A “moderate to strong” solar storm is on its way to Earth Friday. An erupting sunspot has unleashed three solar flares in as many days, the third particularly potent.

SpaceWeather.com offers this detail: “The latest blast at 0357 UT on August 4th [11:57 p.m. EDT August 3] registered M9.3 on the Richter Scale of Flares, almost crossing the threshold into X-territory (X-flares are the most powerful kind).”

This flare has produced a cloud of charged particles known as a coronal mass ejection (CME) moving at a trail blazing speed of over four million miles per hour (according to SpaceWeather.com). SpaceWeather.com reports it will “sweep up” the two prior CMEs and reach Earth around 9:55 a.m. EDT plus or minus seven hours. [two videos here]

NOAA’s Space Weather Prediction Center describes it this way: “real anticipation for the first of what may be three convergent shocks to slam the geomagnetic field in the next twelve hours . .. Two impacts are expected G2 (Moderate) to G3 (Strong) Geomagnetic Storming on August 5, and potentially elevated protons to the S2 (Moderate) Solar Radiation Storm condition”

In short, this solar activity could upset electronic equipment, particularly in space. NASA tweeted that auroras may be viewable as far south as Pennsylvania Friday night.

For much more on this topic, see Steve Tracton’s primer on space weather and impact scales..