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

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 301 Issued at 2200Z on 28 Oct 2021

IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity has been at high levels for the past 24 hours. The largest solar event of the period was a X1 event observed at 28/1535Z. There are currently 5 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is likely to be moderate with a chance for X-class flares on days one, two, and three (29 Oct, 30 Oct, 31 Oct).

IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 366 km/s at 27/2120Z. Total IMF reached 5 nT at 28/1629Z. The maximum southward component of Bz reached -2 nT at 28/1621Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 22 pfu at 28/1950Z. Protons greater than 100 MeV at geosynchronous orbit reached a peak level of 7 pfu at 28/1815Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 228 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (29 Oct), quiet to severe storm levels on day two (30 Oct) and quiet to minor storm levels on day three (31 Oct). Protons are expected to cross threshold on day one (29 Oct), have a chance of crossing threshold on day two (30 Oct) and have a slight chance of crossing threshold on day three (31 Oct).

III. Event probabilities 29 Oct-31 Oct
Class M 60/60/60
Class X 25/25/25
Proton 99/40/10
PCAF yellow

IV. Penticton 10.7 cm Flux
Observed 28 Oct 112
Predicted 29 Oct-31 Oct 113/114/114
90 Day Mean 28 Oct 084

V. Geomagnetic A Indices
Observed Afr/Ap 27 Oct 002/002
Estimated Afr/Ap 28 Oct 002/003
Predicted Afr/Ap 29 Oct-31 Oct 006/005-038/040-020/035

VI. Geomagnetic Activity Probabilities 29 Oct-31 Oct
A. Middle Latitudes
Active 15/30/30
Minor Storm 05/10/10
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 25/30/30
Major-severe storm 25/40/40