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| Today's updated snow forecast map from the National Weather Service office in South Burlington. I think mountain summits might get more snow than depicted here. Biggest bust potential is in valleys as marginal temperatures could leave those areas with much more, or much less snow than forecast. |
That said, this is such a complex storm that changes and surprised are inevitable.
Another factor is how late in the season this is for a winter storm. The high springtime sun angle managing to allow some heat through the clouds during the daylight hours will influence how much snow piles up and how much rain will mix in, especially in the valleys.
What follows is the scenario the National Weather Service and other meteorologists think will happen with this big, weird spring storm.
You'll see adjustments in the forecast between now and tomorrow. Some of you will get more snow than forecast, some of you will get less. The timing and intensity of the storm are subject to some switcheroos.
Still, this is a pretty good summary will what will probably happen. The broad brush ideas on this forecast are pretty solid.
Today is the stereotypical, lovely calm before the storm. The day dawned clear and crisp, but it will warm up to near 50 degrees as high clouds ahead of the storm dim the sun somewhat this afternoon.
Then we gradually get into the storm.
TONIGHT
Increasing clouds, becoming breezy, there might be some scattered late night showers of rain or snow, but nothing to worry about. Your trip to work early tomorrow morning should be fine, with no major hazards on the roads.
WEDNESDAY
The storm starts to invade, but only in fits and starts at first. The original storm, source of a severe weather outbreak in the Midwest today, will be in the Great Lakes by midday. It will swing a weather front our way, which would encourage some showers of rain and snow.
Current forecasts have highs near 40, but if a little sun breaks through the clouds, it could be a bit warmer. If that happens, showers will be more convective. You know, the towering clouds that cause fitful bursts of precipitation. There's even a very low risk of a rumble of thunder.
Meanwhile, winds will be increasing from the southeast, and it will get pretty blustery. Gusts could reach 40 or 45 mph in some areas by afternoon.
As all this is happening, the new, more important storm for us will be taking shape in the Mid-Atlantic states. That will become the main nor'easter. Precipitation - rain and snow - will begin to pick up in the afternoon.
The winter storm watch for much of Vermont starts Wednesday morning, but I don't think we'll see many real impacts on roads and such until we get well into the afternoon. At least for most of us.
WEDNESDAY NIGHT
The peak of this mess arrives and it will truly be a stormy night.
The nor'easter by then will send strong east winds our way, along with boatloads of moisture. Wet and heavy snow will blossom overnight and come down hard, especially at elevations above 1,000 feet. Some sleet might mix in.
In warmer valleys, it might take awhile for rain and a mix to fully transition to snow, which would limit accumulations some in places like the Champlain Valley.
Those winds will be nasty, too. The high wind watch that the National Weather Service issued yesterday for Rutland County has been expanded to include eastern Addison and Chittenden counties.
Those east winds will gain momentum heading downhill on the western slopes of the Green Mountains, so gusts in the high wind watch zone could reach 65 mph. .Definitely enough to cause tree and power line damage.
Elsewhere, winds overnight Wednesday could gust to between 40 and 50 mph.
Combine those gusty winds with all that wet, heavy snow coming down, and you can see why people are worried about power outages.
We caught a break with the spring snowstorm we had back on March 22, when the snow was more powdery than expected. I seriously doubt we'll get a similarly break this time. Power outages are a risk with this one statewide.
No one will be immune from the power outages, but they'll be especially prevalent at elevations above 1,000 feet, where snow will be heaviest.
THURSDAY
Still nasty. The roads in the morning will be snow covered and slippery. Some back roads might well have trouble with fallen trees and branches. Power will be out for some of us.
The winds will start to diminish, so that's good. With daylight, the temperatures will rise a bit. Snow will mix or even change to rain in the valleys and snow on the ground there will settle a bit. The wet snow will continue in mid and high elevations, so new power outages could continue.
Precipitation rates will mostly get lighter as the day wears on, too.
THURSDAY NIGHT -SATURDAY
The storm will essentially stall near New England will gradually weakening. During Thursday and Friday nights, the rain will turn to snow again in the valleys, with light accumulations. It will probably switch back to rain during the day.
Higher elevations will continue to pile up the snow, but at a slower rate than on Wednesday night and Thursday.
The precipitation will keep getting lighter and lighter and spottier and spottier until it quits altogether hopefully by Sunday.
Total accumulations are tricky, especially in the valleys. That's because it will accumulate at times, melt at other times.
Deepest snow depth during this whole episode in warmer valleys will probably be three to six inches. Areas under the winter storm watch, which encompasses mostly elevations above 1,000 feet in Vermont, will probably top out anywhere between six and 18 inches through this mess.
Some mountain summits - I'm talking just the tippy top of the Green Mountains and Adirondacks - could close in on three feet of new snow by Saturday.
MONDAY
Fingers crossed on this one. Our storm will be well offshore by then. High pressure will be trying to nudge in. We'll be in between, in a zone of sinking air. If you want to actually see the eclipse, you want sinking air, as that tends to destroy clouds.
A back door cold front, or patches of moisture pinwheeling back into New England still might spoil the show, but for now, chances look good for at least partly clear skies Monday afternoon for the long-anticipated eclipse.
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