STRONG GEOMAGNETIC STORM WATCH: NOAA has upgraded their forecast for the next geomagnetic storm from G2 (Moderate) to G3 (Strong). The storm is expected to begin late on May 7th, when an incoming CME strikes, intensifying on May 8th as Earth passes through the CME's magnetized wake. Aurora alerts: SMS Text. 

THE INCOMING CME: A three-day outburst of M-class solar flares on May 3rd, 4th and 5th, hurled so many CMEs into space that analysts had trouble sorting them out. NOAA has determined that at least one is heading for Earth. Click to play their animated forecast model:

If this model is correct, the CME will hit Earth's magnetic field on May 7th around 2100 UT. The impact could spark geomagnetic storms ranging in intensity from minor (G1) to moderate (G2) and maybe even strong (G3). An unrelated stream of solar wind might also contribute to the geomagnetic activity. During G3-class storms, auroras have been sighted in the USA as far south as Illinois and Oregon. Aurora alerts: SMS Text. 

Update: This NOAA model replaces an earlier one which had the CME arriving on May 8th at 1800 UT. The difference between the two models gives a sense of the uncertainty in the CME's predicted arrival time. Aurora chasers should be prepared for an impact on either May 7th or 8th.