:Product: 20010618RSGA.txt :Issued: 2001 Jun 18 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 169 Issued at 2200Z on 18 Jun 2001 IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity increased to moderate levels. Region 9506 (N17E34) produced an M2/2n parallel-ribbon flare at 28/2021 UTC associated with minor centimetric radio bursts. It also produced a long-duration C1/Sf flare at 18/0230 UTC. Region 9506 showed signs of penumbral decay in its leader spot and maintained a mixed polarity structure. Region 9503 (N14E07) produced isolated subflares including a C4/Sf at 18/1455 UTC. This region also possessed a mixed polarity structure and showed no significant changes during the period. Region 9502 (S26W08), which produced isolated major flares on 13 and 15 June, gradually decayed and possessed a simple bipolar structure. Today's noon 10.7 cm flux reading of 221 SFU was flare enhanced. The morning reading of 199 SFU was more reflective of prevailing conditions. IB. Solar Activity Forecast: Solar activity is expected to be at low to moderate levels. Regions 9503 and 9506 could produce isolated M-class flares. IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: Geomagnetic field activity ranged from quiet to minor storm levels with brief major storm periods detected at high latitudes. This disturbance was due to a CME passage at Earth that began around 18/0100 UTC. IIB. Geophysical Activity Forecast: Geomagnetic field activity is expected to be at quiet to active levels on the first day decreasing to quiet to unsettled levels for the rest of the period. III. Event Probabilities 19 Jun-21 Jun Class M 50/50/50 Class X 10/10/10 Proton 10/10/10 PCAF green IV. Penticton 10.7 cm Flux Observed 18 Jun 221 Predicted 19 Jun-21 Jun 200/195/195 90 Day Mean 18 Jun 173 V. Geomagnetic A Indices Observed Afr/Ap 17 Jun 005/009 Estimated Afr/Ap 18 Jun 027/029 Predicted Afr/Ap 19 Jun-21 Jun 012/015-008/012-007/010 VI. Geomagnetic Activity Probabilities 19 Jun-21 Jun A. Middle Latitudes Active 30/25/15 Minor storm 15/10/05 Major-severe storm 01/01/01 B. High Latitudes Active 35/30/20 Minor storm 20/15/10 Major-severe storm 05/01/01