Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 232 Issued at 2200Z on 20 Aug 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 20/0626Z from Region 3409 (N22W70). There are currently 7 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with a slight chance for an M-class flare on days one, two, and three (21 Aug, 22 Aug, 23 Aug).

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 690 km/s at 20/1200Z. Total IMF reached 9 nT at 20/0528Z. The maximum southward component of Bz reached -6 nT at 20/2013Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 109 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one, two, and three (21 Aug, 22 Aug, 23 Aug).

III. Event probabilities 21 Aug-23 Aug
Class M 15/15/15
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 20 Aug 146
Predicted 21 Aug-23 Aug 153/153/155
90 Day Mean 20 Aug 166

V. Geomagnetic A Indices
Observed Afr/Ap 19 Aug 008/010
Estimated Afr/Ap 20 Aug 010/010
Predicted Afr/Ap 21 Aug-23 Aug 008/010-008/010-008/010

VI. Geomagnetic Activity Probabilities 21 Aug-23 Aug
A. Middle Latitudes
Active 15/15/15
Minor Storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 20/20/20
Major-severe storm 20/20/20

Space Weather