Geeking Out On Vermont Mountain Waves And "Weathergami"

Satellite photo from Saturday shows clouds that
look like waves over northern New England. The
air behaves like a fast flowing river going up and over
a submerged boulder, which creates a series of 
waves downstream. 

We're geeking out on the Vermont weather this past Saturday. It was a typically blustery early November day. Kind of cloudy, kind of gusty, not a great day to be outside. 

But us weather enthusiasts always find something interesting in the clouds and the sky and the wind. Saturday, the wind and weather patterns created a couple interesting things

MOUNTAIN WAVES 

The blustery weather on Saturday created a classic case of mountain wave clouds in Vermont and elsewhere in northern New England. 

That type of cloud is pretty common around here, especially in the colder parts of the year. From the ground, they look like evenly distributed lines of clouds and clear skies. In satellite photos, they look like ripples on a lake. 

There's a good reason they look like ripples. Air flows like water. Meteorologists, after all, are basically fluid physicists. 

Have you ever noticed how water behaves in a fast flowing river when the water goes over a submerged boulder? The water goes up and over the boulder, and then there's a series of "echo" waves downstream from the boulder. 

The air behaves exactly the same way.  Strong west winds hit the north/south oriented Green Mountain range. The mountains are that submerged "boulder" and the air had those echo waves downstream from the mountains. 

You could see it in the clouds. The air cooled when it rose so moisture in the air condensed into clouds. Once the air gets over the mountains, the air sinks, so the cloud disappears. Then, downstream at the next wave, the air rises again, forms a cloud, and so on and so on. The clouds let you "see" the waves in the air. 

On Saturday, waves from the Green Mountains extended into New Hampshire. Plus, the Adirondacks, the White Mountains and the highlands of western Maine created their own wave clouds. 

Sometimes, mountain waves can be dangerous for aircraft, but in the case of Saturday's waves, and most of the time for that matter, planes can avoid the waves pretty easily and stay safe. 

"WEATHERGAMI"

That's a term I've never heard before.  It has to do with the temperatures on Saturday in Burlington. The high temperature was 45 degrees and the low was 43.  That combination of high and low temperatures has never happened before, according to the National Weather Service office in South Burlington.

A daily high and low temperature within two degrees is extremely rare. Even a four or five degree difference between low and high temperature is quite unusual. Usually the range is 15 and 20 degrees. 

A combination of an overcast and no change in airmass temperature during the day kept readings even all day. Had the sun come out, temperatures likely would have risen above 45 degrees. The air approaching us during the day was neither warmer nor colder than the air that was already here. 

That's different than usual, as the usually blows in warmer or colder air during the course of a day.   

The made-up term weathergami, is a play on origami, implying a symmetry or balance in the temperature. 

"Weathergami" seldom lasts long. By Sunday, the  high and low temperature in Burlington was 48/31, a pretty typical range for this time of year.