Friday, March 31, 2017

Friday Evening Update: Snow Forecast Miraculously On Track, But....

Road conditions looked terrible in high elevation Mount
Holly, in south-central  Vermont as of 5:30 p.m. Tricky
road conditions will spread to the valleys overnight. 
Amazingly, the late season winter storm blowing into New England now has been behaving pretty much as expected, but it's still early in the event.

I say "amazingly" because this is one storm forecast that was guaranteed to have wild inaccuracies.

That's still true, though so far so good on many of the forecasts. However, there are already changes afoot that could easily change how much snow any given area gets.

One minor thing that's change so far: Far northern parts of New York, northern Vermont and northern New Hampshire has had almost no precipitation so far.

Just a trace of mixed rain and snow sprinkles so far at my house in St. Albans, Vermont as of 5:15 p.m., and just 0.05 melted in Burlington, Vermont.

That's about to change as the main body of precipitation was moving north as of 5:15 p.m. It looked like steady precipitation was just about to begin outside my house as of 5:20 p.m.

In most, but not all areas of New England, the overall philosphy of who will get what by the time with this is over hasn't changed all that much since yesterday.

It still looks like the "biggest loser" - if you like snow that is - would be New York's St. Lawrence Valley and the northern Champlain Valley of New York and Vermont.

There, only two to four inches of snow is expected, but again, this might be a bust. Could be much more could be much less, as temperatures are marginal. The Champlain Valley could easily end up being the storm's biggest surprise area, with either much more or much less snow than current forecasts.

Weak sun heat coming through the clouds has kept it a rain/snow mix so far. in the valleys.

Here's why it's complicated. Warm air is trying to move in aloft, with suggests it would be mostly rain for the first part of tonight for valleys in New England, including Vermont.

On the other hand, heavier precipitation is moving in. Heavy precipitation tends to cool the air a bit, which suggests more snow would come.

Which one wins out? I don't think we'll know until the storm is pretty much over Saturday

I'm still confident that middle and higher elevations in most of Vermont, the Adirondacks of New York, most of New Hampshre, northern Massachusetts and southwestern Maine are going to get clobbered.

This is a very wet storm, and the wettest part will be across central and southern New England. I'm sure we'll get quite a few reports of a foot to 18 inches of snow in many of these areas.

One major change in the forecast involves Massachusetts. It looks like colder air will hang tough in central and eastern Massachusetts, so they're going to get more than four inches of wet snow. Possibly up to 10 or 12 inches.

A winter weather advisory for the Boston area, for example, has been upgraded to a winter storm warning for up to eight inches  of snow.

Areas near the southeastern Vermont/southern New Hampshire/far northern Massachusetts area look at this point to be the hardest hit, with an expected 12 to 18 inches of snow with the consistency of wet cement.

In other words, heart attack snow. Don't shovel unless you're totally, totally fit.

Also in many parts of central and southern New England, including southern Vermont, there could be a period of very heavy sleet tonight.

Some areas could also get a dangerous period of freezing rain in a few parts of central and southern New England. Teasing out precisely which towns might get this is still tough.


As I said this morning, anybody who gets a lot of wet snow and sleet is prone to power failures tonight and Saturday, so be ready for that.

I checked the Vermont Outage Map at 5:20 p.m. today and there's no major power problems. That would come later tonight.

Also, road will all be crappy region wide Saturday morning, so postpone trips until later in the day.

Regionwide, precipitation will taper off during the day Saturday and temperatures will rise to a little above freezing, so road conditions will improve in the afternoon.

More "good" news. Another storm, very similar to tonight's,  is possible Tuesday in New England. However, that storm looks slightly warmer than the current one, so there will probably be more cold rain and less snow and sleet in the valleys than tonight's  storm contains

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