Sun fires powerful M6.9 solar flare and CME toward Earth — could it boost northern lights chances this week?

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Today (Aug. 25), the sun unleashed a powerful M6.9 solar flare from a restless Earth-facing sunspot, hurling a coronal mass ejection (CME) into space — and Earth could potentially be in the firing line.

The M6.98 solar flare erupted from the active sunspot region 4513 and peaked at 6 a.m. EDT (1000 GMT), according to SpaceWeatherLive. 4513 has been particularly active over the last 24 hours, firing off a barrage of solar flares including five powerful M-class eruptions.

Solar flares are ranked by strength into five classes — A, B, C, M and X — with each class 10 times more powerful than the one before it. M-class flares are the second-strongest category, sitting just below the most powerful X-class eruptions.

The eruption also triggered a moderate (R2) radio blackout across the sunlit side of Earth, affecting high-frequency radio communications over parts of Africa, Europe and the Arctic.

CME incoming

Now, all eyes are on the CME launched during today's M6.9 eruption.

Early modelling suggests Earth could receive a glancing blow from the CME on Friday (Aug. 28). According to aurora chaser Jure Atanackov, NASA's model predicts the CME could reach Earth at around 6-7 a.m. EDT (1000-1100 GMT), with an uncertainty of around seven hours.

Though Atanackov described the CME as slow-moving and said he isn't expecting much from the glancing encounter, there's another piece of the space weather puzzle that could make things interesting for aurora chasers.

According to the Solar Influences Data Analysis Center (SIDC), a high-speed stream of solar wind from a positive-polarity coronal hole is expected to begin influencing Earth from Aug. 27. SIDC forecasts unsettled to active geomagnetic conditions, with a chance of minor storm levels as the fast solar wind arrives.

If the glancing CME arrival coincides with the high-speed solar wind stream, the two influences could work together to ramp up geomagnetic activity and potentially enhance aurora activity.

How much of an impact the CME ultimately has will depend on its exact arrival time and, crucially, the orientation of its magnetic field when it reaches Earth. A strong southward magnetic field would interact more effectively with Earth's magnetic field, increasing the chances of stronger geomagnetic activity.

We'll be keeping a close eye on the latest models and space weather forecasts as Friday approaches and will update this story as more information becomes available.