Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 20 August 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 232 Issued at 2200Z on 20 Aug 2021

IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: 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 20/1557Z. There are currently 1 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 flares on days one, two, and three (21 Aug, 22 Aug, 23 Aug).

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 353 km/s at 20/0320Z. Total IMF reached 8 nT at 20/1255Z. The maximum southward component of Bz reached -7 nT at 20/1234Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 145 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one, two, and three (21 Aug, 22 Aug, 23 Aug).

III. Event probabilities 21 Aug-23 Aug
Class M 05/05/05
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 20 Aug 078
Predicted 21 Aug-23 Aug 079/079/079
90 Day Mean 20 Aug 079

V. Geomagnetic A Indices
Observed Afr/Ap 19 Aug 005/005
Estimated Afr/Ap 20 Aug 005/005
Predicted Afr/Ap 21 Aug-23 Aug 008/008-008/008-008/010

VI. Geomagnetic Activity Probabilities 21 Aug-23 Aug
A. Middle Latitudes
Active 20/20/20
Minor Storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/30/30
Major-severe storm 25/25/25