SPOKANE, Wash. — This year's solar maximum is proving a treat for those who enjoy the northern lights. Another opportunity is likely to dazzle the skies Thursday night across the northern hemisphere!
I've said time and time before, aurora forecasting is challenging at the best of times, but there are a lot of reasons to be very optimistic for Thursday night. First of all, the Space Weather Prediction Center (SWPC), has placed October 10-11th under a "G4 (Severe) Storm Watch," saying "A fast coronal mass ejection (CME) erupted from the Sun the evening of 8 October, 2024, and is likely to arrive at Earth on 10 October."
The modeling of the solar flare has the charged particles interacting with earth at 7 a.m. PST on Thursday, October 10th. While, yes, that's in the middle of the day, the stream of energy can last several hours, or sometimes a day or two after the initial burst.
Usually, aurora are visible at G3 conditions, with G4 even stronger, and G5 is the highest level. This is related to the KP-Index, which also measures the solar storm strength. The G3 equivalent is KP-5, G4 is KP-7, and G5 is KP-9.
Let's use these thresholds to compare what the forecast will be versus recent events. Last Monday night, the aurora was stunning, and the KP-Index hit a 7.3, which is impressive. If you remember May 10th's aurora, which was directly overhead and some of the brightest northern lights the Inland Northwest has seen in decades... that hit the maximum KP-Index of a 9!
We're hopeful that the KP-Index should at least reach a 7, since the observed CME was stronger than the previous one this week. So keep your fingers crossed and happy viewing!