Bright Moon Vs. Upcoming Geomagnetic Storm

A young angler at Brighton Beach in Duluth checks his line as the nearly full moon rises with Earth’s shadow over Lake Superior Saturday night. Bob King

The moon rose last night 99% full and made for a spectacular sight just after sunset. It’s amazing how much detail you can see on the moon’s face in early twilight when it’s light is only a little brighter than the background sky. The blotchy rayed craters Copernicus, Aristarchus and Tycho and a full spate of lunar “seas” were plain as could be. Later, with the moon higher and so much brighter in comparison, it took more effort to see such things.

That same moon, with a bit of the rind missing, will grace tomorrow night’s sky as well, but its presence may not be as welcome. Space weather experts with NOAA are forecasting a significant geomagnetic storm to begin tomorrow (Monday afternoon) and continue through the night Dec. 4-5. Peak activity should be from sunset to midnight (CST) when a level 2 or moderate storm is expected. High speed solar winds flowing from a recent “hole” in the sun’s corona will supply the ammo.

Normally, that would mean northern lights across the northern third of the U.S., but the moon toddles up from the horizon about 6 o’clock local time just as twilight is giving way to night. Although not as bright as a full moon, the waning gibbous moon adds a lot of light to the sky. Assuming NOAA is right, will we see it?

My guess is yes — at least early on before the moon gets high enough to throw its full radiance about. Tomorrow night, make a point to eyeball the northern sky now and then. IF the aurora really kicks in, it may be visible later in bright moonlight, but early is best based on moonrise and the forecast.