:Product: 0526RSGA.txt :Issued: 2025 May 26 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 146 Issued at 2200Z on 26 May 2025 IA. Analysis of Solar Active Regions and Activity from 25/2100Z to 26/2100Z: Solar activity has been at moderate levels for the past 24 hours. There are currently 8 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is likely to be moderate with a chance for X-class flares on days one, two, and three (27 May, 28 May, 29 May). IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 495 km/s at 26/0639Z. Total IMF reached 10 nT at 26/0520Z. The maximum southward component of Bz reached -9 nT at 26/0531Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1021 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (27 May), quiet to minor storm levels on day two (28 May) and quiet to active levels on day three (29 May). Protons have a slight chance of crossing threshold on days one, two, and three (27 May, 28 May, 29 May). III. Event probabilities 27 May-29 May Class M 70/70/70 Class X 30/30/30 Proton 15/15/15 PCAF green IV. Penticton 10.7 cm Flux Observed 26 May 133 Predicted 27 May-29 May 135/130/125 90 Day Mean 26 May 155 V. Geomagnetic A Indices Observed Afr/Ap 25 May 008/ 006 Estimated Afr/Ap 26 May 008/008 Predicted Afr/Ap 27 May-29 May 008/008-016/025-015/016 VI. Geomagnetic Activity Probabilities 27 May-29 May A. Middle Latitudes Active 20/40/35 Minor Storm 05/25/15 Major-severe storm 01/05/01 B. High Latitudes Active 15/10/10 Minor Storm 25/25/30 Major-severe storm 25/60/50