Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 19 December 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 353 Issued at 2200Z on 19 Dec 2021

IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: 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 19/1916Z from Region 2907 (S21W14). There are currently 7 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with a slight chance for an M-class flare on days one, two, and three (20 Dec, 21 Dec, 22 Dec).

IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 461 km/s at 19/2051Z. Total IMF reached 23 nT at 19/2034Z. The maximum southward component of Bz reached -20 nT at 19/2038Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 477 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one, two, and three (20 Dec, 21 Dec, 22 Dec).

III. Event probabilities 20 Dec-22 Dec
Class M 20/20/20
Class X 05/05/05
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 19 Dec 115
Predicted 20 Dec-22 Dec 115/115/114
90 Day Mean 19 Dec 089

V. Geomagnetic A Indices
Observed Afr/Ap 18 Dec 002/002
Estimated Afr/Ap 19 Dec 007/010
Predicted Afr/Ap 20 Dec-22 Dec 010/012-012/016-010/012

VI. Geomagnetic Activity Probabilities 20 Dec-22 Dec
A. Middle Latitudes
Active 25/30/25
Minor Storm 05/15/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/30/30
Major-severe storm 30/45/30