*********************************************************************** Product: Daily Forecast of Geomagnetic Activity Issued: 2018 July 21 04:55UTC Prepared by the Athens Space Weather Forecasting Center *********************************************************************** 1. Solar activity Solar activity was increasing during the past 24 hours. Solar Flux (10.7 cm) measured on 20.07.2018 at 20:00 UTC was 71 sfu. The background X-Ray flux is at the class A2 level. The geomagnetic field was at quiet to unsettled levels on July 20. No obviously Earth directed CMEs were observed in available LASCO imagery. The Kp index now is at almost quiet levels with Kp=2. 2. Solar Wind Geomagnetic Activity Solar Wind speed from ACE: 490 km/s. Solar Wind speed from STEREO A: 610 km/s. Solar Wind speed from STEREO B: --- km/s. The southward component Bz is: 1 nT north. 3. Solar Energetic Particle Events Protons and electrons are quiet. 4. Coronal Holes An extension of the northern polar coronal hole (CH875) was in Earth facing position on July 15-16 with minor effects. A new coronal hole (CH876) on the southern hemisphere of the visible solar disk will be in Earth facing position on July 21-22. 5. Geophysical Activity Forecast The geomagnetic field is expected to be at quiet to unsettled levels on July 21-22 due to CH875 effects and at quiet levels on July 23. Date Estimated Ap index Expected geom. storm 2018.07.21 06 - 2018.07.22 05 - 2018.07.23 04 - *************************************************************************** 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 ***************************************************************************