:Product: 20010929RSGA.txt :Issued: 2001 Sep 29 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 272 Issued at 2200Z on 29 Sep 2001 IA. Analysis of Solar Active Regions and Activity from 28/2100Z to 29/2100Z: Solar activity has been moderate. Two M1/1f flares were observed -- the first at 28/2125 UTC from Region 9634 (N12W15), and the second a long duration event at 29/1106 UTC from Region 9636 (N13W02). For the latter event, SOHO/LASCO imagery suggests an associated faint halo with an earthward-directed component possible. Region 9628 (S17W62), the largest on the visible disk, also produced several optical flares with strong C-level enhancements throughout the first half of the period. New Region 9642 (N03E70) was numbered today. IB. Solar Activity Forecast: Solar activity is expected to be predominantly moderate over the next three days. Isolated major flares are possible, particularly from Region 9628 and nearby Region 9632 (S18W48). IIA. Geophysical Activity Summary 28/2100Z to 29/2100Z: Geomagnetic field activity has been quiet to active. A 17 nT sudden impulse was observed on the Boulder magnetometer at 29/0940 UTC, preceded by an earlier shock passage observed on the ACE satellite. Several active periods occurred through the remainder of the day. Solar wind speed remains elevated and IMF signatures suggest the predominant influence of a coronal hole high speed stream. The proton event which began on 25 September remains in progress but continues to wane, with current 10MeV flux levels at about 25 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be predominantly active for the next two days, under the combined influence of high speed stream effects and possible transient shock passages from the CME activity of 28 September. Isolated minor storm conditions may occur at higher latitudes during this period. Today's CME activity may further result in additional shock passage effects on day three. The proton event in progress is expected to end within the next 24 to 36 hours, barring further enhancement from any major flares. III. Event Probabilities 30 Sep-02 Oct Class M 80/80/80 Class X 25/25/25 Proton 99/50/20 PCAF yellow IV. Penticton 10.7 cm Flux Observed 29 Sep 240 Predicted 30 Sep-02 Oct 240/240/235 90 Day Mean 29 Sep 175 V. Geomagnetic A Indices Observed Afr/Ap 28 Sep 010/013 Estimated Afr/Ap 29 Sep 015/020 Predicted Afr/Ap 30 Sep-02 Oct 020/030-020/020-018/018 VI. Geomagnetic Activity Probabilities 30 Sep-02 Oct A. Middle Latitudes Active 30/30/25 Minor storm 15/15/10 Major-severe storm 10/10/10 B. High Latitudes Active 35/35/30 Minor storm 20/20/15 Major-severe storm 15/10/10