Both NOAA’s Space Weather Prediction Center and the U.K. Met’s Space Weather Operations Centre have issued a G2-Moderate geomagnetic storm watch for April 2, due to the presence of a negative polarity coronal hole high speed stream (or CH HSS) facing the Earth. While this isn’t a full coronal mass ejection, coronal holes cause an increase in the speed and volume of the charged particles coming from the sun, and can affect Earth in similar, albeit more moderate, ways.

“Early on Day 3 (2nd April), a high-speed stream from coronal hole 67 is expected to reach Earth,” according to the Met Office’s release. Coronal holes are cool, dark areas on the Sun that exhibit an opening in the star’s magnetic field, hence the increase in charged particles coming from them. Coronal hole 67 was present on the Sun’s surface on it’s last rotation last month, and caused a G3-Strong geomagnetic storm.

NOAA warns that the storm could cause fluctuations in the power grid, radio interference, interference to the GPS system, and may disorient migrating birds. The particle stream could also produce auroras as far south as New York to Wisconsin to Washington state.