G1 storm watch issued by NOAA

Monday, 25 June 2018 17:53 UTC

The NOAA SWPC expects a coronal hole solar wind stream to impact our planet at the previously mentioned date and expects solar wind speeds of about 700km/s at our planet.

This forecast is based on STEREO Ahead data but after a closer look from us we have to temper the expectations a bit. This coronal hole has been slowly closing up and there is not so much left of it now that it faces Earth. You can see this clearly on this image (see the tweet below) that we made where we compare the coronal hole with how it looks like today, and how it looked like back on 30 May when the coronal hole faced Earth during the previous solar rotation.

The SWPC posted a G1 storm watch for 27 June due to an expected coronal hole solar wind stream.

However, this coronal hole has almost disappeared and there is little left now that it faces Earth. We do not expect solar wind conditions that could cause a G1 storm. pic.twitter.com/X0veQQG8PR

— SpaceWeatherLive (@_SpaceWeather_) June 25, 2018

While a weak increase in the solar wind conditions at Earth is possible, it is very unlikely to be enough for minor G1 geomagnetic storm conditions. The coronal hole has dissolved significantly and it is unlikely to produce the solar wind speeds that the NOAA SWPC expects according to our analysis.