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

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 304 Issued at 2200Z on 31 Oct 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 C2 event observed at 31/0706Z from Region 2891 (N16E15). There are currently 5 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 (01 Nov, 02 Nov, 03 Nov).

IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z: The geomagnetic field has been at unsettled to minor storm levels for the past 24 hours. Solar wind speed reached a peak of 465 km/s at 31/1905Z. Total IMF reached 13 nT at 31/1103Z. The maximum southward component of Bz reached -11 nT at 31/1136Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 11 pfu at 30/2105Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 133 pfu.

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

III. Event probabilities 01 Nov-03 Nov
Class M 35/35/35
Class X 05/05/05
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 31 Oct 103
Predicted 01 Nov-03 Nov 103/102/100
90 Day Mean 31 Oct 085

V. Geomagnetic A Indices
Observed Afr/Ap 30 Oct 008/013
Estimated Afr/Ap 31 Oct 024/042
Predicted Afr/Ap 01 Nov-03 Nov 013/020-007/008-006/005

VI. Geomagnetic Activity Probabilities 01 Nov-03 Nov
A. Middle Latitudes
Active 30/20/10
Minor Storm 25/05/01
Major-severe storm 10/01/01
B. High Latitudes
Active 10/15/20
Minor Storm 20/25/20
Major-severe storm 60/25/10