JACKSON, Wyo. — Geomagnetic activity is expected to put on a light show in the sky on the night of Friday, May 10, and the action might be visible as far south as Wyoming.
According to the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center, on Thursday, May 9, seven coronal mass ejections were observed, along with several strong solar flares associated with a “large and magnetically complex sunspot cluster, which is 16 times the diameter of the Earth.” The resulting G4-level geomagnetic storm is considered severe.
Plasma from the ejections will interact with upper levels of the Earth’s atmosphere, generating the famous colors. Geomagnetic activity could be visible in the sky through Saturday night.
The Kp index is expected to reach level 8.33 overnight, peaking between midnight and 3 a.m. Some activity might be detectable beginning as early as 9 p.m. tonight, when the Kp index is expected to hit 5.33. Derived from the German “Planetarische Kennziffer,” or planetary index, the Kp scale runs from zero to nine.
As explained by Wyoming Stargazing, the Kp index “measures the disruption of the horizontal distribution of the geomagnetic activity…A value of zero means that even Fairbanks, Alaska would have difficulty in seeing the northern lights. One to three is most common, and that’s what is frequently seen in those northern latitudes of northern Canada and Alaska. A four would push them down into southern Canada, while a five, in the right conditions, might just barely be visible on the northern horizon here in Jackson Hole. To see them well, we typically need at least a six.”
A prediction by the Space Weather Prediction Center forecasts the aurora’s “view line” as passing through the bottom of the Cowboy State.
Visitors to Yellowstone National Park and Grand Teton National Park, away from light pollution, have a great chance of seeing the aurora tonight, so long as skies remain clear. Following the new moon on Wednesday, there should be little interference from the waxing crescent moon.
The National Weather Service’s Riverton Office forecasts clear skies in northwestern Wyoming tonight. Even if viewing conditions are perfect, though, it’s difficult to predict the aurora with much certainty.
“Space weather is very fickle,” National Weather Service Riverton meteorologist Chris Hattings says in the video above.
To view the aurora, head to a very dark place away from light pollution, and allow the eyes to adjust, which could take 15 to 30 minutes. Turn to the north-northeast and look at the horizon.
Jackson was treated to a beautiful Northern Lights display last September, captured in photos by Buckrail readers. Learn more about the mythologies associated with the aurora here.
