Tuesday, December 12, 2017

As Of Tuesday Morning, Northeast Snow Behaving As Expected

Forecast snow totals have not changed much from
earlier forecasts. Click on the map to make it
bigger and easier to see.
Well, it was snowing outside my St. Albans, Vermont window as of 7 a.m., as it was through much of northern New England, northern New York and into southern Quebec.

The forecast plan for the storm hasn't changed much at all from previous forecasts. We're now in Phase I of this moderate-sized event, with a steady light, sometimes moderate snow expecte to continue most of the day, and into the evening as you go further northeast into New Hampshire and Maine.

I am getting plenty of reports of slick roads across the region, with spinouts, traffic jams and such on several stretches of Interstate 89 and other roads in Vermont.

Pretty much everyone in the region is affected by this Phase I. It's also the warmer half of the storm, and by afternoon, the snow will become somewhat wetter and heavier especially south of Route 2 in Vermont as temperatures flirt with the freezing mark for a time.

In far southern Vermont and New Hampshire, the snow will probably mix with or change to rain for a time today.

As we get more and more into the evening, the precipitation will lighten up as we prepare for a colder, windier Phase II of this storm.

By Wednesday morning, the wind will have switched to the west and northwest and the storm consolidates to our northeast and strengthens. This more powerful storm will kick moisture back through northern New England also cause the winds to increase and the temperature to drop. It will truly be a wintry day in the North Country with snow, blowing snow, and a lot of chill.

As mentioned yesterday, this Phase II will favor the mountains of northern New York, central and northern Vermont, the northern half of New Hampshire, northwestern Maine and southern Quebec.

It'll be a ski resort's dream, with not big huge additional accumululations in the deeper valleys, but lots of additional snow up in higher elevations.

The predicted snowfall is still the same as yesterday. Totals will be in the three to seven inch range in the valleys of northern New York, Vermont and central New Hampshire. The higher elevations are still in for a solid six to 10 inches, with locally higher amounts. (Especially around Jay Peak, Vermont)

Be careful on the roads today through Wednesday, and skiers, get your equipment ready. It's a good start to the ski season.

Monday, December 11, 2017

Monday Evening Vermont Storm Update: Ski Areas To Rejoice

Compared to this morning, forecast snow totals
from the National Weather Service in South
Burlington, Vermont have been nudged up a bit.
Click on the image to make it bigger and easier
to se. 
The National Weather Service in South Burlington, Vermont has nudged their predictions for the expected snowfall Tuesday and Wednesday upward a little bit.  

This is especially true in the mountains.

The storm is coming in from the west, which means it won't initially have all that much moisture to deal with. That usually means we won't get that much snow.

But this is a strong, dynamic storm, if moisture-starved at first, so it will be efficient at laying down some pretty good snows.

Although this storm track and strength is somewhat unusual, I've seen it before. And what usually happens with this type of scenario is the valleys, especially in western and southern Vermont, get "meh" accumulations, but the mountains (read, ski areas) make out like bandits.

The South Burlington NWS has expanded winter storm warnings to cover all of Vermont except the Champlain Valley and the western half of Rutland County. The western half of Bennington County, covered by the NWS office in Albany, also escapes the winter storm warning.

Winter storm warnings are up for New York's St. Lawrence and Mohawk valleys. The northern half of New Hampshire and northwestern Maine are also covered by the winter storm warnings.

Areas I've not mentioned are generally under winter weather advisories, which implies slightly lower snow accumulations.

As I mentioned this morning, the storm will come in two phases. The first is during the day Tuesday. Interestingly, the eastern side of the Green Mountains will get the most snow out of this first phase. The western slopes of the Greens, definitely covered under the winter storm warning, will miss out, and get fairly light snow.

Expect a general two to six inches of snow, with locally more, during the first phase. The "locally more" will be mostly along the eastern slopes.

Phase Two comes in Wednesday, when the wind shifts to the west and northwest. That's when the western slopes of the Greens get clobbered and the eastern slopes get much lighter stuff.

