Northern Lights Now – A large polar-connected coronal hole will bring high speed solar wind to Earth starting August 4th and SWPC has posted a G2 geomagnetic storm watch. The watch means it is possible that aurora activity as measured by KP may reach 5.67 during the August 4th UTC day (from 8pm EST on 8/3 through 8pm EST on 8/4). The watch period extends into August 5th at a slightly lower activity level with G1 storming predicted.
The coronal hole responsible for this activity is large. It extends from the polar region to the Southern Hemisphere of the Sun:
Earth is expected to travel through the area of high speed solar winds sometime on Friday. Any disturbances carried on the wind stream with a negative oriented Bz could make for strong aurora activity. Keep any eye on the solar wind data, there should be a period of increased activity in Bt and Bz before the actual arrival.
The current timing and forecast for this storm calls for the G1 and G2 storming late on the 4th followed by G1 storming through midday on the 5th as winds subside. As always, these forecasts can be +/-12 hours, so the best bet is to keep an eye on the data or the Northern Lights Now Twitter feed, to know when it is best to go out.
The Moon is waxing gibbous – which means it will be visible and bright in the evening and set after midnight. The best aurora viewing times will be in the wee hours after the Moon sets.