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Product: Daily Forecast of Geomagnetic Activity
Issued: 2023 September 15 10:09UTC
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 14.09.2023 at 20:00 UTC was 145 sfu.
The background X-Ray flux is at the class C1.0 level.
The geomagnetic field was at quiet to active levels on September 14.
Three M-class solar flares were produced on September 14 and the biggest was the M2.5. The M2.5 class solar flare erupted on September 14 at 21:26 UT (peak time) from AR3429 and a radioblackout (R1) was observed.
A CME was observed in SOHO LASCO C2, C3, and STEREO A COR2 on September 14 at 07:24 UT.
This CME could reach Earth between on September 16 at 13:58 UT and on September 17 at 00:37 UT according to EAM predictions.
No obviously Earth directed CMEs were observed in available LASCO imagery.
The Kp index now is at quiet levels with Kp=1.

2. Solar Wind Geomagnetic Activity
Solar Wind speed from ACE: 480 km/s.
Solar Wind speed from STEREO A: 400 km/s.
Solar Wind speed from STEREO B: - km/s.
The southward component Bz is: 6 nT north.

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

4. Coronal Holes
An equatorial coronal hole (CH1172) was Earth facing on September 11-13.

5. Geophysical Activity Forecast
The geomagnetic field is expected to be at quiet to unsettled levels on September 15-16 and at quiet to minor storm (G1) levels on September 17 due to the effect of the CME observed on September 14.

   Date      Estimated Ap index      Expected geom. storm
2023.09.15           12                        -
2023.09.16           08                        -
2023.09.17           20                        G1

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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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