Coronal hole faces Earth

Friday, 21 April 2017 09:58 UTC

A coronal hole is facing Earth. Enhanced solar wind could arrive in ~3 days - Follow live on https://t.co/T1Jkf6i4Cb pic.twitter.com/Y1KQAgY2fD

— SpaceWeatherLive (@_SpaceWeather_) April 20, 2017

This is starting to become a famous coronal hole as this coronal hole has been around for well over a year in all kinds of shapes and sizes. It often caused some decent geomagnetic storming when it faced Earth. During the last rotation it caused moderate G2 geomagnetic storm conditions (Kp6) on 27 March.

Lets compare how this coronal looks like right now and how it looked like during the previous rotation. It changed a little bit, becoming smaller in the southern most portion but arguably increasing in size where it matters most, at the latitudes near the solar equator

That is excellent news as that means we should expect similar solar wind conditions on this rotation as we had during the previous rotation. Based on these facts we conclude that it is not out of the question that we will again experience moderate G2 geomagnetic storm conditions once the solar wind stream arrives. The solar wind stream should take about two to three days to cover the distance between the Sun and the Earth so the solar wind stream is likely to arrive on 23 April. We issue a moderate G2 geomagnetic storm watch for this coming Sunday, 23 April 2017. It is almost new moon as well so excessive moonlight should not be an issue when aurora watching!