Sky watchers in parts of Northern California may catch another glimpse of the Northern Lights this week.NOAA's Space Weather Prediction Center issued a severe geomagnetic storm watch through Thursday. The center said a fast coronal mass ejection (CME) erupted from the Sun on Tuesday and there is the potential for a G4 geomagnetic storm upon arrival. That means an aurora may become visible across much of the northern half of the United States, as far south as Alabama to parts of Northern California, according to the center. Geomagnetic storms are measured from G1 (minor) to G5 (extreme). The scale is based on powers of 10, meaning a G2 storm is 10 times stronger than a G1 storm and so on.The storm in May that produced auroras across much of California and as far south as Florida was a G5 storm. On Monday, some people in Northern California reported seeing another aurora. As of Wednesday afternoon, NOAA's aurora forecast dashboard showed a possible view line extending into southern Oregon for Thursday night. Bryan Brasher with NOAA said auroras typically happen up to 250 miles above the surface of the Earth and view lines could extend up to 600 or 800 miles away."Aurora can weaken and intensify very quickly and there are times where they could be seen south of the view line, but that line is a best guess on the limit to which people could expect to have a chance to see them," he said ahead of the event.Aurora sightings are also reported on the NASA-funded science project Aurorasaurus. You can sign up to get alerts from the Aurorasaurus.See more coverage of top California stories here | Download our app | Subscribe to our morning newsletter
Sky watchers in parts of Northern California may catch another glimpse of the Northern Lights this week.
NOAA's Space Weather Prediction Center issued a severe geomagnetic storm watch through Thursday.
The center said a fast coronal mass ejection (CME) erupted from the Sun on Tuesday and there is the potential for a G4 geomagnetic storm upon arrival.
That means an aurora may become visible across much of the northern half of the United States, as far south as Alabama to parts of Northern California, according to the center.
Geomagnetic storms are measured from G1 (minor) to G5 (extreme). The scale is based on powers of 10, meaning a G2 storm is 10 times stronger than a G1 storm and so on.
The storm in May that produced auroras across much of California and as far south as Florida was a G5 storm. On Monday, some people in Northern California reported seeing another aurora.
As of Wednesday afternoon, NOAA's aurora forecast dashboard showed a possible view line extending into southern Oregon for Thursday night.
Bryan Brasher with NOAA said auroras typically happen up to 250 miles above the surface of the Earth and view lines could extend up to 600 or 800 miles away.
"Aurora can weaken and intensify very quickly and there are times where they could be seen south of the view line, but that line is a best guess on the limit to which people could expect to have a chance to see them," he said ahead of the event.
Aurora sightings are also reported on the NASA-funded science project Aurorasaurus. You can sign up to get alerts from the Aurorasaurus.