Forecasting the weather here on earth can be tough. It’s even harder to predict space weather and how solar storms may, or may not interact with the earth’s magnetosphere.
It turns out the Coronal Mass Ejection (CME) racing toward earth Wednesday night was oriented in a way that failed to trigger northern lights. That produced a weaker magnetic field according to NOAA’s Space Weather Prediction Center.
The 7 December, 2020, CME arrived in line with the forecast, as an interplanetary shock was detected at DSCOVR at 10/0132 UTC (09 Dec, 8:32pm ET). The magnetic strength of this storm was less than the peak potential that could have initiated a G3 (Strong) geomagnetic storm as it arrived at Earth. Therefore, SWPC forecasters are downgrading to G1 (Minor) storm Watches for the remainder of today (10 Dec) and tomorrow (11 Dec).
Why didn't the CME cause a storm? Every CME brings with it some magnetic field from the sun. If that magnetic field points south, it opens cracks in Earth's magnetic field, allowing solar wind to flow inside and fuel auroras. On the other hand, if the CME's magnetic field points north, it seals cracks in Earth's magnetic field, blocking the solar wind and quenching storms.
This CME brought a storm-killing north magnetic field. So, even though the velocity of the solar wind in the CME's wake flirted with a high value of 600 km/s, it was ineffective in causing geomagnetic storms and auroras.
Solar Cycle 25
Wednesday night’s projected storm may have fizzled. But "Solar Cycle 25" is just starting. That could bring an uptick in solar storms in the next few years.
Again, spaceweather.com explains its significance.
Sept. 15, 2020: Solar Cycle 25 is officially underway. NASA and NOAA made the announcement during a media teleconference earlier today. According to an international panel of experts, the sunspot number hit rock bottom in Dec. 2019, bringing an end to old Solar Cycle 24. Since then, sunspot counts have been slowly increasing, heralding new Solar Cycle 25.
“How quickly solar activity rises is an indicator on how strong the next solar cycle will be,” says Doug Biesecker of NOAA’s Space Weather Prediction Center, co-chair of the Solar Cycle 25 Prediction Panel. “Although we’ve seen a steady increase in sunspot activity this year, it is slow.”
The panel believes that new Solar Cycle 25 will be a weak one, peaking in 2025 at levels similar to old Solar Cycle 24. If their prediction is correct, Solar Cycle 25 (like Solar Cycle 24 before it) will be one of the weakest since record-keeping began in 1755.
“While we are not predicting a particularly active Solar Cycle 25, violent eruptions from the sun can occur at any time,” warns Biesecker. Indeed, even Solar Minimum can produce a superstorm, so Solar Cycle 25 should not be taken lightly despite the panel’s low expectations. Radio blackouts, power outages and severe geomagnetic storms are possible in the years ahead.
So we got skunked Wednesday night. But the chances for solar storms that will deliver vivid northern lights in the coming years will increase.
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