JACKSON, Wyo. — Geomagnetic activity is expected to put on a light show over North America for the next few nights, and the action might be visible as far south as Wyoming. A nearly full moon and potentially rainy skies might hamper visibility over Jackson Hole, however.
The National Oceanic and Atmospheric Administration’s Space Weather Prediction Center issued a minor to moderate geomagnetic storm watch for Aug. 8 and Aug. 9 following the observation of a coronal mass ejection on Aug. 5, along with a coronal hole high speed stream. Plasma from the ejection will interact with upper levels of the Earth’s atmosphere, generating the famous colors. Geomagnetic activity could be visible in the sky through Friday.
The Kp index is expected to reach level 6 overnight. Some activity might be detectable beginning as early as 9 p.m., according to NOAA’s data. Derived from the German “Planetarische Kennziffer,” or planetary index, the Kp scale runs from 0 to 9.
As explained by Wyoming Stargazing, the Kp index “measures the disruption of the horizontal distribution of the geomagnetic activity…A value of 0 means that even Fairbanks, Alaska would have difficulty in seeing the northern lights. One to 3 is most common, and that’s what is frequently seen in those northern latitudes of northern Canada and Alaska. A 4 would push them down into southern Canada, while a 5, 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 6.”
The National Weather Service’s Riverton Office forecasts a slight chance of showers and thunderstorms tonight between 9 p.m. and midnight, which would be the prime time for viewing the aurora. Mostly cloudy skies coupled with a moon that is estimated to be 97% full could interfere with skywatching.
Even when 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 has said about the aurora in past forecasts.
To view the aurora on a clear night, 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.
If tonight’s display doesn’t work out, relive the beauty of last May’s northern lights display, when a severe geomagnetic storm lit up the skies.
Keep an eye on the Space Weather Prediction Center to see how the forecast evolves.
