*********************************************************************** Product: Daily Forecast of Geomagnetic Activity Issued: 2018 August 17 07:17UTC 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 16.08.2018 at 20:00 UTC was 68 sfu. The background X-Ray flux is at the class A2 level. The geomagnetic field was at almost quiet to active levels on August 16. No obviously Earth directed CMEs were observed in available LASCO imagery. The Kp index now is at active levels with Kp=4. 2. Solar Wind Geomagnetic Activity Solar Wind speed from ACE: 495 km/s. Solar Wind speed from STEREO A: 470 km/s. Solar Wind speed from STEREO B: --- km/s. The southward component Bz is: 3 nT north. 3. Solar Energetic Particle Events Protons and electrons are quiet. 4. Coronal Holes A coronal hole (CH880) which is an extension of the northern polar coronal hole was in Earth facing position on August 11-12. A high speed stream of solar wind from CH880 reached Earth on the first half of August 15. A new coronal hole (CH881) is expected to be in Earth facing position on August 16-18. 5. Geophysical Activity Forecast The geomagnetic field is expected to be at quiet to active levels on August 17 due to CH880 effects and at quiet levels on August 18-19. Date Estimated Ap index Expected geom. storm 2018.08.17 10 - 2018.08.18 06 - 2018.08.19 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 ***************************************************************************