Will the aurora show tonight? We’re all crossing our fingers. This was a nice display from May 2016. Bob King
The forecast still looks good for tonight for possible auroras, but let’s break it down so you’ll know what to expect. First off, last night and this morning there has been zero activity. Between 10 a.m. and 1 p.m. today, the Kp index, a measure of magnetic activity in the upper atmosphere, is forecast to reach “5.” Kp can range form “0” to “9.” The higher the number the more likely we are to see northern lights.
This is the 3-day forecast from NOAA published this morning. It shows Universal Time (Greenwich Time) time on a 24-hour clock along with the activity level or Kp index. Click for the most up-to-date forecast. NOAA
When the Kp reaches 5, skywatchers in the northern regions of the northern border states can generally see the aurora, but it’s on the quiet side — a low bright arc with few faint rays dancing about late in the evening. Kp 5 is the equivalent of a G1 or minor geomagnetic storm.
When the index reaches 6, it becomes a moderate or G2 storm. That means ...