:Product: 1218RSGA.txt :Issued: 2025 Dec 18 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 352 Issued at 2200Z on 18 Dec 2025 IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity has been at low 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 slight chance for an M-class flare on days one, two, and three (19 Dec, 20 Dec, 21 Dec). IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been at quiet to minor storm levels for the past 24 hours. Solar wind speed reached a peak of 723 km/s at 18/0659Z. Total IMF reached 7 nT at 17/2227Z. The maximum southward component of Bz reached -7 nT at 17/2232Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 2693 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one and two (19 Dec, 20 Dec) and quiet levels on day three (21 Dec). III. Event probabilities 19 Dec-21 Dec Class M 15/15/15 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 18 Dec 116 Predicted 19 Dec-21 Dec 115/110/110 90 Day Mean 18 Dec 149 V. Geomagnetic A Indices Observed Afr/Ap 17 Dec 010/018 Estimated Afr/Ap 18 Dec 014/018 Predicted Afr/Ap 19 Dec-21 Dec 009/010-008/008-005/005 VI. Geomagnetic Activity Probabilities 19 Dec-21 Dec A. Middle Latitudes Active 25/20/10 Minor Storm 10/05/01 Major-severe storm 01/01/01 B. High Latitudes Active 15/15/15 Minor Storm 25/25/20 Major-severe storm 35/25/10