Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 221 Issued at 2200Z on 09 Aug 2023

IA. Analysis of Solar Active Regions and Activity from 08/2100Z to 09/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C5 event observed at 09/0701Z from Region 3387 (N18W0*). There are currently 7 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 and two (10 Aug, 11 Aug) and likely to be low with a slight chance for an M-class flare on day three (12 Aug).

IIA. Geophysical Activity Summary 08/2100Z to 09/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 483 km/s at 09/0024Z. Total IMF reached 7 nT at 09/0803Z. The maximum southward component of Bz reached -4 nT at 09/1244Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 47 pfu at 09/0025Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1772 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (10 Aug) and quiet levels on days two and three (11 Aug, 12 Aug). Protons greater than 10 Mev have a slight chance of crossing threshold on day one (10 Aug).

III. Event probabilities 10 Aug-12 Aug
Class M 40/25/15
Class X 05/05/01
Proton 15/05/01
PCAF yellow

IV. Penticton 10.7 cm Flux
Observed 09 Aug 153
Predicted 10 Aug-12 Aug 150/150/150
90 Day Mean 09 Aug 166

V. Geomagnetic A Indices
Observed Afr/Ap 08 Aug 007/010
Estimated Afr/Ap 09 Aug 006/007
Predicted Afr/Ap 10 Aug-12 Aug 008/012-006/005-006/005

VI. Geomagnetic Activity Probabilities 10 Aug-12 Aug
A. Middle Latitudes
Active 25/10/10
Minor Storm 10/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 25/15/15
Major-severe storm 35/10/10

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