Joint USAF/NOAA Report of Solar and Geophysical Activity 16 Aug 2002
Joint USAF/NOAA Report of Solar and Geophysical Activity SDF Number 228 Issued at 2200Z on 16 Aug 2002 IA. Analysis of Solar Active Regions and Activity from 15/2100Z to 16/2100Z: Solar activity increased to high levels. Region 69 (S07E11) continues to grow at a gradual pace in both penumbral coverage and magnetic complexity. This region produced the largest flare during the period, a long duration M5/2n occurring at 16/1232 UTC with an associated 1600 sfu Tenflare and a Type II radio sweep with an estimated shock velocity of 1836 km/s. Moderate to strong discrete radio bursts and a strong Type IV radio sweep were also associated with this flare. SOHO/LASCO reported a full-halo CME surrounding the C2 occulting disk by 16/1254 UTC. Region 61 (now beyond the west limb) produced an M2/Sf flare at 16/0611 UTC just prior to exiting the disk. A Type II radio sweep with an estimated shock velocity of 1450 km/s was associated with this flare. Region 78 (S13W39) produced an M1/Sf at 16/2333 UTC. Newly numbered region 81 (N17E61) was assigned today. IB. Solar Activity Forecast: Solar activity is expected to be at moderate levels. Region 69 has the potential to produce further major flare activity. IIA. Geophysical Activity Summary 15/2100Z to 16/2100Z: The geomagnetic field was at unsettled to minor storm levels. A slight indication of a weak shock passage at the ACE spacecraft was observed at the beginning of the period. The greater than 2 MeV electron flux at geo-synchronous orbit exceeded threshold at 16/1505 UTC, preliminary maximum flux was 1340 pfu at 16/1530 UTC. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to active levels through most of day one of the period. Minor to major storm conditions may begin as early as day two of the period in response to the major flare and associated CME mentioned in IA. Day three should see a return to unsettled to active conditions as the potential effects from expected shock subside. The greater than 2 MeV electron flux should see a return to moderate levels by day one of the period. III. Event Probabilities 17 Aug-19 Aug Class M 75/75/75 Class X 15/15/15 Proton 10/10/10 PCAF yellow IV. Penticton 10.7 cm Flux Observed 16 Aug 214 Predicted 17 Aug-19 Aug 215/220/225 90 Day Mean 16 Aug 166 V. Geomagnetic A Indices Observed Afr/Ap 15 Aug 018/019 Estimated Afr/Ap 16 Aug 020/020 Predicted Afr/Ap 17 Aug-19 Aug 020/020-050/070-018/020 VI. Geomagnetic Activity Probabilities 17 Aug-19 Aug A. Middle Latitudes Active 40/30/40 Minor storm 15/25/15 Major-severe storm 10/25/10 B. High Latitudes Active 35/30/30 Minor storm 15/30/15 Major-severe storm 15/30/15
