Solar activity was very low. No flares occurred during the past 24 hours.

Solar activity is expected to be very low.

The geomagnetic field was initially quiet. However, a weak shock was seen at ACE at 1054Z, followed by an increase in magnetic field strength and density as well as a small increase in velocity. There were some extended intervals of southward Bz and as a result there was a period of minor to major storm level activity from 1500-1800Z. Conditions declined to active to minor storm levels for remainder of the period (1800-2100Z). Although the observations are not yet conclusive the disturbance appears to be from a transient structure in the solar wind, rather than from a recurrent structure. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels during the past 24 hours.

The geomagnetic field is expected to be unsettled with occasional active periods for the first day (28 September) due to the anticipated onset of a high speed stream from a coronal hole. Activity should strengthen on the second day (29 September) to predominantly active levels with a chance for minor storm periods at high latitudes. Conditions should decline to predominantly unsettled levels on the third day (30 September).

  Observed       27 Sep 067
  Predicted   28 Sep-30 Sep  067/067/067
  90 Day Mean        27 Sep 069

  Observed Afr/Ap 26 Sep  002/003
  Estimated     Afr/Ap 27 Sep  010/015
  Predicted    Afr/Ap 28 Sep-30 Sep  010/015-020/025-010/012