WASHINGTON >> Scientists say a Valentine’s evening solar flare is causing radio disruptions and may put on a cool sky show Thursday and Friday nights in some northern regions. But they say the solar storm zapping Earth isn’t that big or troublesome.

Bob Rutledge, who’s lead forecaster for the government’s Space Weather Prediction Center, said the solar X-ray flare is the largest of its type since December 2006. But that’s mostly because the sun’s been unusually quiet for nearly five years.

This solar storm rates an R-3 on a five point scale. It’s on the weak end of what’s considered strong, but still there are about 175 of those every decade or so. Look for auroras in Alaska and other northern areas. Rutledge said some commercial airliners have reported radio disruptions, but no harm.