:Product: 20030521RSGA.txt :Issued: 2003 May 21 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 141 Issued at 2200Z on 21 May 2003 IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity was at low levels. Region 362 (S12W03) produced a C1 flare at 0604Z and continues to exhibit a beta gamma magnetic configuration. A nine-degree solar filament disappeared near N19W05 at 20/0005Z. No Earth directed CME was observed in LASCO imagery. IB. Solar Activity Forecast: Solar activity is expected to be at low levels. Regions 362 and 364 have the potential for C-class flares. IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field was at quiet to active levels. Periods of southward Bz near -10 nT resulted in two active periods during the day. Solar wind speed began a steady increase, most likely due to the onset of an equatorial coronal hole high speed flow. Wind speed increased from 400 km/s to over 600 km/s and continues to rise. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels. The coronal hole high speed flow is expected to produce active conditions during the period with a chance of isolated minor storming particularly at the higher latitudes. III. Event Probabilities 22 May-24 May Class M 10/15/15 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 21 May 119 Predicted 22 May-24 May 125/135/140 90 Day Mean 21 May 124 V. Geomagnetic A Indices Observed Afr/Ap 20 May 009/012 Estimated Afr/Ap 21 May 015/015 Predicted Afr/Ap 22 May-24 May 015/020-015/020-015/020 VI. Geomagnetic Activity Probabilities 22 May-24 May A. Middle Latitudes Active 30/35/40 Minor storm 10/15/20 Major-severe storm 01/05/05 B. High Latitudes Active 40/50/50 Minor storm 20/25/25 Major-severe storm 10/15/15