:Product: 1217RSGA.txt :Issued: 2015 Dec 17 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 351 Issued at 2200Z on 17 Dec 2015 IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C1 event observed at 17/1235Z from Region 2470 (N15E18). There are currently 3 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is likely to be low with a slight chance for an M-class flare on days one, two, and three (18 Dec, 19 Dec, 20 Dec). IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 553 km/s at 17/1836Z. Total IMF reached 7 nT at 17/1448Z. The maximum southward component of Bz reached -7 nT at 17/1448Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 603 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to minor storm levels on day one (18 Dec), active to major storm levels on day two (19 Dec) and quiet to active levels on day three (20 Dec). III. Event probabilities 18 Dec-20 Dec Class M 15/15/15 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 17 Dec 118 Predicted 18 Dec-20 Dec 120/125/125 90 Day Mean 17 Dec 109 V. Geomagnetic A Indices Observed Afr/Ap 16 Dec 005/005 Estimated Afr/Ap 17 Dec 007/009 Predicted Afr/Ap 18 Dec-20 Dec 011/016-030/042-014/018 VI. Geomagnetic Activity Probabilities 18 Dec-20 Dec A. Middle Latitudes Active 35/35/30 Minor Storm 20/35/10 Major-severe storm 05/15/01 B. High Latitudes Active 15/05/15 Minor Storm 25/20/35 Major-severe storm 50/70/40