NOAA warns of M5.7 Solar Flare effects after May 10 eruption

A solar flare of M5.7 strength erupted from the sun on May 10 and peaked at 9:39 a.m. EDT. The flare came from sunspot region AR4436 and launched a coronal mass ejection that could reach Earth around early May 13.

The eruption triggered radio blackouts over the Atlantic Ocean. NOAA's Space Weather Prediction Center and the U.K. Met Office said the expanding plume may brush past Earth and, if it does, could bring minor G1 geomagnetic storm conditions.

AR4436 and AR4432

AR4436 is rotating into Earth's strike zone on the sun's northeastern limb, and both AR4436 and AR4432 are continuing to evolve. NOAA's Space Weather Prediction Center and the U.K. Met Office warned that additional M flares and possibly X-class eruptions could occur over the coming days.

Solar flares are ranked A, B, C, M and X, with X the most powerful category, and each step represents a tenfold increase in energy output. The May 10 event reached M5.7 strength, while the latest coronal mass ejection is not expected to produce anything close to the May 10, 2024 extreme G5 storm that sent auroras as far south as southern Florida and Mexico.

Early May 13

If the plume brushes past Earth, aurora displays could strengthen across the northern U.S. and the U.K. The practical effect for readers is a short window in which radio conditions, geomagnetic activity and high-latitude sky visibility may all change at once.

That makes early May 13 the period to watch, with the current flare already showing how quickly a single eruption can interrupt radio use and set up a brief geomagnetic response days later.