:Product: 1221RSGA.txt :Issued: 2025 Dec 21 2200 UTC # Prepared jointly by the U.S. Dept. of Commerce, NOAA, # Space Weather Prediction Center and the U.S. Air Force. # Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 355 Issued at 2200Z on 21 Dec 2025 IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity has been at moderate levels for the past 24 hours. There are currently 5 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares on days one, two, and three (22 Dec, 23 Dec, 24 Dec). IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field has been at unsettled to minor storm levels for the past 24 hours. Solar wind speed reached a peak of 723 km/s at 21/2028Z. Total IMF reached 15 nT at 21/1128Z. The maximum southward component of Bz reached -11 nT at 21/0544Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 2257 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to minor storm levels on day one (22 Dec), quiet to minor storm levels on day two (23 Dec) and unsettled to active levels on day three (24 Dec). III. Event probabilities 22 Dec-24 Dec Class M 25/25/30 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 21 Dec 124 Predicted 22 Dec-24 Dec 130/135/140 90 Day Mean 21 Dec 148 V. Geomagnetic A Indices Observed Afr/Ap 20 Dec 004/006 Estimated Afr/Ap 21 Dec 016/021 Predicted Afr/Ap 22 Dec-24 Dec 019/028-015/022-010/020 VI. Geomagnetic Activity Probabilities 22 Dec-24 Dec A. Middle Latitudes Active 35/35/30 Minor Storm 30/30/15 Major-severe storm 10/10/01 B. High Latitudes Active 10/10/15 Minor Storm 20/20/30 Major-severe storm 65/65/40