Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 13 December 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 347 Issued at 2200Z on 13 Dec 2021

IA. Analysis of Solar Active Regions and Activity from 12/2100Z to 13/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C1 event observed at 12/2114Z. There are currently 3 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be very low with a slight chance for a C-class flare on days one, two, and three (14 Dec, 15 Dec, 16 Dec).

IIA. Geophysical Activity Summary 12/2100Z to 13/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed reached a peak of 336 km/s at 13/0704Z. Total IMF reached 9 nT at 13/0818Z. The maximum southward component of Bz reached -6 nT at13/0122Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 354 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected

to be at quiet to unsettled levels on days one and three (14 Dec, 16
Dec) and quiet to active levels on day two (15 Dec).

III. Event probabilities 14 Dec-16 Dec
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 13 Dec 081
Predicted 14 Dec-16 Dec 082/082/084
90 Day Mean 13 Dec 086

V. Geomagnetic A Indices
Observed Afr/Ap 12 Dec 002/002
Estimated Afr/Ap 13 Dec 007/006
Predicted Afr/Ap 14 Dec-16 Dec 007/008-010/012-007/008

VI. Geomagnetic Activity Probabilities 14 Dec-16 Dec
A. Middle Latitudes
Active 15/30/25
Minor Storm 01/10/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 25/30/30
Major-severe storm 20/40/30