:Product: 1223RSGA.txt :Issued: 2015 Dec 23 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 357 Issued at 2200Z on 23 Dec 2015 IA. Analysis of Solar Active Regions and Activity from 22/2100Z to 23/2100Z: Solar activity has been at moderate levels for the past 24 hours. The largest solar event of the period was a M4 event observed at 23/0040Z from Region 2473 (S23E49). There are currently 4 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares and a slight chance for an X-class flare on days one, two, and three (24 Dec, 25 Dec, 26 Dec). IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 527 km/s at 23/1343Z. Total IMF reached 10 nT at 23/1304Z. The maximum southward component of Bz reached -7 nT at 23/1252Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3889 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and two (24 Dec, 25 Dec) and quiet to unsettled levels on day three (26 Dec). III. Event probabilities 24 Dec-26 Dec Class M 50/50/50 Class X 10/10/10 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 23 Dec 134 Predicted 24 Dec-26 Dec 135/130/125 90 Day Mean 23 Dec 110 V. Geomagnetic A Indices Observed Afr/Ap 22 Dec 008/010 Estimated Afr/Ap 23 Dec 007/009 Predicted Afr/Ap 24 Dec-26 Dec 010/012-012/014-010/010 VI. Geomagnetic Activity Probabilities 24 Dec-26 Dec A. Middle Latitudes Active 25/20/15 Minor Storm 05/05/05 Major-severe storm 01/01/01 B. High Latitudes Active 15/15/20 Minor Storm 30/30/25 Major-severe storm 30/25/20