:Product: 20030727RSGA.txt :Issued: 2003 Jul 27 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 208 Issued at 2200Z on 27 Jul 2003 IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity was at very low levels. Active regions were quiescent through the period. Newly numbered Region 421 (S08E77) remains too close to the east limb for a detailed analysis of its complexity. IB. Solar Activity Forecast: Solar activity is expected to be at predominantly very low levels. Based on SXI imagery Region 421 may have the potential to produce C-class flares, pending further analysis, as it has yet to fully rotate onto the visible disk. IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field was at unsettled to minor storm levels. A recurrent high speed coronal hole stream and a sustained southward Bz are believed responsible for the elevated activity. The solar wind speed exceeded 800 km/s at approximately 27/0600Z. NASA/ACE data also indicates a possible transient passage very early in the period. The greater than 2 MeV electron fluxes at geosynchronous orbit reached moderate levels today. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at predominantly unsettled to active levels. Isolated minor storm conditions are possible at both mid and high latitudes due to the effects of the high speed solar wind for days one and two. Day three should see a decrease in the elevated solar wind speeds and the associated effects. III. Event Probabilities 28 Jul-30 Jul Class M 01/01/01 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 27 Jul 102 Predicted 28 Jul-30 Jul 110/115/115 90 Day Mean 27 Jul 126 V. Geomagnetic A Indices Observed Afr/Ap 26 Jul 020/026 Estimated Afr/Ap 27 Jul 020/030 Predicted Afr/Ap 28 Jul-30 Jul 020/030-020/030-012/025 VI. Geomagnetic Activity Probabilities 28 Jul-30 Jul A. Middle Latitudes Active 40/40/25 Minor storm 25/25/10 Major-severe storm 10/10/05 B. High Latitudes Active 40/40/35 Minor storm 35/35/30 Major-severe storm 20/20/15