:Product: 20040119RSGA.txt :Issued: 2004 Jan 19 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 019 Issued at 2200Z on 19 Jan 2004 IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity was moderate. Region 540 (S14W10) produced two M1 flares this period, at 19/0532Z and again at 19/1240Z. It was also the source of several C-class events including a C8/Sf at 19/2002Z. Some penumbral decay was noted in the trailing spots in this group; however, considerable complexity still exists and a weak delta configuration was identified. Region 542 (N08E15) was spotless early on 18 January, but two new sunspot clusters emerged quite rapidly late on the 18th and continued to develop through this period. These spot groups may be two separate regions. Another new spot group emerged rapidly near the trailing spots in Region 540. This new beta-gamma group was numbered as Region 543 (S18E05) and produced a C3 flare at 19/1439Z. Portions of the very large circular filament in the northwest quadrant became quite active this period. IB. Solar Activity Forecast: Solar activity is expected to be at moderate levels. Further M-class activity is likely from Region 540. The new emerging flux and white light developments in Region 542 and newly numbered 543 suggest at least C-class potential. IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic field was quiet to active. Solar wind speed remains elevated (560 to 660 km/s) since the onset of a high speed coronal hole stream on 16 January. IMF Bz was predominantly northward although there were some periods of sustained southward Bz. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels again today IIB. Geophysical Activity Forecast: The geomagnetic field is expected to continue at predominantly quiet to active levels. Isolated minor storm periods are possible on 20 - 21 January. The coronal hole high speed stream that is currently in progress is expected to subside by 21 January. A CME associated with the M5 flare on 17 January may have a weak impact on the geomagnetic field on 20 January, slightly enhancing the current disturbance. Mostly quiet to unsettled conditions are expected on 22 January. III. Event Probabilities 20 Jan-22 Jan Class M 30/30/30 Class X 05/05/05 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 19 Jan 135 Predicted 20 Jan-22 Jan 135/135/135 90 Day Mean 19 Jan 138 V. Geomagnetic A Indices Observed Afr/Ap 18 Jan 015/018 Estimated Afr/Ap 19 Jan 015/020 Predicted Afr/Ap 20 Jan-22 Jan 015/020-012/018-010/012 VI. Geomagnetic Activity Probabilities 20 Jan-22 Jan A. Middle Latitudes Active 30/25/20 Minor storm 10/05/01 Major-severe storm 05/01/01 B. High Latitudes Active 40/30/25 Minor storm 20/10/05 Major-severe storm 10/05/01