Be On The Lookout For Rare Noctilucent Clouds.

Meteorologists at the National Weather Service office
in Seattle, Washington took this photo of beautiful,
eerie and rare noctilucent clouds last week

 If skies are clear enough for the next few nights, take a look toward the north after dark. 

There's been an outbreak of rare noctilucent clouds, an eerie, beautiful blue glowing wispy cloud that is as high in the atmosphere as you can get. 

They're most likely to be seen near the poles in the summer. In early summer, they're sometimes visible in places like northwestern England, Canada, Alaska, that sort of thing.  Sometimes people in the northern United States get to see them. This year, they've been the most pronounced in decades.

Here's how the Washington Post explains these clouds:

"Noctilucent clouds, also known as polar mesopheric clouds, appear during the summertime in each hemisphere at about 50 miles high in the layer of the atmosphere knows as the mesosphere. They form when water vapor congregates around specks of meteor dust floating in the mesosphere and freezes, forming ice crystals."

They're usually visible not long after sunset and before sunrise. The clouds are so high up they are illuminated by the sun that has, at ground level slipped below the horizon. It looks like it might be clear enough tonight to go out and take a look toward the north,  just in case these clouds appear.

The Washington Post said there's a clear reason why this has been such a good year for noctilucent clouds. The mesosphere is an incredibly cold, dry place. There's little moisture up there to work with. But for some reason, at least by the standards of the mesosphere, it's wet up there. 

Another shot of the noctilucent clouds over Washington
State last week taken by NWS personnel.

Nobody is sure why. Perhaps it's rocket launches. There were 16 launches in June. It could have been the It could have been the huge Hunga Tonga volcano eruption back on January 15, which put a remarkable amount of stuff high in the atmosphere. The eruption could have dragged some moisture from the Earth's surface way up to the mesosphere.  It's so high up that I doubt climate change has anything to do with the increase in these clouds. 

Sky watchers are certainly excited about these clouds now.  Last week, the National Weather Service office in Seattle, Washington urgently tweeted that anyone who was awake at that late hour should head outdoors to see what they regarded as the best display of noctilucent clouds in decades. 

They had the photos to prove it, too. Other spectacular sightings of these clouds have been reported this past week over places like British Columbia, Denmark and Great Britain.

This won't last long.  As the days slowly start to get shorter, the chances of seeing these beautiful clouds begins to diminish.