Solar activity was moderate. Region 225 (N17E23) produced an M2/1n flare with associated Type-II and Type-IV radio sweeps at 16/1115 UTC. No CME was evident in LASCO imagery following this event. Other activity included numerous C-class flares from several regions, notably from 226 (S28E12), 227 (N07W07), and 229 (N18E37). All of today's flare producing regions have shown some growth in size and/or magnetic complexity. No new regions were numbered today.

Solar activity is expected to be low to moderate for the next three days. The regions discussed in section 1A above all appear to be possible sources for isolated M-class flare activity.

The geomagnetic field was predominantly quiet, with some isolated unsettled periods. A gradual reduction in high speed stream effects was apparent in data from the ACE satellite over the course of the day.

The geomagnetic field is expected to be quiet to unsettled for the next 24-36 hours. Recurrent high speed stream effects are expected to develop on day two, and affect geomagnetic activity with isolated active and possible minor storm conditions, particularly on day three of the forecast period.

  觀測的       16 Dec 203
  預測的   17 Dec-19 Dec  200/200/195
  90天平均值        16 Dec 165

  觀測的 Afr/Ap 15 Dec  005/009
  估算值     Afr/Ap 16 Dec  005/008
  預測的    Afr/Ap 17 Dec-19 Dec  010/010-015/015-020/035