Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 351 Issued at 2200Z on 17 Dec 2022

IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: 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 17/1953Z from Region 3169 (N20E69). 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 (18 Dec, 19 Dec, 20 Dec).

IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 396 km/s at 17/0615Z. Total IMF reached 6 nT at 17/1841Z. The maximum southward component of Bz reached -2 nT at 17/0644Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 189 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one, two, and three (18 Dec, 19 Dec, 20 Dec). Protons have a slight chance of crossing threshold on days one, two, and three (18 Dec, 19 Dec, 20 Dec).

III. Event probabilities 18 Dec-20 Dec
Class M 50/50/50
Class X 10/10/10
Proton 10/10/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 17 Dec 155
Predicted 18 Dec-20 Dec 155/153/150
90 Day Mean 17 Dec 133

V. Geomagnetic A Indices
Observed Afr/Ap 16 Dec NA/003
Estimated Afr/Ap 17 Dec 002/003
Predicted Afr/Ap 18 Dec-20 Dec 009/010-006/008-007/008

VI. Geomagnetic Activity Probabilities 18 Dec-20 Dec
A. Middle Latitudes
Active 15/05/15
Minor Storm 05/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 20/15/25
Major-severe storm 20/10/20

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