Detailed Information

Solar Activity

Solar activity in the past 24 hours was active.

Twelve C-class flares occurred in the past 24 hours. The strongest was a C9.7 flare, which peaked at 15:46 UT from NOAA 14294. Three type III solar radio bursts and one CME were recorded during this period. The CME was west-directed, had a median velocity of 496 km/s and an angular width of 24°. No east-directed CMEs were detected. The latest SDO/HMI Intensitygram data show seven active regions (NOAA 14294, 14296, 14299, 14304, 14305, 14306, and 14307), while the latest BBSO H-alpha data reveal three plages (NOAA 14295, 14300, and 14303) on the solar disk. Farside data show two active regions expected to return from the solar eastern limb in the next 72 hours.

Based on today's conditions,

• solar activity for 12 December, 04:00 UT–13 December, 03:59 UT is predicted to be major flare;
• solar activity for 13 December, 04:00 UT–14 December, 03:59 UT is predicted to be eruptive;
• solar activity for 14 December, 04:00 UT–15 December, 03:59 UT is predicted to be eruptive.

Geomagnetic Activity

The geomagnetic activity was on moderate storm level for the last 24 hours.

The solar wind speed increased from 363 km/s to 500 km/s, while the north-south component of the interplanetary magnetic field decreased  from 7.2 nT to -16.5 nT. There was one geoeffective coronal hole at the northeast, while other at the eastern equator was not geoeffective. CME on 11 December at 13:25 UT was mainly erupted toward the west with a speed of 496 km/s and an angular width of 24°.The CME was geoeffective but is likely to have no impact until the next 3 days.

• Major storm level geomagnetic activity is expected for the next 24 hours;
• Minor storm level geomagnetic activity is expected for 13 December, 04:00 UT–14 December, 03:59 UT;
• Active level geomagnetic activity is expected for 14 December, 04:00 UT–15 December, 03:59 UT.

Ionospheric Activity

Evaluation of the ionospheric activity, foF2 value, the increase in the fmin value, Spread-F, and the Sporadic E-Layer cannot be reported due to problems at the CADI station. However the S4 index values and TEC index can not be evaluated for the last 24 hours.

The ionosphere activity on 12 December 2025, 04:00 UT - 13 December 2025, 03:59 UT is predicted to be minor . 

The ionosphere activity on 13 December 2025, 04:00 UT - 14 December 2025, 03:59 UT is predicted to be strong. 

The ionosphere activity on 14 December 2025, 04:00 UT - 15 December 2025, 03:59 UT is predicted to be minor.

Navigation

The error of the single frequency GPS positioning for the next 24 hours was on normal level, based on ionospheric scintilation and TEC variation. 
Based on ionospheric scintilation and TEC variation, the probability of error positioning on 12 December 2025, 04:00 UT - 13 December 2025, 03:59 UT is predicted at a normal level. 

Based on ionospheric scintilation and TEC variation, the probability of error positioning on 13 December 2025, 04:00 UT – 14 December 2025, 03:59 UT is predicted at a normal level.

Based on ionospheric scintilation and TEC variation, the probability of error positioning on 14 December 2025, 04:00 UT - 15 December 2025, 03:59 UT is predicted at a normal level.

HF Radio Communication

MUF depression and Short Wave Fadeout (SWF) cannot be evaluated for the last 24 hours.

The MUF depression for December 12th, 04:00 UT - December 13th, 03:59 UT is predicted at a moderate level, due to previous geomagnetic activity.

The MUF depression for December 13th, 04:00 UT - December 14th, 03:59 UT is predicted at a severe level, due to previous geomagnetic activity.

The MUF depression for December 14th, 04:00 UT - December 15th, 03:59 UT is predicted at an moderate level, due to previous geomagnetic activity

The SWF for December 12th, 04:00 UT - December 13th, 03:59 UT is predicted at a strong level due to the prediction of a solar flare.

The SWF for December 13th, 04:00 UT - December 14th, 03:59 UT is predicted at a quiet level due to the prediction of a solar flare.

The SWF for December 14th, 04:00 UT - December 15th, 03:59 UT is predicted at a quiet level due to the prediction of a solar flare.

Satellites

The electron flux was at a low level for the last 24 hours.

• A high level of electron flux is expected for the next 24 hours;
• A low level of electron flux is expected for 13 December, 04:00 UT–14 December, 03:59 UT;
• A low level of electron flux is expected for 14 December, 04:00 UT–15 December, 03:59 UT.

The flux of high-energy protons in the past 24 hours was quiet.

Based on today's condition,

• the flux of high-energy proton for 12 December, 04:00 UT–13 December, 03:59 UT is predicted to be quiet;
• the flux of high-energy proton for 13 December, 04:00 UT–14 December, 03:59 UT is predicted to be quiet;
• the flux of high-energy proton for 14 December, 04:00 UT–15 December, 03:59 UT is predicted to be quiet.