Solar activity was low. Today's activity consisted of three, low-level C-class flares from Region 410 (S12E28). This group showed emerging flux and has developed some magnetic complexity. However, the field intensity and sunspot area are still relatively small. Region 409 (N16E27) continues to be the largest group on the disk but showed overall decay and some simplification. Region 409 was quiet and stable during the past 24 hours. Two new regions were assigned today: Region 412 (N16E19) and Region 413 (N18E49).

Solar activity is expected to be predominantly low. There continues to be a chance, however, for an isolated M-class event over the next three days. Region 409 is the most likely source for energetic flares, but Region 410 might also produce an M-flare if the current growth trend continues.

The geomagnetic field ranged from active to major storm levels. An initially active field attained storm levels after 0300 UTC and continued at storm levels through 1500 UTC. Conditions returned to active levels from 1500 UTC through the end of the period. The increase in activity was associated with a slight increase in solar wind speed (600 to 650 km/s) and a noticeable increase in total magnetic field in the solar wind (ranging from 10 to 15 nT). The solar wind signatures are consistent for the most part with a high speed solar wind stream originating from a favorably positioned coronal hole.

The geomagnetic field is expected to be mostly active with minor storm periods during the next 24 hours as the current disturbance persists. A decrease to unsettled to active is expected on the second and third days as the high speed solar wind should gradually decline.

  觀測的       16 Jul 133
  預測的   17 Jul-19 Jul  130/130/125
  90天平均值        16 Jul 126

  觀測的 Afr/Ap 15 Jul  015/027
  估算值     Afr/Ap 16 Jul  025/045
  預測的    Afr/Ap 17 Jul-19 Jul  020/030-015/020-015/015