GEOMAGNETIC STORM FORECAST: Earth is about to be hit by a double-stream of solar wind. The two streams are flowing from holes in the sun's atmosphere, shown here in an extreme ultraviolet image from NASA's Solar Dynamics Observatory: [link to spaceweather.com]

Solar wind flowing from the right coronal hole is expected to arrive on Aug. 28. A more potent stream of solar wind flowing from the left coronal hole should reach us on Sept. 1-2.

G1-class geomagnetic storms are possible on both dates, although Sept. 1-2 is more likely to experience storm conditions. Why? Because the coronal hole on the left is spewing a faster stream of gas than the one on the right: ~650 km/s vs. ~500 km/s respectively.

[link to spaceweather.com]