Meteor Clouds

Some of the greatest treats of June are the relatively rare but stunningly beautiful noctilucent clouds that form very high in the Earth's atmosphere during this time of the year.

Thursday night, there was quite a show, as illustrated by the pictures below.

Picture courtesy of SkunkBay Weather (from central Puget Sound)

Eastern WA

Noctilucent clouds form high in the atmosphere, about 50 miles above the surface, when water vapor condenses on meteor dust, producing small ice crystals that make up the clouds.

Such clouds are only apparent from late May to early August within a relatively narrow band of latitudes (roughly 50 to 70 degrees)--leaving Washington State on the southern edge of the viewable domain.

Why such limitations, you ask?

First, the formation of such ice requires very, very cold temperatures and the upper atmosphere (called the mesosphere) is coldest during late spring and summer.

Second, the clouds are best illuminated by the sun located below the horizon, and summer provides the optimum sun angle.