Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 354 Issued at 2200Z on 20 Dec 2022

IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: 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 20/1406Z from Region 3169 (N21E36). 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 and a slight chance for an X-class flare on days one, two, and three (21 Dec, 22 Dec, 23 Dec).

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 397 km/s at 20/1517Z. Total IMF reached 15 nT at 20/0744Z. The maximum southward component of Bz reached -9 nT at 20/2052Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 150 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to minor storm levels on day one (21 Dec), quiet to active levels on day two (22 Dec) and quiet levels on day three (23 Dec). Protons have a slight chance of crossing threshold on days one, two, and three (21 Dec, 22 Dec, 23 Dec).

III. Event probabilities 21 Dec-23 Dec
Class M 30/30/30
Class X 10/10/10
Proton 10/10/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 20 Dec 146
Predicted 21 Dec-23 Dec 140/135/125
90 Day Mean 20 Dec 133

V. Geomagnetic A Indices
Observed Afr/Ap 19 Dec 009/009
Estimated Afr/Ap 20 Dec 006/007
Predicted Afr/Ap 21 Dec-23 Dec 017/020-010/012-007/008

VI. Geomagnetic Activity Probabilities 21 Dec-23 Dec
A. Middle Latitudes
Active 40/25/15
Minor Storm 25/10/01
Major-severe storm 05/01/01
B. High Latitudes
Active 15/20/15
Minor Storm 20/25/15
Major-severe storm 15/20/10

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