Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 355 Issued at 2200Z on 21 Dec 2022

IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity has been at low levels for the past 24 hours.

The largest solar event of the period was a C7 event observed at 21/0621Z from Region 3169 (N19E19). There are currently 6 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 and two (22 Dec, 23 Dec) and expected to be low with a slight chance for an M-class flare on day three (24 Dec).

IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 518 km/s at 20/2108Z. Total IMF reached 15 nT at 21/0748Z. The maximum southward component of Bz reached -11 nT at 21/0609Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 139 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (22 Dec), quiet to unsettled levels on day two (23 Dec) and quiet levels on day three (24 Dec). Protons greater than 10 Mev have a slight chance of crossing threshold on days one and two (22 Dec, 23 Dec).

III. Event probabilities 22 Dec-24 Dec
Class M 30/30/20
Class X 10/10/05
Proton 10/10/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 21 Dec 139
Predicted 22 Dec-24 Dec 140/135/130
90 Day Mean 21 Dec 133

V. Geomagnetic A Indices
Observed Afr/Ap 20 Dec 005/005
Estimated Afr/Ap 21 Dec 010/013
Predicted Afr/Ap 22 Dec-24 Dec 010/012-008/008-006/005

VI. Geomagnetic Activity Probabilities 22 Dec-24 Dec
A. Middle Latitudes
Active 25/15/10
Minor Storm 10/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 20/15/15
Minor Storm 25/15/15
Major-severe storm 20/10/10

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