Fingers crossed for clear conditions Friday night as the potential grows for widespread auroras across Canada.
Widespread auroras are possible across most of Canada and a large swath of the U.S. on Friday night as forecasters expect a potent geomagnetic storm to kick off the weekend.
This event ranks as a ‘severe’ G4 on the scale used to measure the intensity of geomagnetic storms. The scale ranges from from G1 (minor) on the low end to G5 (extreme) on the high end.
Forecasters with NOAA’s Space Weather Prediction Center (SWPC) issued a geomagnetic storm watch ahead of the event, saying on Friday that “watches at this level are very rare.” This is the first G4-level watch issued by the agency since January 2005.
Expected to arrive late Friday night
Our weekend aurora potential is the result of three separate coronal mass ejections (CMEs) merging into one as they approach Earth. A CME is a burst of plasma and magnetic field released from the Sun’s blazing hot outer atmosphere.
The charged particles of a CME can filter into Earth’s upper atmosphere around the magnetic poles, ionizing gasses like oxygen and hydrogen to create the phenomenal display of dancing colours we see as the northern lights.
The SWPC expects the geomagnetic storm to peak late Friday night into very early Saturday morning, with the strongest aurora potential around 11:00 p.m. to 5:00 a.m. Eastern Time, or 8:00 p.m. to 02:00 a.m. Pacific Time.
Any change in this geomagnetic storm’s arrival time would affect Canada’s viewing. An earlier arrival might favour Europe over Canada, while a later arrival might allow for more widespread viewing opportunities across the country.
A geomagnetic storm of this caliber could produce visible auroras far south of the border, as well. NOAA says that the northern lights could be visible as far south as Alabama and northern California if the event peaks at the right time.
Clouds may obscure the view for some regions
Sunlight is only part of the equation when it comes to spotting the northern lights. Where might clouds obscure the view?
The best opportunity for clear skies exists on the western Prairies and into British Columbia. Folks around Regina, Saskatoon, Edmonton, and Calgary may catch a good show if this geomagnetic storm lives up to its full potential. Clear skies throughout B.C. may offer a good view if the northern lights arrive after sunset and twilight.
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