NOAA Space Weather Bulletin August 4, 2011
NOAA Region 1261, very active over the past few days, produced the third of a sequence of Coronal Mass Ejections (CMEs) and Solar Radio Blackout Events early today. The net effect of that activity is convergent CMEs expected to disturb the geomagnetic field in the early hours, Universal Time (UTC) of August 5. G3 (Strong) Geomagnetic Storm conditions are likely as well as a distinct chance of S2 (Moderate) Solar Radiation Storm levels being surpassed.

From SpaceWeather.com….
Moving at an estimated speed of 1950 km/s, this CME is expected to sweep up two earlier CMEs already en route. Analysts at the GSFC Space Weather Lab say the combined cloud should reach Earth on August 5th at 13:55 UT (9:55 AM EDT) plus or minus 7 hours: “The impact on Earth is likely to be major. The estimated maximum geomagnetic activity index level Kp is 7 (Kp ranges from 0 – 9). The flanks of the CME may also impact STEREO A, Mars and Mercury/MESSENGER.” High-latitude sky watchers should be alert for auroras. Please visit SpaceWeather.com for full details and latest news!

If we happen to have clear(ish) skies Friday night, Aug. 5, it might be worth stepping outside well after twilight and taking a look. You never know, we might get auroras!