:Product: 20040527RSGA.txt :Issued: 2004 May 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 148 Issued at 2200Z on 27 May 2004 IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity was at low levels today. Region 618 (S10W27) produced a C1/Sf flare that occurred at 27/0027Z. This region continued to show decay in magnetic complexity and sunspot area during the period. The delta structure near region center remains intact. Region 619 (S09W89) managed to produce a C1 flare just before the sunspots vanished in white light. No new regions were numbered today. IB. Solar Activity Forecast: Solar activity is expected to be at low levels. Region 618 continues to exhibit the potential for producing isolated M-class flares. IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field was at quiet to unsettled levels. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels. NOTE: The ACE spacecraft orbit will bring ACE nearly in line with the Sun from about May 30 to June 2, 2004. During that time solar radio noise is expected to interfere with spacecraft telemetry resulting in the loss of solar wind plasma, magnetic field, and particle data. III. Event Probabilities 28 May-30 May Class M 40/40/40 Class X 05/05/05 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 27 May 102 Predicted 28 May-30 May 100/100/105 90 Day Mean 27 May 105 V. Geomagnetic A Indices Observed Afr/Ap 26 May 003/006 Estimated Afr/Ap 27 May 004/008 Predicted Afr/Ap 28 May-30 May 004/010-004/010-008/012 VI. Geomagnetic Activity Probabilities 28 May-30 May A. Middle Latitudes Active 10/10/15 Minor storm 05/05/05 Major-severe storm 05/01/05 B. High Latitudes Active 20/20/25 Minor storm 10/10/15 Major-severe storm 05/05/05