:Product: 20011230RSGA.txt :Issued: 2001 Dec 30 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 364 Issued at 2200Z on 30 Dec 2001 IA. Analysis of Solar Active Regions and Activity from 29/2100Z to 30/2100Z: Solar activity has been moderate. Early in the period, newly numbered Region 9767 (S23E73) produced an M2/1f event at 29/2256 UTC. This region is the likely source of the X-class flare and CME activity of 28 December, and has now rotated into view. The region appears to be of significant size and magnetic complexity, but is current location near the east limb prevents a full analysis of it's characteristics. Other activity during the same period included a long duration M1 x-ray enhancement during 29/1950-2355 UTC, with an associated west limb CME evident in LASCO imagery, though appearing to lack any significant earth-directed component. Other regions on the visible disk were mostly quiescent, with a few minor C-class events observed. An additional new region was also numbered today, Region 9766 (N05E62). IB. Solar Activity Forecast: Solar activity is expected to continue at predominantly moderate levels, with a fair chance for isolated major flare events during the next three days. IIA. Geophysical Activity Summary 29/2100Z to 30/2100Z: Geomagnetic field activity has been quiet to active. Most of the period was dominated by ongoing effects from yesterday's shock passage, with an extended period of southward IMF producing active conditions during 30/0300-0900 UTC. Late in the period, an additional shock passage was observed at the ACE satellite at 30/1932 UTC, followed by a sudden impulse of 27 nT observed at Boulder at 30/2010 UTC. This event is presumed to be an early arrival of effects from the powerful X-class event of 28 December. The greater than 10 MeV proton flux at geosynchronous orbit has fluctuated near the event threshold value of 10 pfu for most of the day, though now appears to be undergoing some enhancement due to the recent shock passage. As a result of near-threshold activity, a 10 MeV proton event has been in progress since 30/0245 UTC. IIB. Geophysical Activity Forecast: With the arrival of the most recent shock passage, geomagnetic field conditions are expected to be unsettled to active, with minor storm conditions possible during the first day of the forecast period. An enhancement of activity due to additional shock effects are also possible within the first two days, due to expected effects from the west limb CME of 29 December. Predominantly unsettled and quiet conditions are expected thereafter as shock passage effects wane. The 10 MeV proton event in progress is expected to end within the next 12-24 hours. III. Event Probabilities 31 Dec-02 Jan Class M 75/75/75 Class X 15/15/15 Proton 50/10/10 PCAF yellow IV. Penticton 10.7 cm Flux Observed 30 Dec 247 Predicted 31 Dec-02 Jan 250/250/245 90 Day Mean 30 Dec 225 V. Geomagnetic A Indices Observed Afr/Ap 29 Dec 013/010 Estimated Afr/Ap 30 Dec 018/018 Predicted Afr/Ap 31 Dec-02 Jan 020/020-015/015-012/010 VI. Geomagnetic Activity Probabilities 31 Dec-02 Jan A. Middle Latitudes Active 30/20/15 Minor storm 20/10/05 Major-severe storm 05/01/01 B. High Latitudes Active 35/25/15 Minor storm 25/15/05 Major-severe storm 05/01/01