- Press Release
- Jun 7, 2023
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 115 Issued at 2200Z on 25 Apr 2023
IA. Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C1 event observed at 25/0807Z from Region 3288 (S22E24). There are currently 5 numbered sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be very low with a chance for a C-class flares and a slight chance for an M-class flare on days one, two, and three (26 Apr, 27 Apr, 28 Apr).
IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 575 km/s at 25/0229Z. Total IMF reached 16 nT at 24/2106Z. The maximum southward component of Bz reached -4 nT at 25/1807Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 369 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (26 Apr), unsettled to active levels on day two (27 Apr) and quiet to minor storm levels on day three (28 Apr).
III. Event probabilities 26 Apr-28 Apr
Class M 10/10/10
Class X 01/01/01
IV. Penticton 10.7 cm Flux
Observed 25 Apr 131
Predicted 26 Apr-28 Apr 130/130/130
90 Day Mean 25 Apr 158
V. Geomagnetic A Indices
Observed Afr/Ap 24 Apr 039/072
Estimated Afr/Ap 25 Apr 007/009
Predicted Afr/Ap 26 Apr-28 Apr 007/008-015/018-019/025
VI. Geomagnetic Activity Probabilities 26 Apr-28 Apr
A. Middle Latitudes
Minor Storm 05/15/20
Major-severe storm 01/01/05
B. High Latitudes
Minor Storm 20/25/20
Major-severe storm 20/40/30