=================================== Weekly Space Weather Highlights =================================== Highlights of Solar and Geomagnetic Activity 15 - 21 May 2017 Solar activity was very low throughout the reporting period. Region 2659 (N14, L=038, class/area=Dao/040 on 21 May 2017) was the most complex region; however, it has produced no significant flare activity. No Earth-directed CMEs were observed in available coronagraph imagery. No proton events were observed at geosynchronous orbit. The greater than 2 MeV electron flux at geosynchronous orbit ranged from normal to high levels, with a peak flux of 13,000 pfu at 21/1710 UTC. Normal levels were observed on 15 May and moderate levels were observed on 16-19 May. In response to a negative polarity CH HSS, high levels were observed on 20-21 May. Geomagnetic field activity was at quiet to active levels. Quiet to active levels were observed on 15 May. Conditions decreased to quiet to unsettled levels on 16-17 May under nominal solar wind conditions. A SSBC produced quiet to active levels on 18 May and quiet to unsettled levels on 19 May. The subsequent onset of a negative polarity CH HSS, with peak observed winds between 700-750 km/s, produced unsettled to active conditions on 20 May and quiet to unsettled levels on 21 May. Forecast of Solar and Geomagnetic Activity 22 May - 17 June 2017 Solar activity is expected to be very low with a slight chance for C-class flare activity throughout the outlook period. No proton events are expected at geosynchronous orbit. The greater than 2 MeV electron flux at geosynchronous orbit is expected to range from normal to very high levels. Moderate levels are likely on 01-10 Jun and 12-15 Jun; high levels are likely on 22 May, 27-31 May, and 16-17 Jun; very high levels are likely on 23-26 May. Elevated levels of electrons are in response to multiple, recurrent, CH HSSs. The remainder of the outlook period is likely to observe normal background levels. Geomagnetic field activity is expected to be at quiet to G1 (Minor) storm levels. Active conditions are likely on 22 May with unsettled conditions likely on 23-24 May due to the waning effects of a negative polarity CH HSS. Quiet conditions are then likely to prevail from 25 May-09 Jun under a nominal solar wind regime. An increase to active conditions is likely on 10-11 Jun from a positive polarity CH HSS. Quiet conditions are again likely on 12-13 Jun. A SSBC is expected to cause unsettled conditions on 14 Jun. A subsequent negative polarity CH HSS is likely to cause active conditions on 15 Jun, G1 (Minor) conditions on 16 Jun, then active conditions as the CH HSS wanes on 17 Jun.