Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 22 December 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 356 Issued at 2200Z on 22 Dec 2021

IA. Analysis of Solar Active Regions and Activity from 21/2100Z to 22/2100Z: 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 22/0706Z from Region 2908 (S20W39). There are currently 9 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares and a slight chance for an X-class flare on days one, two, and three (23 Dec, 24 Dec, 25 Dec).

IIA. Geophysical Activity Summary 21/2100Z to 22/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 604 km/s at 22/1215Z. Total IMF reached 6 nT at 22/0104Z. The maximum southward component of Bz reached -4 nT at 22/0230Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1189 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected quiet to unsettled levels on day three (25 Dec). Protons have a slight chance of crossing threshold on days one, two, and three (23 Dec, 24 Dec, 25 Dec).

III. Event probabilities 23 Dec-25 Dec
Class M 25/25/25
Class X 10/10/10
Proton 10/10/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 22 Dec 140
Predicted 23 Dec-25 Dec 140/140/138
90 Day Mean 22 Dec 090

V. Geomagnetic A Indices
Observed Afr/Ap 21 Dec 007/008
Estimated Afr/Ap 22 Dec 011/012
Predicted Afr/Ap 23 Dec-25 Dec 012/016-016/020-009/008

VI. Geomagnetic Activity Probabilities 23 Dec-25 Dec
A. Middle Latitudes
Active 35/35/20
Minor Storm 20/25/05
Major-severe storm 05/05/01
B. High Latitudes
Active 10/10/15
Minor Storm 25/25/25
Major-severe storm 55/65/30