*********************************************************************** Product: Daily Forecast of Geomagnetic Activity Issued: 2018 September 21 06:38UTC Prepared by the Athens Space Weather Forecasting Center *********************************************************************** 1. Solar activity Solar activity was decreasing stable during the past 24 hours. Solar Flux (10.7 cm) measured on 20.09.2018 at 20:00 UTC was 67 sfu. The background X-Ray flux is at the class A2 level. The geomagnetic field was at very quiet levels on September 20. No obviously Earth directed CMEs were observed in available LASCO imagery. The Kp index now is at quiet levels with Kp=1. 2. Solar Wind Geomagnetic Activity Solar Wind speed from ACE: 335 km/s. Solar Wind speed from STEREO A: 440 km/s. Solar Wind speed from STEREO B: --- km/s. The southward component Bz is: 2 nT north. 3. Solar Energetic Particle Events Protons and electrons are quiet. 4. Coronal Holes An extension of the northern polar coronal hole (CH886) it will be in Earth facing position on September 17-19 but it is not expected to be geoeffective due to mid-latitude position. A new equatorial coronal hole (CH887) is expected to be in Earth facing position on September 19-21. 5. Geophysical Activity Forecast The geomagnetic field is expected to be at very quiet levels on September 21 and at quiet to unsettled levels, with a chance for active intervals, on September 22. Quiet to active levels, with a chance for minor storm intervals, expected for September 23 due to CH887 effects. Date Estimated Ap index Expected geom. storm 2018.09.21 02 - 2018.09.22 09 - 2018.09.23 17 - *************************************************************************** Athens Space Weather Forecasting Center Physics Department, National & Kapodistrian University of Athens Athens Neutron Monitor Station A.NE.MO.S Tel.: +30 210 727 6901 email: spaceweather@phys.uoa.gr URL: http://spaceweather.phys.uoa.gr ***************************************************************************