This has been a dream week for aurora chasers. There have has been G2 storming four of the last five days. SWPC has predicted that it will continue today and tomorrow as well. A G2 watch is up for today (September 11, 2015), and tomorrow. This storm watch is posted in anticipation of the arrival of a coronal hole high speed stream. Here is the watch graphic from SWPC:
For timing, the expected peak will come overnight in Europe and just as evening is approaching on the East coast. You can see in the NLN 3-day forecast clock the storm is expected to start with G2 storming, then taper to G1 for the next 6-12 hours. In addition to this being perfectly timed for a Friday night – most of us don’t have work the next day – it is falling when the moon is nearly new, so it should be very dark.
The source of this storm is a coronal hole that was pointed directly at Earth on Sept 8. The size and shape of the hold suggest this should be a good show.
As always with these watches, there is a chance we might not get any aurora from this storm. We saw a period of high solar wind speed earlier in the day, and that may have been the entire storm. Space weather scientists and forecasters don’t have enough data coming from satellites and ground based observations to really make the models 100% accurate. If you go out tonight, and there aren’t any aurora, don’t fret, enjoy the stars and know there will be more opportunities.