Solar activity was low. Five C-class x-ray events were observed in the past 24 hours. Region 1224 (N20W56) produced a C3 event at 30/0252Z which was accompanied by a faint, but potentially geoeffective, CME seen in STEREO-B COR2 imagery at 30/1209Z with a plane-of-sky speed estimate of 610 km/s. Region 1224 grew slightly and ended the period as a Dso type group with Beta-Gamma magnetic characteristics. Region 1227 (S18E54) was also associated with CME activity. At 30/1101Z, this region produced a C2/Sn flare accompanied by a Type II sweep (1697 km/s) and CME observed in LASCO C2 imagery (estimated speed 420 km/s). Earlier in the period, Region 1227 produced a C8/Sf that peaked at 29/2120Z. GOES-15 x-ray signatures indicated this event began at 29/2011Z with northward surging evident by 29/2035Z. At 29/2124Z, LASCO C2 imagery observed a potentially geoeffective CME with an estimated plane-of-sky velocity of 1576 km/s. Associated with this flare were Type II (1548 km/s), Type IV and 10 cm (520 sfu) radio signatures. Region 1227 ended the period as a Dsi type group with Beta-Gamma magnetic characteristics. Region 1226 (S21E42) produced a C3/Sf flare at 30/0549Z and a C7/Sn flare at 30/0605Z. This region ended the period as a Dki type group with Beta-Gamma magnetic characteristics. New Region 1229 (N16E38) was numbered and classified as a Cao type group with Beta magnetic characteristics.

Solar activity is expected to be low with a chance for M-class events for the next three days (31 May - 02 Jun).

The geomagnetic field ranged from quiet to active levels. A coronal hole high speed stream continued to cause disturbed geomagnetic conditions. Some signs of weakening were evident at the ACE spacecraft as solar wind speed decreased from near 700 km/s to about 600 km/s, the total interplanetary magnetic field strength decreased to less than 5 nT and the average Bz component was approximately 0 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 quiet to unsettled on days 1 and 2 (31 May - 1 Jun) as the coronal hole high speed stream wanes. Conditions are expected to remain unsettled with a chance for active periods on day 3 (02 Jun) due to the potential influence from the 29 and 30 May CMEs.

  Observé       30 May 112
  Prévisionnel   31 May-02 Jun  115/115/115
  Moyenne des 90 derniers jours        30 May 108

  Observé Afr/Ap 29 May  017/032
  Estimé     Afr/Ap 30 May  007/018
  Prévisionnel    Afr/Ap 31 May-02 Jun  010/015-007/010-010/012