Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 28 August 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 240 Issued at 2200Z on 28 Aug 2021

IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity has been at moderate levels for the past 24 hours. The largest solar event of the period was a M4 event observed at 28/0611Z from Region 2860 (S29W10). There are currently 4 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, two, and three (29 Aug, 30 Aug, 31 Aug).

IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field has been at quiet to minor storm levels for the past 24 hours.Solar wind speed reached a peak of 389 km/s at 28/1718Z. Total IMF reached 14 nT at 27/2100Z. The maximum southward component of Bz reached -12 nT at 27/2131Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 10655 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to minor storm levels on days one and two (29 Aug, 30 Aug) and quiet levels on day three (31 Aug).

III. Event probabilities 29 Aug-31 Aug
Class M 30/30/30
Class X 05/05/05
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 28 Aug 090
Predicted 29 Aug-31 Aug 090/090/090
90 Day Mean 28 Aug 079

V. Geomagnetic A Indices
Observed Afr/Ap 27 Aug 019/021
Estimated Afr/Ap 28 Aug 013/016
Predicted Afr/Ap 29 Aug-31 Aug 011/018-022/025-007/008

VI. Geomagnetic Activity Probabilities 29 Aug-31 Aug
A. Middle Latitudes
Active 35/30/20
Minor Storm 35/40/05
Major-severe storm 20/25/01
B. High Latitudes
Active 05/05/15
Minor Storm 20/15/30
Major-severe storm 75/80/30