Product: Daily Forecast of Geomagnetic Activity
Issued: 2017 April 23 09:01UTC
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 22.04.2017 at 20:00 UTC was 84 sfu.
The background X-Ray flux is at the class A9 level.
The geomagnetic field was at active to moderate storm (G2) levels on April 22.
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: 690 km/s.
Solar Wind speed from STEREO A: 410 km/s.
Solar Wind speed from STEREO B: --- km/s.
The southward component Bz is: 2 nT south.

3. Solar Energetic Particle Events
Protons and electrons are quiet.

4. Coronal Holes
A coronal hole (CH802) was in Earth facing position on April 20-22.
A high speed stream from this CH should reach Earth between the last hours of April 22 and the first hours of April 23.

5. Geophysical Activity Forecast
The geomagnetic field is expected to be at unsettled to minor storm levels on April 23-24 and at quiet to unsettled levels on April 25.

Date Estimated Ap index Expected geom. storm
2017.04.23 26 G1
2017.04.24 22 G1
2017.04.25 12 -

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