Although the entire region - Vermont, northern New York, northern New England and southern Ontario and Quebec will feel the effect of this storm, the type of storm and its track is one of those that I like: Not quite as bad in the valleys with only moderate accumulations, but hefty totals in the ski country of the Adirondacks, Green Mountains, White Mountains and the Laurentians.

This is a long duration storm, so even in the valleys, the commutes during Tuesday morning and afternoon, Wednesday morning and probably Wednesday evening will be affected.

Overall, accumulations will be a bit higher region wide than we said this morning, if National Weather Service forecasts turn out to be accurate. It looks like six or seven inches in the Champlain Valley with up to a foot in the mountains.

This storm looks made for the northern Green Mountains. I wouldn't be surprised to see 18 inch totals near the summits of places like Mount Mansfield and Jay Peak.

This snow will stick around for awhile, as it is expected to remain relatively cold for the next several days at least.

Unlike November, which had an unusually quiet weather pattern, the rest of December looks active, with frequent chances of precipitation. (Notice I said precipitation. I'm not guaranteeing just snow between now and Christmas. Could be some mixes or rain at times, too, we'll see.)

Still, I think the chances of a white Vermont Christmas look pretty decent. Time will tell.

One interesting thing is that in the winter

Moderate Sized Snowstorm Due In Vermont, New England Tuesday

Here's what the National Weather Service in
South Burlington is currently expecting for snowfall
through Wednedsay. Click on the image to make
it bigger and easier to see.
As of early Monday morning, we're still on track for a mid-sized snowfall Tuesday and Wednesday here in Vermont, so we'll have to deal with the usual wintertime slick roads, snow shoveling, and playing in the fluff.

You knew this would come eventually.

Before we get into Tuesday's main event, note that it is snowing in much of northern Vermont and New York this morning. Accumulations in most spots are around an inch, locally more in the mountains. It's enough to make the roads slippery, so give yourself extra time going to work today.

You'll need to do the same tomorrow. This storm is an Alberta clipper, coming in from the west. Usually, these clippers are not that big a deal. They usually toss one or two inches of snow on us and then move on quickly.

This one, however, has got more oomph than most of them, and its track is just perfect for a good dose of snow in northern New York, the northern half of New England and southern Quebec.

There's actually going to be two waves of snow. The first, on Tuesday, will pretty much affect all of us with a general three to seven inches of snow, with maybe a bit more than that on some of the eastern slopes of the southern and central Green Mountains.

A lull in the snow will probably come later Tuesday afternoon or the first half of Tuesday night as the storm goes by. But then the storm will consolidate and start to intensify fast just to our east. That will throw snow back our way.

It'll mostly affect the Green Mountains of Vermont on Wednesday, and also slam northern New Hampshire and much of Maine with quite a bit of snow, too. As the storm gets strong, northwest winds will pick up. Gusts Wednesday will reach at least 30 mph, which is more than enough to cause quite a bit of blowing and drifting. I guess Wednesday's commute is going to be annoying, too.

The bottom line: Most valley dwellers in Vermont can expect a total of three to eight inches of snow through Wednesday. That's where a winter weather advisory is posted. Those of you who live on the western slopes of the Green Mountains or in the Green Mountains can expect six to 12 inches through Wednesday. Those areas are under a winter storm warning through most of Wednesday.

It looks like the St. Lawrence Valley of New York, parts of New Hampshire and a good chunk of Maine will also see a good six to 12 inches of snow out of this one.

Thursday will be the coldest day of the winter so far, with daytime temperatures in many areas staying in the teens, with lows flirting with 0 Friday night. Temperatures will moderate into the weekend.

Sunday, December 10, 2017

First Winter Storm Watch Of Season Posted For Vermont

Winter storm watch (dark blue) covers all of Vermont
and much of the rest of northern New York and
New England Tuesday. It'll be the first decent
snowfall of the season in northwestern New
England,  but it won't be extreme:
Expect four to seven inches. 
Just a quick Sunday evening head's up: We're now under a winter storm watch here in Vermont from late Monday night through late Tuesday night.

