:Product: Report of Solar-Geophysical Activity :Issued: 2024 Mar 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 87 Issued at 2200Z on 27 Mar 2024 IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity has been at moderate levels for the past 24 hours. The largest solar event of the period was a M1 event observed at 26/2158Z. There are currently 6 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is expected to be moderate with a chance for X-class flares on days one and two (28 Mar, 29 Mar) and expected to be low with a chance for M-class flares and a slight chance for an X-class flare on day three (30 Mar). IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 528 km/s at 27/0957Z. Total IMF reached 7 nT at 27/0814Z. The maximum southward component of Bz reached -3 nT at 27/0623Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 2 pfu at 27/0015Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 242 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on day one (28 Mar) and quiet to unsettled levels on days two and three (29 Mar, 30 Mar). Protons have a chance of crossing threshold on days one and two (28 Mar, 29 Mar) and have a slight chance of crossing threshold on day three (30 Mar). III. Event probabilities 28 Mar-30 Mar Class M 75/75/40 Class X 25/25/10 Proton 30/30/10 PCAF green IV. Penticton 10.7 cm Flux Observed 27 Mar 175 Predicted 28 Mar-30 Mar 180/175/170 90 Day Mean 27 Mar 164 V. Geomagnetic A Indices Observed Afr/Ap 26 Mar 011/009 Estimated Afr/Ap 27 Mar 008/008 Predicted Afr/Ap 28 Mar-30 Mar 005/005-007/010-007/008 VI. Geomagnetic Activity Probabilities 28 Mar-30 Mar A. Middle Latitudes Active 10/20/15 Minor Storm 01/05/05 Major-severe storm 01/01/01 B. High Latitudes Active 15/15/15 Minor Storm 20/30/25 Major-severe storm 20/30/25