Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 15 December 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 349 Issued at 2200Z on 15 Dec 2021

IA. Analysis of Solar Active Regions and Activity from 14/2100Z to 15/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C8 event observed at 15/1044Z from Region 2907 (S21E39). 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 day one (16 Dec) and likely to be low with a slight chance for an M-class flare on days two and three (17 Dec, 18 Dec).

IIA. Geophysical Activity Summary 14/2100Z to 15/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 568 km/s at 15/1236Z. Total IMF reached 16 nT at 15/0517Z. The maximum southward component of Bz reached -14 nT at 15/0517Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 152 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one and two (16 Dec, 17 Dec) and quiet levels on day three (18 Dec).

III. Event probabilities 16 Dec-18 Dec
Class M 25/20/15
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 15 Dec 103
Predicted 16 Dec-18 Dec 102/102/102
90 Day Mean 15 Dec 087

V. Geomagnetic A Indices
Observed Afr/Ap 14 Dec 004/004
Estimated Afr/Ap 15 Dec 009/011
Predicted Afr/Ap 16 Dec-18 Dec 008/008-008/008-006/005

VI. Geomagnetic Activity Probabilities 16 Dec-18 Dec
A. Middle Latitudes
Active 25/15/10
Minor Storm 05/05/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/25/20
Major-severe storm 30/25/20