At 0631 UTC on April 20 the Australian Space Forecast Centre issued a Geomagnetic Disturbance Warning.
“Earth is currently under the influence of a high-speed stream from a negative polarity equatorial coronal hole. Geomagnetic activity at Quiet to Active levels is expected and at times may reach up to Minor Storm levels if there are notable southward Bz periods.
INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL HOLE HIGH SPEED WIND STREAM FROM 20-21 APRIL 2018