Solar activity was at moderate levels due to an M3 x-ray event observed on the west limb at 04/1145Z. This event originated from the west limb spot group complex consisting of Regions 1280 (N13W91) and 1286 (N20W75). Close proximity to the limb made precise analysis of the flare location difficult. Associated with the M3 event was a west limb CME, first observed in LASCO C2 imagery at 04/1212Z. A plane-of-sky speed was estimated at about 400 km/s. Preceding this event was another west limb CME, first observed in LASCO C2 imagery at 04/0912Z. A plane-of-sky speed was estimated at about 150 km/s. Analysis of the potential geoeffectiveness of these CMEs is ongoing. Numerous C-class flares were also observed during the period from this area of the west limb. Region 1287 (S32E51) produced a C1 x-ray event early in the period at 03/2212Z. This region showed minor growth in area while the remaining regions on the disk indicated a slight decay in area coupled with loss of spots.

Solar activity is expected to be low for the next three days (05 - 07 September). A chance for additional M-class activity exists through 06 September.

The geomagnetic field was at quiet to unsettled levels. Observations from the ACE spacecraft indicated wind speeds varied predominately between 350 to 400 km/s. The Bz component of the interplanetary magnetic field did not vary much beyond +/- 5 nT during the period.

The geomagnetic field is expected to be at quiet to unsettled levels for day one (05 September) due to continuing effects from a coronal hole high speed stream (CH HSS). By days two and three (06 - 07 September), the field is expected to be at mostly quiet levels as the CH HSS moves out of a geoeffective position.

  Pozorováno       04 Sep 119
  Předpovězeno   05 Sep-07 Sep  120/115/105
  90 denní průměr        04 Sep 098

  Pozorováno Afr/Ap 03 Sep  009/013
  Odhadovaný     Afr/Ap 04 Sep  007/008
  Předpovězeno    Afr/Ap 05 Sep-07 Sep  005/008-005/005-005/005