G1 (Minor) Geomagnetic Storm WATCH Issued for 20-21 Sep 2015
published: Tuesday, September 22, 2015 18:06 UTC UTC
Isolated periods of minor geomagnetic storm conditions are likely on 20 Sep due to the influence of a positive polarity coronal hole high speed stream (CH HSS). G1 storms are likely again early on 21 Sep due to continued CH HSS influence in addition to the anticipated arrival of a CME from 18 Sep.