Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 235 Issued at 2200Z on 23 Aug 2023

IA. Analysis of Solar Active Regions and Activity from 22/2100Z to 23/2100Z: 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 22/2304Z from Region 3405 (N09W33). There are currently 8 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 (24 Aug, 25 Aug, 26 Aug).

IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 495 km/s at 22/2125Z. Total IMF reached 6 nT at 23/2031Z. The maximum southward component of Bz reached -2 nT at 22/2253Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 362 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one and two (24 Aug, 25 Aug) and quiet levels on day three (26 Aug).

III. Event probabilities 24 Aug-26 Aug
Class M 15/10/10
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 23 Aug 147
Predicted 24 Aug-26 Aug 150/155/155
90 Day Mean 23 Aug 166

V. Geomagnetic A Indices
Observed Afr/Ap 22 Aug 012/008
Estimated Afr/Ap 23 Aug 004/005
Predicted Afr/Ap 24 Aug-26 Aug 007/008-007/008-005/005

VI. Geomagnetic Activity Probabilities 24 Aug-26 Aug
A. Middle Latitudes
Active 15/15/10
Minor Storm 05/05/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 20/20/15
Major-severe storm 20/20/10

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