Really Awesome Satellite, Ground Photos Of A "Dry Slot"

From the National Weather Service in South Burlington, Vermont.
Abrupt clearing behind a cold front Wednesday morning.  

An unremarkable, weak cold front passed across northern New England on Wednesday.

Unremarkable, that is, until you see the satellite photos of it. And to a lesser extent, what it looked like from the ground.

Sometimes, a "dry slot" curls up behind a cold front associated with a storm system.

A dry slot is when a storm gets wound up, and the dry, cool air that usually comes in from the northwest behind a storm gets pulled northeastward and wraps itself into the east side of a storm

This actually happens a lot.  But the photos of yesterday's dry slot in northern New York and Vermont are pretty cool.

In this case, the boundary between wet air and dry air at mid-levels of the atmosphere was abrupt, so you got the sharp boundary between totally overcast skies and totally clear skies that we saw yesterday.

Photograph taken in St. Albans, in northwestern Vermont less than an hour
after the satellite photo, above, was taken. From the ground,
you can still see the sharp line between cloudy and clear.  

Dry slots don't usually last long in any one location.

Usually, moisture also wraps around a low pressure system, and continued winds from the northwest draw the wetness from the east, over the the northern top of the storm, then southeastward into areas that had initially been clear.

That's what happened in Vermont Wednesday. Skies cleared, it got fairly warm for this time of year.

The temperature in Burlington, Vermont reached 58 degrees under those briefly sunny skies within that dry slot.

That's eight degrees above normal. Nothing extreme, but nice for November.

But the clouds and cooler air began to filter in by mid to late afternoon, and the temperature slowly began to fall

By Thursday, northern New England was back into the typical November regime of clouds. cold rain, high elevation snow and generally blah weather.