:Product: 20050117RSGA.txt :Issued: 2005 Jan 17 2200 UTC # Prepared jointly by the U.S. Dept. of Commerce, NOAA, # Space Environment Center and the U.S. Air Force. # Joint USAF/NOAA Report of Solar and Geophysical Activity SDF Number 017 Issued at 2200Z on 17 Jan 2005 IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: Solar activity was high. Region 720 (N13W30) continued to produce flare activity with the largest being an X3/2f at 17/0952 UTC. This flare was associated with a complex full-halo CME directed mostly towards the northwest. Although this region remains large and magnetically complex some restructuring of the sunspots was apparent following this flare. New Region 723 (N06E77) is rotating around the east limb. IB. Solar Activity Forecast: Solar activity is expected to remain at high to very high levels. Region 720 could produce yet another major solar event. IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic field ranged from quiet to severe storm levels. Solar wind conditions observed by the NASA ACE spacecraft show a fairly complex onset of activity which may suggest the arrival of a solar wind structure from combined CMEs expected from previous major flares on 15 January. The proton event at greater than 10 MeV that began on 16/0210 UTC remains in progress. The latest X3 flare discussed in Part IA has increased the current peak flux to 5040 pfu observed at 17/1750 UTC. A proton event at greater than 100 MeV also resulted from the X3 flare, beginning at 17/1215 UTC and with a current peak flux of 28 pfu observed at 17/1700 UTC. The greater than 2 MeV electron flux observed by the GOES spacecraft, as well as the solar wind parameters observed by the ACE SWEPAM instruments, have been rendered temporarily unusable due to the energetic proton event. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to continue at major to severe storm levels. Another CME arrival is expected late on 18 January, or possibly early on 19 January, due to today's X3 flare, which should keep geomagnetic activity levels elevated. The current proton events are expected to remain in progress. III. Event Probabilities 18 Jan-20 Jan Class M 90/90/90 Class X 30/30/30 Proton 99/99/99 PCAF in progress IV. Penticton 10.7 cm Flux Observed 17 Jan 138 Predicted 18 Jan-20 Jan 135/130/120 90 Day Mean 17 Jan 107 V. Geomagnetic A Indices Observed Afr/Ap 16 Jan 010/012 Estimated Afr/Ap 17 Jan 060/080 Predicted Afr/Ap 18 Jan-20 Jan 060/080-050/050-030/030 VI. Geomagnetic Activity Probabilities 18 Jan-20 Jan A. Middle Latitudes Active 15/20/50 Minor storm 50/50/30 Major-severe storm 35/30/10 B. High Latitudes Active 10/10/50 Minor storm 50/50/30 Major-severe storm 40/40/20