Solar activity decreased to low levels. There were two large, magnetically complex sunspot groups on the visible disk: Region 9727 (S22W88) and Region 9733 (N14W23). Region 9727 produced isolated subflares while crossing the west limb. It retained at least a moderate degree of magnetic complexity as it rotated out of view with mixed polarities in its trailer spots. Region 9733 remained the most active region on the disk as it produced occasional subflares, some of which reached C-class. This region has showed a gradual decrease in area since 13 December. However, opposite-polarity magnetic flux has gradually emerged within its northernmost spots during the last two days where a possible delta magnetic configuration may reside. The remaining active regions showed minor changes during the period. New Region 9742 (N09E73) rotated into view during the period.

Solar activity is expected to be at moderate to high levels. Isolated low-level M-class flares are expected. There will also be a chance for a major flare from Region 9733. Region 9727 could also produce a major flare during the first day of the period as it completes its west limb passage.

Geomagnetic field activity was at quiet to unsettled levels.

Unsettled to minor storm conditions may occur on 16 - 17 December due to a possible CME passage (associated with the X6/3b flare of 13 December). Activity is expected to decrease to quiet to unsettled levels during the latter half of the forecast period. There will be a chance for a proton flare from Region 9733.

  Havaittu       15 Dec 218
  Ennusteet   16 Dec-18 Dec  205/195/190
  90 vuorokauden keskiarvo        15 Dec 218

  Havaittu Afr/Ap 14 Dec  004/004
  Arvioitu     Afr/Ap 15 Dec  013/012
  Ennusteet    Afr/Ap 16 Dec-18 Dec  015/020-015/015-010/010