Check out this huge coronal hole on the sun as it could be a chance to reach geomagnetic storm levels on May 19-20 2017.
Indeed, during the last rotation, this coronal hole caused solar wind speeds up to 750km/s and a lot of geomagnetic storming.
The NOAA SWPC has a moderate G2 geomagnetic storm watch in effect for tomorrow evening (UTC) which could very well be possible considering the history of this coronal hole.
Well worth to keep your eyes on the solar wind data starting tomorrow evening to see how this is going to develop.
Especially for our southern hemisphere sky watchers this could be a very interesting events as their nights are becoming longer and longer.
The NOAA SWPC had a moderate G2 geomagnetic storm watch in effect during the past few days but we unfortunately haven’t even reached the minor G1 geomagnetic storm level.