Blame Out Of Season Temperature Inversion On Dank Vermont Weather

Spring flowers in my St. Albans, Vermont perennial gardens and bright
flags on my deck try to brighten up a very dreary Thursday
afternoon, but they can only do so much. 

For almost all of us Vermonters, this Thursday morning and afternoon has been an unpleasant exercise in chill, damp, clouds, fog and drizzle.  It's not the type of bright, blossomy May weather we expect, and feel entitled to this time of year.  

Blame it on a temperature inversion. It's warmer a few thousand feet up above us than it is near the surface.

This is the opposite of the usual regime, where it gets progressively colder the more you go up in elevation.

The warm-ish air up above locks us in the thick, chilly moisture and mist, as the atmosphere can't mix. Drier up above can't penetrate the "lid" the temperature inversion forms.

Since the drier air can't work its way down to us, it can't clear the clouds. The sun can't penetrate to warm us up. So, yuck.

These inversions are pretty typical in the late fall and winter. At that time of year, the sun angle is low and the light is weak.  If the sun is able to warm the air near the surface, it starts to rise, poking holes in the inversion up above until it finally breaks apart. In the winter, the sun just doesn't have the strength to pull that off.

The sun angle this time of year is much higher, so inversions are more rare. The sun usually can burst through, offering us a jail break from the gloom. Not today. The inversion is just too strong.

There's a slow moving weather front just to our south. Warmer air is feeding up and over that front and gliding northward, keeping that inversion sustained, despite what the sun wants to do.

South of the front, it's mild. It was 60 degrees at mid-afternoon in Bennington, which is just south of the front. Not super warm for early May, but much better than the March-like foggy 40s in the rest of Vermont.

So far today, the high temperature in Burlington was 45 degrees. That's not far from the coldest high temperature on record for the date, which was 41 degrees in 1953.

The inversion will break up tomorrow as a new, relatively weak storm comes in from the west and southwest. It will be a bit warmer Friday, but the overall weather won't improve much. It'll be in the 50s during the day - still a little chilly for this time of year. And there will be a lot of light rain and showers around.

You won't see the sun, so if you're craving it, you're out of luck.

Until Saturday, that is. By then, a little clearing will at least temporarily work in. The afternoon that day will feature some sun, and temperatures near 60 degrees. That's not too far from normal, so that's good.

With the forecasted sun and comfortable temperatures Saturday, it will be great if you want to participate in Vermont's Green-Up Day. That's when thousands of volunteers go out and clean up roadside trash. You ought to consider joining in.

But the weather pattern will remain active. We might not have more foggy, dank and drizzly inversions like we're having this afternoon, but we will have frequent bouts of clouds and showers for at least the next week or so.