mid-winter conditions, or something close to it. Even ski areas in Eastern Massachusetts (Weston, Great Brook) should have full coverage. Some of the best skiing may be in Western Mass, and the southern parts of Maine, New Hampshire and Vermont. But areas to the north should see a fine foot, or close to it, of snow as well. Nearly everyone in New England should have some terrific skiing starting on Sunday, and the storm will be out early enough that driving up for a day trip should be in the cards. It certainly will be for me.

Looking ahead, the models are still showing a significant warm-up just in time for next weekend. Hopefully it will be diminished or pushed east, but there has been remarkable continuity over several models on this feature, showing an elongated trough with a strong southerly fetch. Hopefully it will have some snow and won’t be a huge net loss as we go in towards the holidays.