Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 238 Issued at 2200Z on 26 Aug 2023

IA. Analysis of Solar Active Regions and Activity from 25/2100Z to 26/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C2 event observed at 26/1006Z from Region 3413 (N12E01). There are currently 6 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 (27 Aug, 28 Aug, 29 Aug).

IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 493 km/s at 25/2226Z. Total IMF reached 7 nT at 26/0312Z. The maximum southward component of Bz reached -7 nT at 26/0211Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 285 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (27 Aug) and quiet to unsettled levels on days two and three (28 Aug, 29 Aug).

III. Event probabilities 27 Aug-29 Aug
Class M 20/20/20
Class X 05/05/05
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 26 Aug 139
Predicted 27 Aug-29 Aug 135/140/140
90 Day Mean 26 Aug 165

V. Geomagnetic A Indices
Observed Afr/Ap 25 Aug 007/004
Estimated Afr/Ap 26 Aug 008/008
Predicted Afr/Ap 27 Aug-29 Aug 009/010-010/010-008/008

VI. Geomagnetic Activity Probabilities 27 Aug-29 Aug
A. Middle Latitudes
Active 25/20/15
Minor Storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 15/20/20
Major-severe storm 10/20/20

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