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Product: Daily Forecast of Geomagnetic Activity
Issued: 2023 April 23 08:21UTC
Prepared by the Athens Space Weather Forecasting Center
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1. Solar activity
Solar activity was decreasing stable during the past 24 hours.
Solar Flux (10.7 cm) measured on 22.04.2023 at 20:00 UTC was 141 sfu.
The background X-Ray flux is at the class B9.1 level.
The geomagnetic field was at quiet to unsettled levels on April 22.
A Halo CME was visible in SOHO LASCO C2/C3 and STEREO A COR2 imagery. The source is a filament eruption starting around on April 21 at17:30 UT from AR3283. This CME could reach Earth between on April 23 at 11:52 UT and on April 24 at 06:15 UT according to EAM predictions.
No obviously Earth directed CMEs were observed in available LASCO imagery.
The Kp index now is quiet levels with Kp=2.

2. Solar Wind Geomagnetic Activity
Solar Wind speed from ACE: 365 km/s.
Solar Wind speed from STEREO A: 400 km/s.
Solar Wind speed from STEREO B: - km/s.
The southward component Bz is: 7 nT south.

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

4. Coronal Holes
An equatorial coronal hole (CH1141)  rotated across the central meridian on April 19. A large recurrent equatorial coronal hole (CH1142) will likely become Earth facing on April 23-25.

5. Geophysical Activity Forecast
The geomagnetic field is expected to be at quiet to minor storm (G1) levels on April 23, at unsettled to moderate storm (G2) levels on April 24 due to the effects of coronal hole high speed stream and CME observed on April 21 and at quiet to active levels on April 25.

   Date      Estimated Ap index      Expected geom. storm
2023.04.23           15                        G1
2023.04.24           35                        G1-G2
2023.04.25           15                        -

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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
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