:Product: 0527RSGA.txt :Issued: 2025 May 27 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 147 Issued at 2200Z on 27 May 2025 IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: 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 likely to be moderate with a slight chance for an X-class flare on days one, two, and three (28 May, 29 May, 30 May). IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 517 km/s at 27/2015Z. Total IMF reached 13 nT at 27/1919Z. The maximum southward component of Bz reached -8 nT at 27/2043Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 461 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to minor storm levels on day one (28 May) and quiet to active levels on days two and three (29 May, 30 May). Protons have a slight chance of crossing threshold on days one, two, and three (28 May, 29 May, 30 May). III. Event probabilities 28 May-30 May Class M 55/55/55 Class X 15/15/15 Proton 10/10/10 PCAF green IV. Penticton 10.7 cm Flux Observed 27 May 137 Predicted 28 May-30 May 133/130/130 90 Day Mean 27 May 154 V. Geomagnetic A Indices Observed Afr/Ap 26 May 008/ 008 Estimated Afr/Ap 27 May 013/015 Predicted Afr/Ap 28 May-30 May 018/025-015/016-009/012 VI. Geomagnetic Activity Probabilities 28 May-30 May A. Middle Latitudes Active 40/35/30 Minor Storm 30/15/10 Major-severe storm 05/01/01 B. High Latitudes Active 10/10/15 Minor Storm 25/30/30 Major-severe storm 65/50/40