Solar activity was at low levels due to single, low-level C-class events from Regions 1461 (N10W89), 1466 (N12W51), 1467 (N12E18), 1469 (S19E14) and new Region 1470 (S17E61). New Region 1471 (S23E70) was also numbered during the period. A 16 degree filament eruption was observed in SDO/AIA 304 imagery at 28/1045Z. During the period of the eruption, the SE to NW oriented filament was centered near S32W33. LASCO/C2 imagery observed an associated slow-moving, non-Earth directed CME lifting off the SW limb at 28/1224Z.

Solar activity is expected to be low with a slight chance for M-class activity for the next three days (29 April - 01 May).

The geomagnetic field was at quiet to unsettled levels with an isolated high latitude active period between 28/0900 - 1200Z. Through the period, ACE solar wind velocities steadily decreased from about 490 km/s to near 420km/s while the Bz component of the interplanetary magnetic field was variable between +/-4 nT. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels throughout the period.

The geomagnetic field is expected to be at predominately quiet levels for days one and two (29 - 30 April). By day three (01 May), quiet to unsettled levels, with isolated active periods, are expected as a coronal hole high speed stream moves into a geoeffective position.

  觀測的       28 Apr 121
  預測的   29 Apr-01 May  125/120/120
  90天平均值        28 Apr 112

  觀測的 Afr/Ap 27 Apr  007/008
  估算值     Afr/Ap 28 Apr  005/005
  預測的    Afr/Ap 29 Apr-01 May  004/005-004/005-007/008