Space Weather Report
Space Weather Report
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Product: Daily Forecast of Geomagnetic Activity
Issued: 2025 December 20 06:59UTC
Prepared by the Athens Space Weather Forecasting Center
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I. Solar activity
--Current Status
Solar Flux (10.7cm) measured on 19.12.2025 at 23:00 UTC was 118 sfu.
The background X-Ray flux is at the class B8.0 level.
AR4307 erupted on December 19 at 15:58 UT peak time producing a M1.0-class solar flare and a radio blackout of category R1.
No obviously Earth directed CMEs were observed in available LASCO imagery on December 17-19.
An equatorial coronal hole (CH1335) rotated across the central meridian on December 14-15.
An equatorial coronal hole (CH1336) could become Earth facing on December 19-21.
II. Solar Energetic Particle Events
Protons fluxes are quiet.
The greater than 2 MeV electron flux at geosynchronous orbit reached minor storm levels on December 19.
III. Interplanetary and Geomagnetic conditions
The solar wind speed measured by ACE satellite reached the max value 583 Km/s on December 19 at 07:05 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 -3 nT on December 19 at 19:00 UT during the last 24 hours.
The geomagnetic field was at quiet 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 levels on December 20-21 and at quiet to minor storm (G1) levels on December 22 due to the effect of the recurrent coronal hole high speed stream.
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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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Product: Daily Forecast of Geomagnetic Activity
Issued: 2025 December 20 06:59UTC
Prepared by the Athens Space Weather Forecasting Center
***********************************************************************
I. Solar activity
--Current Status
Solar Flux (10.7cm) measured on 19.12.2025 at 23:00 UTC was 118 sfu.
The background X-Ray flux is at the class B8.0 level.
AR4307 erupted on December 19 at 15:58 UT peak time producing a M1.0-class solar flare and a radio blackout of category R1.
No obviously Earth directed CMEs were observed in available LASCO imagery on December 17-19.
An equatorial coronal hole (CH1335) rotated across the central meridian on December 14-15.
An equatorial coronal hole (CH1336) could become Earth facing on December 19-21.
II. Solar Energetic Particle Events
Protons fluxes are quiet.
The greater than 2 MeV electron flux at geosynchronous orbit reached minor storm levels on December 19.
III. Interplanetary and Geomagnetic conditions
The solar wind speed measured by ACE satellite reached the max value 583 Km/s on December 19 at 07:05 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 -3 nT on December 19 at 19:00 UT during the last 24 hours.
The geomagnetic field was at quiet 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 levels on December 20-21 and at quiet to minor storm (G1) levels on December 22 due to the effect of the recurrent coronal hole high speed stream.
| Date | Ap index forecast | Geomagnetic Activity level |
|---|---|---|
| 20.12.2025 | 05 | Quiet |
| 21.12.2025 | 05 | Quiet |
| 22.12.2025 | 20 | Quiet to MinorStorm (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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