*********************************************************************** Product: Daily Forecast of Geomagnetic Activity Issued: 2025 October 26 09:01UTC Prepared by the Athens Space Weather Forecasting Center ***********************************************************************
I. Solar activity --Current Status Solar Flux (10.7cm) measured on 25.10.2025 at 23:00 UTC was 127 sfu. The background X-Ray flux is at the class B5.5 level. No obviously Earth directed CMEs were observed in available LASCO imagery on October 23-25. A coronal hole (CH1324) at southern hemisphere will likely become Earth facing on October 26-27. A small equatorial coronal hole (CH1325) rotated across the central meridian on October 21. An equatorial coronal hole (CH1326) will likely rotate across the central meridian on October 27.
II. Solar Energetic Particle Events Protons and electrons fluxes are quiet.
III. Interplanetary and Geomagnetic conditions The solar wind speed measured by ACE satellite reached the max value 480 Km/s on October 25 at 12:45 UT during the last 24 hours. The solar wind speed from STEREO A was detected 400 Km/s during the last 24 hours. The vertical component of IMF Bz reached the max value -4 nT on October 26 at 05:05 UT during the last 24 hours. The geomagnetic field was at quiet to active levels during the last 24 hours. The Kp index now is at quiet levels with Kp=1.
IV. 3-day Geomagnetic Activity Forecast The geomagnetic field is expected to be at quiet to unsettled levels on October 26 and at quiet to active levels on October 27-28.
Date
Ap index forecast
Geomagnetic Activity level
26.10.2025
10
Quiet to Unsettled
27.10.2025
12
Quiet to Active
28.10.2025
15
Quiet to Active
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