Solar activity increased to high levels this period. Region 338 (N18W32) produced an M5/1n flare at 23/0106Z. Type II (513 km/s) and Type IV radio sweeps, and a 380 sfu tenflare were associated with this event. A partial halo CME was also detected on LASCO imagery. An M2/1f flare also occurred in this region at 23/1556Z. This complex region continues to develop in both size and magnetic complexity. Region 339 (N16W84) was quite active as it approaches the west limb. It produced several C-class flares, the largest being a C5 flare at 23/1213Z. No significant changes were observed in the remaining active regions. New Region 343 (N06E60) was numbered today.

Solar activity is expected to be at moderate levels. Region 338 maintains potential for further M-class activity.

The geomagnetic field ranged from quiet to active levels with isolated minor storm periods at high latitudes. Elevated solar wind speeds near 500 km/s are responsible for the disturbed periods. The greater than 2 MeV electrons at geosynchronous orbit reached high levels again today.

The geomagnetic field is expected to be at unsettled to minor storm levels. Ongoing high speed coronal hole flow will likely be enhanced by transient flow over the next three days. Weak impact from the April 22, M2 flare and CME are possible on day one. There is a higher probability for CME impacts on days two and three from the M5 and associated CME that occurred early this period.

  觀測的       23 Apr 133
  預測的   24 Apr-26 Apr  135/140/145
  90天平均值        23 Apr 126

  觀測的 Afr/Ap 22 Apr  013/022
  估算值     Afr/Ap 23 Apr  015/020
  預測的    Afr/Ap 24 Apr-26 Apr  020/020-020/020-015/015