:Product: 20010416RSGA.txt :Issued: 2001 Apr 16 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 106 Issued at 2200Z on 16 Apr 2001 IA. Analysis of Solar Active Regions and Activity from 15/2100Z to 16/2100Z: Solar activity was moderate. An optically uncorrelated M1 event occurred at 16/0622 UTC. New Region 9430 (S16W33) was numbered today. IB. Solar Activity Forecast: Solar activity is expected to be low to moderate. IIA. Geophysical Activity Summary 15/2100Z to 16/2100Z: The geomagnetic field was quiet to unsettled. The greater than 10 MeV and greater than 100 MeV proton events that started yesterday are still in progress. Peak flux for the greater than 10 MeV protons was 951 pfu at 15/1920 UTC and the peak flux for the greater than 100 MeV was 146 pfu at 15/1525 UTC. The greater than 2 MeV electrons at geosynchronous orbit were at high levels and remained above threshold through the period. The polar cap absorption (PCA) event that started yesterday is still in progress. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be unsettled to active for April 17. Active to minor storm conditions are expected for April 18 as a result of the X14/2b flare on April 15, and possible effects from a well positioned coronal hole. Unsettled to active conditions are expected to return on April 19. The greater than 10 MeV proton event is expected to continue for most of the period, and the greater than 100 MeV proton event is expected to go below threshold sometime on April 17. III. Event Probabilities 17 Apr-19 Apr Class M 70/60/50 Class X 25/10/10 Proton 99/50/10 PCAF in progress IV. Penticton 10.7 cm Flux Observed 16 Apr 123 Predicted 17 Apr-19 Apr 130/140/150 90 Day Mean 16 Apr 165 V. Geomagnetic A Indices Observed Afr/Ap 15 Apr 009/013 Estimated Afr/Ap 16 Apr 010/012 Predicted Afr/Ap 17 Apr-19 Apr 015/020-020/035-015/030 VI. Geomagnetic Activity Probabilities 17 Apr-19 Apr A. Middle Latitudes Active 25/50/25 Minor storm 05/10/05 Major-severe storm 01/05/01 B. High Latitudes Active 35/60/50 Minor storm 10/15/15 Major-severe storm 05/10/10