Northern Lights Now – The trend of busy space weather over the last two months continues tomorrow with a new geomagnetic storm watch issued for January 6, 2016. The watch, which means it’s possible space weather conditions may produce aurora, is due to an expected increase in ambient solar wind speeds. The source of the higher wind speed is a large transequitorial coronal hole that was pointed directly at Earth on January 3.
The current official forecast is only calling for a single 3-hour period of KP=5 for this storm, but there’s a prolonged period of KP=4 before and after the predicted peak period. That’s an unusually short period of activity for a coronal hole, and it may turn out to be an underestimate. It’s possible that at any point in the 15 hours before and after the predicted peak KP values could cross above minor storm thresholds. If any small CMEs are carried along the wind stream their impact can be magnified. Here is the SWPC forecast as of midnight GMT on Jan 5 as visualized by the NLN auroracast infographic:
This is the second rotation for this coronal hole. On the last rotation it produced solar wind speeds around 650 km/s and two short periods of KP= 5.0 – 5.33. The coronal hole actually looks to have a slightly more defined signature in this rotation. Read NLN’s post about the last rotation here