Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 110 Issued at 2200Z on 20 Apr 2023
IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C3 event observed at 20/0922Z from Region 3281 (S22W22). There are currently 6 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 (21 Apr, 22 Apr, 23 Apr).
IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 1083 km/s at 20/0545Z. Total IMF reached 27 nT at 20/0610Z. The maximum southward component of Bz reached -18 nT at 20/0610Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 113 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to minor storm levels on day one (21 Apr), quiet to active levels on day two (22 Apr) and quiet to unsettled levels on day three (23 Apr).
III. Event probabilities 21 Apr-23 Apr
Class M 35/30/30
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 20 Apr 147
Predicted 21 Apr-23 Apr 145/140/135
90 Day Mean 20 Apr 161
V. Geomagnetic A Indices
Observed Afr/Ap 19 Apr 009/012
Estimated Afr/Ap 20 Apr 009/012
Predicted Afr/Ap 21 Apr-23 Apr 017/020-014/016-010/012
VI. Geomagnetic Activity Probabilities 21 Apr-23 Apr
A. Middle Latitudes
Active 40/30/30
Minor Storm 25/10/10
Major-severe storm 05/01/01
B. High Latitudes
Active 10/15/15
Minor Storm 25/25/30
Major-severe storm 60/40/40
Space weather
