Skies of blue appeared above Washington on Monday afternoon, a sharp contrast to the days of gloom that came before.

As the famous Irving Berlin song had it: “Skies were gray but they’re not gray anymore.” Of course, neither real life nor meteorology is required to live up to every letter of popular song lyrics.

In Monday’s case, it might have been a bit of an exaggeration for newly optimistic and exuberant residents of this area to burst out with, “Nothing but blue skies . . . ”

At least in the early part of the day, clouds could be seen, a good sample of the gray clouds that had blanketed the area for a week, bringing record amounts of rain and plentiful helpings of gloom.

As for how the change came about, the National Weather Service gave a meteorological account of what greeted Washingtonians as they looked upward through the day.

It was a matter, it seems, of sublimation. In the process of sublimation, ice crystals, such as those that make up clouds high in the cold atmosphere, turn directly into water vapor.

Or, as the weather service has put it since late Monday morning, “the outer edges of the stratus deck have been sublimating away.”

In Monday’s case, that meant, as the weather service expressed it, that the layer of gray clouds overhead was “slowly dissipating and revealing a solid blue sky” over the Washington-Baltimore area.