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

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 365 Issued at 2200Z on 31 Dec 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 C9 event observed at 31/0656Z from Region 2918 (N22W67). There are currently 4 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is likely to be low with a slight chance for an M-class flare on day one (01 Jan) and expected to be very low with a chance for a C-class flares and a slight chance for an M-class flare on days two and three (02 Jan, 03 Jan).

IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 472 km/s at 30/2226Z. Total IMF reached 7 nT at 31/2021Z. The maximum southward component of Bz reached -4 nT at 31/1419Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 340 pfu.

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

III. Event probabilities 01 Jan-03 Jan
Class M 20/10/10
Class X 05/05/05
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 31 Dec 102
Predicted 01 Jan-03 Jan 102/102/098
90 Day Mean 31 Dec 093

V. Geomagnetic A Indices
Observed Afr/Ap 30 Dec 007/006
Estimated Afr/Ap 31 Dec 004/005
Predicted Afr/Ap 01 Jan-03 Jan 007/008-011/012-007/008

VI. Geomagnetic Activity Probabilities 01 Jan-03 Jan
A. Middle Latitudes
Active 25/35/25
Minor Storm 10/15/10
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/30/30
Major-severe storm 40/50/40