We've known for days that we had a high risk of snow on Tuesday, and now that risk is becoming more certain. It's going to snow like hell.

Don't worry, "snow like hell" is all relative. This won't be Storm Of The Century by any means.

But you want to take this seriously, like all winter storm watches. The Tuesday morning commute in Vermont and most of the rest of New England is going to be challenging.

You want to plan now for a longer commute than usual, icy roads, and the random idiots who don't know how to drive in the snow, despite the fact many of them have lived in wintry Vermont for decades.

Like I said, this won't be an epic snowstorm. Right now, the general consensus is a four to seven inches snowfall in Vermont and surrounding areas. Hey, at least this will brighten the dark December landscape.

I'll have much more on this during my Monday morning update.

"Deformation Zone" Snow Dumped Extra Snow On Narrow Northeast Bands

Radar imagery from Saturday evening showing two
"deformation bands" with heavier snow (in green)
 One extends from coastal Delaware and New Jersey
 into southern New England, while
another longer and more defined one runs from
northeastern Virginia all the way to Maine.
Something weather geeky fascinated me during the snowfall that hit the East Coast yesterday as that southern snowstorm headed north and east and off the New England coast.

The storm had some of the longest and most defined deformation zones of any storm I've seen in awhile.

I know, I  know, I'm already getting you in the geek weeds.

Very often with nor'easters - and this storm was a relatively weak semi-nor'easter - a narrow band of heavy snow sets up and stays nearly stationary to the northwest of the storm.

Under this band, people often get much heavier snowfall than everybody else affected by the storm.  Sometimes there are two or even more narrow bands of heavier zone associated with deformation zones.

Here's why we get deformation zones. To the east of a storm, there's usually basically a conveyer belt of warm, wet air heading north. This warm air finally reaches a warm front associated with the storm. The warm, wet air crosses over the warm front and is forced to rise up and over the cold air to the north of the front.

As this happens, some of the rising air curls west toward the northwest flank of the storm. Other parts of the warm moist air rise and curl to the east. The more rising air you get the more likely you are to get precipitation and the heavier it is likely to be. Also, since the warm air aloft is splitting away, west and east, other air has to replace the warm stuff that split off and away. So even more air has to rise to replace the "missing" air.

So now we have two reasons why the air is rising. Which means it rising most on that narrow band where the warm air is splitting aloft. So you get a lot of precipitation in that narrow band. That's pretty much what happened yesterday.

The storm wasn't all that strong, so snowfall amounts weren't huge. Under one band, six or seven inches of snow fell from south of Albany northeastward into the Massachusetts Berkshires and far southern Vermont. A few miles east and west of this band, snow totals were closer to three inches.

In very strong storms, snowfall in a deformation zone can be really impressive. A deformation zone is a good part of the reason northwestern Vermont and northeastern New York were hammered by two to three feet of snow during the blizzard we had this past March 14.

Almost every nor'easter has a deformation zone, so we'll almost certainly see more of them this winter. The next chance of snow in New England and across Vermont is on Tuesday into Wednesday. Don't know yet if we will be dealing with any deformation zones, though.

Saturday, December 9, 2017

Southern Snowstorm One For The Record Books. In Northeast - Meh

Aerial view of Corpus Christi, Texas Friday, with
its palm trees all weighed down by heavy snow. 
I'm still amazed by the huge area of snow that fell Thursday and Friday along almost the entire Gulf Coast, which rarely gets snow.

And the amazing thing is the real estate the snow covered. All the way from Brownsville, on the southern tip of Texas, all the way to Pensacola, on Florida's panhandle. College Station, Texas, got five inches of snow, the most since 1949. Some of the higher spots around Corpus Christi, Texas got up to 7 inches.

As I mentioned yesterday - and it bears repeating because it's so amazing - As of Friday afternoon, Corpus Christi has had more snow so far this winter than Denver, Boston, Caribou, Minneapolis, Chicago, Cleveland and Detroit combined!

