The "noctilucent daisy" continues to expand and intensify as summer unfolds. Observers in central-to-northern Europe are reporting vivid, nightly displays of NLCs. Just hours ago, Alan Tough photographed these over Lossiemouth, Moray, Scotland:
Noctilucent Clouds
© Alan C ToughNLC's at Lossiemouth, Moray, Scotland.
"This was another spectacular display of noctilucent clouds," says Tough. "I arrived in Lossiemouth in time to see the Moon rising and managed to capture its glitter path on the River Lossie."

2013 is shaping up to be a good year for NLCs. The clouds surprised researchers by appearing early this year, and many bright displays have already been recorded. Once confined to the Arctic, NLCs have been sighted in recent years as far south as Utah, Colorado, and Nebraska. They might spread even farther south in 2013.

Observing tips: Look west 30 to 60 minutes after sunset when the sun has dipped 6o to 16o below the horizon. If you see luminous blue-white tendrils spreading across the sky, you've probably spotted a noctilucent cloud.