Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 16 December 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 350 Issued at 2200Z on 16 Dec 2021

IA. Analysis of Solar Active Regions and Activity from 15/2100Z to 16/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C3 event observed at 16/1527Z from Region 2909 (S21E58). There are currently 7 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 day one (17 Dec) and likely to be low with a slight chance for an M-class flare on days two and three (18 Dec, 19 Dec).

IIA. Geophysical Activity Summary 15/2100Z to 16/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 558 km/s at 16/1123Z. Total IMF reached 7 nT at 16/0932Z. The maximum southward component of Bz reached -5 nT at 16/0942Z. 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 day one (17 Dec) and quiet levels on days two and three (18 Dec, 19 Dec).

III. Event probabilities 17 Dec-19 Dec
Class M 25/20/15
Class X 05/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 16 Dec 118
Predicted 17 Dec-19 Dec 118/118/118
90 Day Mean 16 Dec 087

V. Geomagnetic A Indices
Observed Afr/Ap 15 Dec 008/006
Estimated Afr/Ap 16 Dec 009/008
Predicted Afr/Ap 17 Dec-19 Dec 008/008-006/005-006/005

VI. Geomagnetic Activity Probabilities 17 Dec-19 Dec
A. Middle Latitudes
Active 15/10/10
Minor Storm 05/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 25/20/20
Major-severe storm 25/20/15