Mobile, Alabama, right on the Gulf Coast, got an inch of snow, the earliest on record there. Data in Mobile goes back to 1881. Carrolton, in northwest Georgia, picked up 10 inches of snow, and up to 15 inches was reported on the hills near Ashville, in western North Carolina.

The storm brought lots of joy to people in the South who aren't accustomed to snow, but also headaches. There were quite a few car crashes and up to 250,000 people lost power as snow accumulated on trees that still had leaves. Up to 625 flights were canceled at Atlanta's airport.

Now, as expected, the storm is making its way to the northeast, and will lay down a stripe of snow all the way to Maine and the Maritime Provinces of Canada.

At least when you get further and further north, a moderate sized snowstorm is no big deal for December. Still, there are winter storm warnings in patches in and around Virginia, parts of New Jersey, Delaware and southeastern New England. Areas in between these warnings are under winter weather advisories. There will be anywhere from four to 10 inches of snow from Virginia to Maine today and tonight, with locally higher amounts.

Here in Vermont, we're still looking at one to three inches of snow east of the Green Mountains with very little in northwestern Vermont. A series of weak disturbances and cold temperatures next week will whiten the ground nicely in those parts of Vermont that totally miss out on the snow tonight.

Friday, December 8, 2017

Very Odd Southern Snow To Become Normal Eastern New England Snow

Students at Texas A&M in College Station, northwest
of Houston, were able to make this large snowman
amid a very rare snowstorm last night in that
part of the country
Overnight and this morning it snowed in southern Texas and northeastern Texas, and this there are winter storm warnings from southern Mississippi to northern Georgia.

This wildly early snowfall so far south comes when northern areas are still waiting for snow. There was more snow on the ground in southern Texas cities like San Antonio and Corpus Christi than there is at my house not far from the Canadian border in Vermont.

The season's first snow accumulations hit Laredo, Texas and the Houston metro area earlier in the month than cities like Boston and Des Moines.

In fact, Corpus Christi has more snow than Denver, Boston, Caribou, Minneapolis, Chicago, Cleveland and Detroit combined!

Thunder snow was reported in Corpus Christi, Texas, perhaps for the first time on record. Baton Rouge also got thunder snow this morning. And last evening, it was colder in Corpus Christi (35 degrees) than it was in Fairbanks, Alaska (36 degrees). Fairbanks normally hovers well below zero this time of year.

Jackson, Mississippi has had 2.5 inches of snow so far, the most since 2010. It snowed in Brownsville, on the southern tip of Texas, for the first time since 2004. It also snowed across the border in Mexico. So far, Lake Charles, Louisiana has had 2.1 inches of snow, the most in a single storm since 1973.

The culprit was a storm that took a far southern route through near the Rio Grande and into the northwestern Gulf of Mexico. That path allowed the storm to draw cold air far south into Texas and the Gulf Coast states, prompting the early season snow.

The storm will zip northeastward, off, but parallel to the East Coast later today and Saturday.  It will lay down a stripe of snow from the Southeast, through the southern Appalachians, and basically all the way up Interstate 95 to Maine. Boston, still waiting for its first snow of the season, will probably, finally get a few inches.

Most places along the path of the storm will get two to six inches of snow, with locally higher amounts in the central Appalachians and the eastern half of New England, where upwards of eight inches might fall in some spots. At least once you get to the Northeast, it's normal to have snow in December. The Texas snow thing is definitely weird, though.

Here in Vermont, the snow will clip the state, but it won't be a huge deal. Maybe a couple inches in the Connecticut River valley and less elsewhere. However, this will have to be watched. So far, this storm is overperforming, causing more snow and havoc than expected. It's possible we could get a little more than what's forecast now.

Even if we don't get much of anything from this one, fear not, winter lovers: It's been snowing off and on in the mountains since Wednesday night, and Vermont will get frequent bouts of light snow and snow showers through next week as a series of weak storms and fronts repeatedly hit us amid chilly, subfreezing temperatures.

What snow we get here in New England will stay on the ground for days or longer. Not so in Texas. San Antonio is expecting highs in the 50s today, and in the 60s to around 70 through the weekend.