:Product: 0604RSGA.txt :Issued: 2026 Jun 04 2200 UTC # Prepared jointly by the U.S. Dept. of Commerce, NOAA, # Space Weather Prediction Center and the U.S. Air Force. # Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 155 Issued at 2200Z on 04 Jun 2026 IA. Analysis of Solar Active Regions and Activity from 03/2100Z to 04/2100Z: Solar activity has been at low levels for the past 24 hours. There are currently 8 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares and a slight chance for an X-class flare on days one, two, and three (05 Jun, 06 Jun, 07 Jun). IIA. Geophysical Activity Summary 03/2100Z to 04/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 481 km/s at 03/2131Z. Total IMF reached 11 nT at 03/2257Z. The maximum southward component of Bz reached -9 nT at 04/0121Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 552 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at active to severe storm levels on day one (05 Jun), quiet to active levels on day two (06 Jun) and quiet to unsettled levels on day three (07 Jun). III. Event probabilities 05 Jun-07 Jun Class M 50/50/50 Class X 10/10/10 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 04 Jun 148 Predicted 05 Jun-07 Jun 145/143/140 90 Day Mean 04 Jun 125 V. Geomagnetic A Indices Observed Afr/Ap 03 Jun 011/010 Estimated Afr/Ap 04 Jun 023/041 Predicted Afr/Ap 05 Jun-07 Jun 042/055-018/020-010/012 VI. Geomagnetic Activity Probabilities 05 Jun-07 Jun A. Middle Latitudes Active 25/35/15 Minor Storm 20/15/05 Major-severe storm 40/05/01 B. High Latitudes Active 05/10/15 Minor Storm 20/30/25 Major-severe storm 75/60/20