:Product: 1218RSGA.txt :Issued: 2024 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 353 Issued at 2200Z on 18 Dec 2024 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. The largest solar event of the period was a C8 event observed at 18/0734Z. There are currently 6 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 (19 Dec, 20 Dec, 21 Dec). IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 604 km/s at 18/2048Z. Total IMF reached 13 nT at 17/2100Z. The maximum southward component of Bz reached -9 nT at 17/2316Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 338 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on days one, two, and three (19 Dec, 20 Dec, 21 Dec). III. Event probabilities 19 Dec-21 Dec Class M 40/45/45 Class X 05/05/05 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 18 Dec 174 Predicted 19 Dec-21 Dec 175/185/190 90 Day Mean 18 Dec 200 V. Geomagnetic A Indices Observed Afr/Ap 17 Dec 020/025 Estimated Afr/Ap 18 Dec 011/014 Predicted Afr/Ap 19 Dec-21 Dec 005/005-005/005-006/005 VI. Geomagnetic Activity Probabilities 19 Dec-21 Dec A. Middle Latitudes Active 10/10/10 Minor Storm 05/05/05 Major-severe storm 01/01/01 B. High Latitudes Active 15/15/15 Minor Storm 20/20/20 Major-severe storm 15/15/15