A high speed solar wind stream from a large, recurrent, trans-equatorial coronal hole is anticipated to arrive at the weekend (27th-28th September). On the previous rotation this coronal hole caused peaks of STORM G2 geomagnetic conditions (see NOAA space weather scales for more details about these storm levels).
Geomagnetic activity is again likely to reach a maximum of STORM G2 from Friday through to Sunday as we are closer to the autumn equinox and the coronal hole remains broadly similar in scope to the previous rotation. We cannot rule out a small chance of an isolated period of STORM G3. Some peak activity is likely to occur with the initial arrival of the high speed stream with the elevated solar wind likely to remain geoeffective for around 48 hours before starting to subside.
Assuming clear, dark skies there is an increased chance of seeing the aurora on Friday and Saturday evening into the night. Those in Scotland, northern England and Northern Ireland may have the best chance, if the weather is favourable and if geomagnetic activity levels are as anticipated.
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