Aurora Watch: Moderate Storm Predicted Tonight

Moderate aurora storms feature one or more green-hued arcs and moving, vertical beams that can sometimes climb as high as the top of the sky. Credit: Bob King

Most aurora forecasts call for “minor” storming, what’s called a G1 geomagnetic storm. These are typically visible from the northern half of the northern tier of states. A moderate or G2 storm brings the northern lights further south into the Midwest, and that’s the prediction from NOAA for the next 24 hours.

The Kp index measures magnetic activity high overhead in Earth’s upper atmosphere. When it hits K=5, a G1 or minor geomagnetic storm is underway. The Kp index has been at 5 for most of today as Earth gets hit by high speed particle winds from the sun. Kp=6 indicates a moderate storm. Click to see the current index. Credit: NOAA

What does that mean for you and I? Make sure you take a look tonight at the northern sky for a greenish arc or even a series of beams or rays or light reaching toward the top of the sky both tonight (March 1) and early tomorrow night. This might be our best opportunity in recent months to see an obvious display.

Once again, a large hole in sun’s otherwise buckled down magnetic field, has allowed swarms of subatomic particles — a mix of electrons and protons otherwise known in the biz as plasma — to flow in Earth’s direction. Indeed, even as I write this, a G1 storm is in progress. Skywatchers in the Scandinavian countries and the northern UK should be spotting the aurora right now (4 p.m. CST).

This diagram shows the auroral oval for this afternoon U.S. time. Winds from the sun have connected with Earth’s magnetic field today, causing the oval to expand southward. Cities under or near the oval’s edge will see the northern lights. Click to see the current oval. Credit: NOAA

If the activity continues as forecast, we may see it here in the U.S. and southern Canada, too!

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