:Product: 20030711RSGA.txt :Issued: 2003 Jul 11 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 192 Issued at 2200Z on 11 Jul 2003 IA. Analysis of Solar Active Regions and Activity from 10/2100Z to 11/2100Z: Solar activity decreased to low levels today. Several minor B and C-class flares were observed during the period. Even though Region 397 (N12, L=028) has rotated beyond the west limb it managed to produce most of the recorded C-class activity. Region 401 (S09W05) produced the largest flare of the period, a C2.9 that occurred at 11/0739Z. This region has doubled in penumbral coverage during the interval although it remains simply structured. Region 400 (N06W65) was quiescent while undergoing steady decay. The magnetic gamma structure remains vaguely intact. Regions 405 (S10E66), 406 (S19W11), and 407 (N09E31) were newly assigned today. IB. Solar Activity Forecast: Solar activity is expected to be at low levels. With continued growth, Region 401 may become capable of producing isolated M-class flares. IIA. Geophysical Activity Summary 10/2100Z to 11/2100Z: The geomagnetic field was at quiet to major storm levels. An extended period of southward Bz (-10 nT) led to the elevated conditions. An isolated period of major storm levels was observed between 11/0600 and 11/0900Z. An increase in the solar wind speed began near mid-period and is likely to be the onset of a recurrent coronal hole. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at predominantly unsettled to active levels. Isolated minor storm conditions may occur at both middle and high latitudes, especially during nighttime hours due to high speed coronal hole stream effects throughout the period. Day three may see further elevated conditions due to an anticipated transient passage from the M3.6 x-ray flare that occurred on 10 July. III. Event Probabilities 12 Jul-14 Jul Class M 40/40/30 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 11 Jul 122 Predicted 12 Jul-14 Jul 115/110/120 90 Day Mean 11 Jul 125 V. Geomagnetic A Indices Observed Afr/Ap 10 Jul 006/008 Estimated Afr/Ap 11 Jul 023/035 Predicted Afr/Ap 12 Jul-14 Jul 015/020-015/020-030/045 VI. Geomagnetic Activity Probabilities 12 Jul-14 Jul A. Middle Latitudes Active 35/35/50 Minor storm 20/20/30 Major-severe storm 10/10/15 B. High Latitudes Active 45/45/30 Minor storm 30/30/40 Major-severe storm 15/15/25