Thursday, January 4, 2018

Huge Nor'easter Trashing The East Coast Now, As Expected

Awesome color-added satellite shot of the nor'easter
plowing into New England this morning. 
The remarkable, uber strong nor'easter is behaving just as forecast today, even though that behavior is really, really bad.  

The immediate coastline from South Carolina north has been pummeled. It was something to see video of the palm trees along Virginia Beach being pummeled by very strong winds, as if in a tropical storm or hurricane. But instead of heavy rain, it was a blizzard.

(To avoid confusion, this storm is NOT a hurricane, and has NOTHING to do with hurricanes. Hurricanes and nor'easters are two COMPLETELY different types of storms. I've heard this storm referred to as a "winter hurricane" and that is totally a wrong description.)

As of 9 a.m. the storm was engulfing New England, with the worst yet to come. Thunder snow was ongoing near southern Connecticut and Long Island at that hour. Blizzard conditions with snowfall rates of up to 3 inches per hour and gusts of 55 mph were reported in this area. Snow emergencies are up from Virginia to Maine.

This truly is a bomb storm. That reference is  partly media hype of course, but it's a thing. It's now confusing to many people, since it's been used this week both correctly and incorrectly in the media, so I'll have an explanation as to what a bomb storm further down in this update

Here in Vermont, it was snowing in the southern half of the state as of 9 a.m. and the snow was steadily working north. If you live in northern Vermont, it's best to get your stuff done out on the roads now, if at all possible. Things definitely go downhill this afternoon.

As I noted yesterday, this won't be a tremendously deep snowfall for Vermont - three to five inches west to as much as a foot to the east, especially in the Northeast Kingdom and the high elevations of far southern Vermont.

But, again, as we said yesterday, it's the wind and especially the intense oncoming cold that it going to get you. The expected 40 mph gusts will certainly blow a lot of snow around.

If  you've got time this morning, get your car's gas tank full, and put stuff like extra blankets and nonperishable snacks in the vehicle, just in case. The roads will stay treacherous into Saturday. First, even though this will be a dry, powdery snow, car and truck tires will compact some of it into black ice.

Blowing and drifting snow will hinder visibility and put snow back onto roads even after the snow stops falling from the sky Friday night and Saturday. Plus, extreme cold can easily cause vehicle break downs. If you get stranded for a few hours or even minutes, the emergency pack in your car can really help. Better safe than sorry. If possible, hunker down at home and read that really good book you got for Christmas.
This snowfall prediction map is about as good as any.
Areas in pink can expect at least six inches of snow.
Greenish areas are up for more than a foot. 

The temperature and wind forecast for the storm and post-storm hasn't changed, either. The frigid conditions are the real story with this storm and Arctic outbreak. Expect dangerous wind chills starting tonight and going through Saturday night. Temperatures will fall below zero late tonight or early Friday and stay there until Sunday afternoon.

Wind chills as low as the 40s below can be expected later Friday through Friday night and well into Saturday. Actually temperatures will be in the 20s and 30s below in Vermont early Sunday morning.

High temperatures Saturday might not get any warmer than minus 10. If the temperature stays at 9 below or colder in Burlington Saturday, that'll be the coldest day since 1981. This is quite the nasty cold spell. It's among the worst I've seen in the past two or three decades.

The worst drama with this storm will come early this afternoon along coastal New England with high tide arrives. Forecasters are still expecting a storm surge that could exceed three feet above normal high tide in parts of southeastern Massachusetts.

Huge waves amid gusts as high as 70 mph and chunks of ice from the previous week's cold will become battering rams against shoreline structures. The storm surge will also probably be slow to recede, and could end up freezing in place.

As I said yesterday, more active weather is coming next week, but I'll get into that more after this storm blows by.

Now, let's get into bombs, shall we?

BOMBING STORMS

One of the top trending hashtags on Twitter since yesterday has been #BombCyclone in reference to the big nor'easter we're getting.

First of all, the cyclone part of that hashtag can be a big confusing to people. After all, cyclones are hurricanes near India. However, meteorologists often refer to any sizable storm as a cyclone. In this case, as I said earlier, this nor'easter has nothing to do with hurricanes. It's not tropical, it's not warm core. It does not depend on warm water to form.

This nor'easter formed because there was a lot of energy in the atmosphere, and there was a major clash between very warm, wet air over the Atlantic Ocean, and Arctic air plunging down from Canada.

But this storm IS a bomb.  But that's not a new term. Meteorologists coined the term a bombing storm around 1980 to a storm that intensifies very fast - explosively.

Storms are areas of low atmospheric pressure. Air pressure in storms is lower than the atmosphere surrounding them. The lowest pressure in a storm is right in the middle of it.

In general, the lower the pressure in a storm, the stronger the storm is. If the pressure in the middle of the storm is getting even lower, the storm is strengthening. If the pressure in the middle of the storm is rising, it's weakening.

Meteorologists use a unit of measure called the millibar to measure the pressure in storms. (Or anywhere in the Earth's atmosphere for that matter.)  If a storm like this nor'easter's central pressure drops by 24 millibars within 24 hours, it's a bomb cyclone.  

This storm more than qualifies. Its central pressure dropped by 48 millibars between yesterday morning and this morning, which is double what was needed to be considered a bomb.  And the storm is still bombing away as it's still strengthing rapidly.

By the way, bomb storms are actually quite common. They happen at least several times of year  along or off the east coasts of the United States and Canada.  Several more occur elsewhere every winter in the North Atlantic and North Pacific. The reason why you're hearing so many bomb references today is because this storm is affecting a lot of people. And this one's even bombier, to coin a word, than many other bomb storms, since it's strengthening so fast.

Many storm "bombs' go off well offshore, and these storms don't really affect anybody. They're too far away. So these distant bombs understandably get no media attention.

So, stay wary of this bomb, New Englanders, it's a nasty one. We'll provide more updates as news comes in.


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