Solar activity was high. Two highly impulsive M-class flares occurred during the period. Both were optically uncorrelated. The first was an M6 flare at 20/0603 UTC, with an accompanying Type II radio sweep (1200 km/s) and a 360 sfu 10 cm radio burst. EIT imagery shows that this event originated over the southwestern limb and was probably from Region 9455 (S17W90+). An impressive coronal mass ejection (CME) in conjunction with the flare can be seen on images from the LASCO/SOHO spacecraft. The CME appears to be non earth-directed. An M1 flare with an accompanying Type II radio sweep (1088 km/s) was detected at 20/0920 UTC. This event was most likely a backside event from the same region as the previously described M6 event. Region 9463 (N09E46) nearly doubled in size and spot count overnight and also developed into a more complex sunspot group classification (14 spot, Eko-Beta). Region 9465 (S08E63) was numbered as it rotated onto the disk, already showing a 4 spot Dao-Beta sunspot classification.

Solar activity is expected to be low to moderate. Regions 9461 (N22E10) and 9463 are both capable of producing isolated M-class events.

The geomagnetic field was at quiet to unsettled levels. The greater than 10 MeV proton flux at geosynchronous orbit became enhanced following today's M6 flare, but did not reach event criteria. The greater than 2 MeV electron flux at geosynchronous orbit reached moderate levels during the period.

The geomagnetic field is expected to be mostly quiet to unsettled for the first two days of the forecast period. Isolated active conditions may occur on the third day due to a potentially favorably positioned coronal hole and the subsequent high speed stream impacting earth. The greater than 2 MeV electron flux and greater than 10 MeV proton flux at geosynchronous orbit should continue to be at elevated levels for the first half of the period and then can expected to return to near background levels.

  Observé       20 May 142
  Prévisionnel   21 May-23 May  140/140/140
  Moyenne des 90 derniers jours        20 May 168

  Observé Afr/Ap 19 May  010/012
  Estimé     Afr/Ap 20 May  008/012
  Prévisionnel    Afr/Ap 21 May-23 May  008/012-008/012-015/015