Space Weather Forecast - Discussion

Issued: 2025 Dec 20 0030 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center and processed by SpaceWeatherLive.com

Solar activity

24 h Summary

Solar activity briefly reached moderate levels due to an impulsive M1.0 at 19/1558 UTC that originated from a region just beyond the southeast limb. Regions 4308 (N08, L=136) and 4310 (N03, L=177) decayed to plage, while new spots were observed near N23E44 but remain unnumbered at this time given their age and lack of growth since emergence. The remaining active regions were either stable or showing signs of decay. No Earth-directed CMEs were observed in available coronagraph imagery.

Forecast

Solar activity is expected to be at low levels with occasional C-class flares through 22 Dec.

Energetic Particles

24 h Summary

The greater than 2 MeV electron flux reached high levels with a peak flux of 3,240 pfu at 19/1810 UTC. The greater than 10 MeV proton flux was steady at background levels.

Forecast

The greater than 2 MeV electron flux is expected to reach high levels through 21 Dec before decreasing to normal to moderate levels on 22 Dec with the arrival of a corotating interaction region ahead of faster solar wind. The greater than 10 MeV proton flux is expected to persist at background levels through 22 Dec given the lack of complex, energetic active regions currently inhabiting the visible solar disk.

Solar Wind

24 h Summary

The solar wind environment reflected waning negative polarity CH HSS influences. Total field decreased from 5 nT to 2-4 nT while the Bz component was benign at rougly +/- 5 nT. Solar wind speeds peaked near 670 km/s before gradually declining to about 500 km/s. Phi was predominantly negative, but began undergoing oscillations into the positive sector late in the period.

Forecast

The solar wind environment is expected to remain mildly enhanced over 20 Dec as negative polarity CH HSS influences diminish. Background conditions are then expected to prevail on 21 Dec. An enhanced regime is anticipated to return on 22 Dec due to recurrent, positive polarity CH HSS influences.

Geospace

24 h Summary

Geomagnetic field activity was at quiet levels.

Forecast

Geomagnetic field activity is expected to be at quiet levels with a chance for isolated periods on 20 Dec as CH HSS effects continue to diminish with quiet conditions then continuing on into 21 Dec. G1 (Minor) geomagnetic storming is likely on 22 Dec due to recurrent, positive polarity CH HSS effects.