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

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 362 Issued at 2200Z on 28 Dec 2021

IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity has been at moderate levels for the past 24 hours. The largest solar event of the period was a M1 event observed at 28/0401Z from Region 2918 (N21W26). 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 (29 Dec, 30 Dec, 31 Dec).

IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 551 km/s at 28/1500Z. Total IMF reached 10 nT at 28/0125Z. The maximum southward component of Bz reached -8 nT at 28/0330Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 284 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (29 Dec) and quiet to unsettled levels on days two and three (30 Dec, 31 Dec).

III. Event probabilities 29 Dec-31 Dec
Class M 25/25/25
Class X 05/05/05
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 28 Dec 121
Predicted 29 Dec-31 Dec 122/122/120
90 Day Mean 28 Dec 093

V. Geomagnetic A Indices
Observed Afr/Ap 27 Dec 008/009
Estimated Afr/Ap 28 Dec 009/010
Predicted Afr/Ap 29 Dec-31 Dec 013/014-007/010-007/008

VI. Geomagnetic Activity Probabilities 29 Dec-31 Dec
A. Middle Latitudes
Active 30/25/20
Minor Storm 15/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/20
Minor Storm 30/30/30
Major-severe storm 45/30/25