- Press Release
- Jun 7, 2023
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 117 Issued at 2200Z on 27 Apr 2023
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 27/1114Z from Region 3288 (S23W07). There are currently 7 numbered sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares on days one, two, and three (28 Apr, 29 Apr, 30 Apr).
IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at unsettled to active levels for the past 24 hours. Solar wind speed reached a peak of 720 km/s at 27/0546Z. Total IMF reached 8 nT at 26/2108Z. The maximum southward component of Bz reached -7 nT at 27/1124Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3355 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to minor storm levels on day one (28 Apr) and quiet to active levels on days two and three (29 Apr, 30 Apr).
III. Event probabilities 28 Apr-30 Apr
Class M 25/25/25
Class X 01/01/01
IV. Penticton 10.7 cm Flux
Observed 27 Apr 141
Predicted 28 Apr-30 Apr 135/135/135
90 Day Mean 27 Apr 158
V. Geomagnetic A Indices
Observed Afr/Ap 26 Apr 012/014
Estimated Afr/Ap 27 Apr 016/021
Predicted Afr/Ap 28 Apr-30 Apr 019/025-013/016-010/012
VI. Geomagnetic Activity Probabilities 28 Apr-30 Apr
A. Middle Latitudes
Minor Storm 20/10/10
Major-severe storm 05/01/01
B. High Latitudes
Minor Storm 20/20/20
Major-severe storm 30/20/30