The sun has been acting up this week, and normally that would produce auroral displays bright enough to see in Washington state.
But this isn’t a normal week: Western skies have been obscured by wildfire smoke, and although westerly winds are expected to push out a lot of that smoke overnight in the Seattle area, it’s debatable whether northern lights will be visible.
One solar flare, rated as a moderate M5 on the National Oceanic and Atmospheric Administration’s space weather scale, generated a wave of electrically charged particles that is now sweeping past Earth. That produced the conditions for a strong geomagnetic storm.
The most noticeable effect would be heightened auroras, and NOAA’s Space Weather Prediction Center said northern lights could be visible along the northern tier of the United States.
The Watch for 6 and 7 Sep was upgraded to G3 (Strong) due to predicted CME arrival and reactions. Check https://t.co/dimAHhR0NF for more pic.twitter.com/ggyPqo33iD
— NOAA Space Weather (@NWSSWPC) September 5, 2017
But in the Pacific Northwest, the delicate greenish glow of the aurora is likely to be overwhelmed by the dull reddish glow of the nearly full moon, shining through an obscuring haze of wildfire smoke:
GOES-R satellite shows extensive smoke over WA and even off the coast. Wide coverage suggests #smoke may not improve much until Thurs. #wawx pic.twitter.com/316rp9wogk
— NWS Seattle (@NWSSeattle) September 6, 2017
This morning's full moon descending into a smoky horizon. Now you see it…now you don't. #wawx pic.twitter.com/mKR6z70ifc
— NWS Seattle (@NWSSeattle) September 6, 2017
There might be another chance for auroras in the days ahead: Two more solar flares erupted early today, at 2:10 a.m. and 5;02 a.m. PT. The second one registered as an X9.3 blast, which makes it the strongest flare observed in more than a decade. The electromagnetic pulses were powerful enough to cause widespread radio blackouts.
Early indications suggest that the resulting coronal mass ejection will deal Earth’s magnetosphere a glancing blow, producing moderate auroral displays on Thursday night. But it’s not known exactly how clear our skies will get over the next few days. Although the wildfire smoke is expected to clear out, the forecast calls for the more usual kind of clouds.
The best advice is to watch the weather forecast, keep an eye on the auroral forecast – and, as always, watch the skies.
Here’s our standard list of aurora resources:
- Aurora Forecast from the University of Alaska at Fairbanks.
- Space Weather Prediction Center, with 30-minute and 3-day forecasts.
- SWPC’s Planetary K-Index chart shows expectations for geomagnetic levels.
- The Space Weather Enthusiasts Dashboard is a gold mine for geeks. And be sure to check in on SWPC’s Facebook page.
- Soft Serve News pulls together the SWPC predictions on one webpage and provides the bottom line for the next 45 minutes.
- SpaceWeather.com rounds up all the news about auroras, eclipses, meteors and other sky extravaganzas – with an aurora photo gallery as well.
- National Weather Service forecast page includes a sky-cover forecast.
- Astronomer-educator Alice Enevoldsen’s Seattle guide to aurora viewing.
This report has been updated with forecasts from SpaceWeatherLive.com.
