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Product: Daily Forecast of Geomagnetic Activity
Issued: 2025 September 05 04:13UTC
Prepared by the Athens Space Weather Forecasting Center
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I. Solar activity
--Current Status
Solar Flux (10.7cm) measured on 04.09.2025 at 23:00 UTC was 172 sfu.
The background X-Ray flux is at the class C1.5 level.
One M1-class solar flare were produced on September 04.
No obviously Earth directed CMEs were observed in available LASCO imagery on September 02-September 04.
A coronal hole (CH1315) at southern hemisphere will rotate into an Earth facing position on September 02-07.

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 535 Km/s on September 04 at 14:20 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 -5 nT on September 04 at 14:20 UT during the last 24 hours.
The geomagnetic field was at quiet to unsettled levels during the last 24 hours.
The Kp index now is at quiet levels with Kp=2.

IV. 3-day Geomagnetic Activity Forecast
The geomagnetic field is expected to be at quiet to minor storm (G1) levels on September 05-06 due to the effect of the coronal hole (CH1315) high speed stream and at quiet to active levels on September 07.

Date	Ap index forecast	Geomagnetic Activity level	
05.09.2025	18	Quiet to Minor storm	
06.09.2025	15	Quiet to Minor storm	
07.09.2025	18	Quiet to Active	

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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
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