*********************************************************************** Product: Daily Forecast of Geomagnetic Activity Issued: 2018 December 28 07:11UTC 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 27.12.2018 at 20:00 UTC was 69 sfu. The background X-Ray flux is at the class A2 level. The geomagnetic field was at very quiet to unsettled levels on December 27. 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: 545 km/s. Solar Wind speed from STEREO A: 350 km/s. Solar Wind speed from STEREO B: --- km/s. The southward component Bz is: 3 nT south. 3. Solar Energetic Particle Events Protons and electrons are quiet. 4. Coronal Holes A new equatorial coronal hole (CH901) was in Earth facing position on December 23-25. A high speed stream of solar wind reached Earth on the last hours of December 27. 5. Geophysical Activity Forecast The geomagnetic field is expected to be at quiet to active levels, with a chance for minor storm intervals, on December 28-30 due to CH901 effects. Date Estimated Ap index Expected geom. storm 2018.12.28 15 - 2018.12.29 12 - 2018.12.30 08 - *************************************************************************** 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 ***************************************************************************