Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 31 August 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 243 Issued at 2200Z on 31 Aug 2021

IA. Analysis of Solar Active Regions and Activity from 30/2100Z to 31/2100Z: 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 30/2134Z from Region 2860 (S29W36). There are currently 2 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be very low with a chance for a C-class or M-class flares on day one (01 Sep) and expected to be very low with a chance for a C-class flares and a slight chance for an M-class flare on days two and three (02 Sep, 03 Sep).

IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 414 km/s at 30/2254Z. Total IMF reached 5 nT at 31/1208Z. The maximum southward component of Bz reached -4 nT at 31/1122Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3240 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to minor storm levels on day one (01 Sep), unsettled to major storm levels on day two (02 Sep) and quiet to unsettled levels on day three (03 Sep).

III. Event probabilities 01 Sep-03 Sep
Class M 25/20/10
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 31 Aug 084
Predicted 01 Sep-03 Sep 082/082/082
90 Day Mean 31 Aug 079

V. Geomagnetic A Indices
Observed Afr/Ap 30 Aug 009/008
Estimated Afr/Ap 31 Aug 009/009
Predicted Afr/Ap 01 Sep-03 Sep 016/018-023/030-010/012

VI. Geomagnetic Activity Probabilities 01 Sep-03 Sep
A. Middle Latitudes
Active 40/35/30
Minor Storm 25/30/10
Major-severe storm 05/10/01
B. High Latitudes
Active 10/10/15
Minor Storm 25/25/30
Major-severe storm 65/65/40