Topline
The National Oceanic and Atmospheric Administration issued a severe geomagnetic storm watch for Saturday and, as a result, much of the northern part of the country may be able to see the northern lights in an “unusual and potentially historic event.”
The National Oceanic and Atmospheric Administration said the “severe level” of aurora expected ... [+]
Key Facts
Geomagnetic storms happen when material erupts from the sun’s atmosphere, creating disturbances to the Earth’s magnetic fields and occasionally triggering “spectacular displays of aurora,” also known as the northern lights.
Scientists said Friday night’s aurora may be visible as far south as Alabama and Northern California, and conditions could continue through the weekend.
The geomagnetic activity of the aurora is expected to be an eight on a scale of nine on Friday night, and a five Saturday night, according to the Space Weather Prediction Center, with the line of visibility passing through Oregon, Colorado, Illinois, Pennsylvania and more.
Clear and dark skies make the best viewing conditions for the aurora, and the best time to see it is “three or four hours around midnight,” according to the Geophysical Institute at the University of Alaska Fairbanks.
The National Weather Service is forecasting fairly low cloud cover—meaning the sky will likely be clear—for much of the northern U.S., except for Michigan and Wisconsin, around 12 a.m. on Saturday.
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Surprising Fact
The Severe Geomagnetic Storm Watch is the first of its kind since January 2005.
Key Background
The northern lights are happening at all times, but are not always visible. They are most frequently seen near the North Pole, and the best time of year to see them is between September and April. Scientists are able to predict when auroras will be visible by examining solar winds, though the predictions are made with fairly low confidence. According to CBS News, aurora forecasts are about as reliable as weather forecasts were in the 1950s.
What To Watch For
If the weekend’s geomagnetic storm brings any damage. G4 storms are the second-strongest kind of geomagnetic storm and are able to damage satellites and cause “widespread voltage problems” and issues with the electric power grid, radio and navigation, according to NOAA. Space weather forecaster at NOAA Shawn Dahl told the Associated Press he wouldn’t want to speculate on the damage that could occur, but said “the severe level is pretty extraordinary. It's a very rare event to happen.”
