Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 21 August 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 233 Issued at 2200Z on 21 Aug 2021

IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C1 event observed at 20/2200Z from new Region 2859. 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 flares on days one, two, and three (22 Aug, 23 Aug, 24 Aug).

IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 356 km/s at 21/0832Z. Total IMF reached 7 nT at 21/0439Z. The maximum southward component of Bz reached -3 nT at 21/1314Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 154 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one and two (22 Aug, 23 Aug) and quiet to active levels on day three (24 Aug).

III. Event probabilities 22 Aug-24 Aug
Class M 05/05/05
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 21 Aug 077
Predicted 22 Aug-24 Aug 077/077/077
90 Day Mean 21 Aug 079

V. Geomagnetic A Indices
Observed Afr/Ap 20 Aug 006/007
Estimated Afr/Ap 21 Aug 004/005
Predicted Afr/Ap 22 Aug-24 Aug 008/008-008/010-011/014

VI. Geomagnetic Activity Probabilities 22 Aug-24 Aug
A. Middle Latitudes
Active 20/20/40
Minor Storm 05/05/15
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/10
Minor Storm 30/30/30
Major-severe storm 25/25/55