PRESTO FROM SIDC - RWC BELGIUM Wed May 23 2012, 1231 UT

Catania sunspot group 39 (NOAA AR 1484) produced a C1.2 flare peaking at 00:27 UT today. More C-class flares can be expected from this group, as well as from recently emerged Catania sunspot group 47 (NOAA AR 1488).
The post-shock solar wind flow was followed by a fast solar wind stream (with the speed reaching 700 km/s) from a small low-latitude coronal hole in the southern hemisphere. Due to high interplanetary magnetic field (IMF) magnitude (that reached 15 nT), active geomagnetic conditions (K = 4) were reported by Dourbes and IZMIRAN and minor storm conditions (K = 5) were reported by NOAA. Currently the solar wind speed is still elevated (around 620 km/s), but the IMF magnitude decreased to average values (around 4 nT). We therefore expect quiet geomagnetic conditions.