- Press Release
- Jun 7, 2023
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 106 Issued at 2200Z on 16 Apr 2023
IA. Analysis of Solar Active Regions and Activity from 15/2100Z to 16/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C9 event observed at 16/1744Z. There are currently 9 numbered sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares and a slight chance for an X-class flare on days one, two, and three (17 Apr, 18 Apr, 19 Apr).
IIA. Geophysical Activity Summary 15/2100Z to 16/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 1196 km/s at 16/0034Z. Total IMF reached 8 nT at 16/0109Z. The maximum southward component of Bz reached -5 nT at 16/1821Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 165 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on days one, two, and three (17 Apr, 18 Apr, 19 Apr).
III. Event probabilities 17 Apr-19 Apr
Class M 50/50/50
Class X 10/10/10
IV. Penticton 10.7 cm Flux
Observed 16 Apr 178
Predicted 17 Apr-19 Apr 178/170/168
90 Day Mean 16 Apr 164
V. Geomagnetic A Indices
Observed Afr/Ap 15 Apr 008/007
Estimated Afr/Ap 16 Apr 007/008
Predicted Afr/Ap 17 Apr-19 Apr 005/005-006/005-005/005
VI. Geomagnetic Activity Probabilities 17 Apr-19 Apr
A. Middle Latitudes
Minor Storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Minor Storm 20/20/20
Major-severe storm 15/15/15