Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 352 Issued at 2200Z on 18 Dec 2022

IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity has been at low levels for the past 24 hours.

The largest solar event of the period was a C5 event observed at 18/1010Z from Region 3162 (S13W63). There are currently 8 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 (19 Dec, 20 Dec, 21 Dec).

IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 387 km/s at 17/2313Z. Total IMF reached 14 nT at 18/2059Z. The maximum southward component of Bz reached -7 nT at 18/2018Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 138 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and two (19 Dec, 20 Dec) and quiet to minor storm levels on day three (21 Dec). Protons have a slight chance of crossing threshold on days one, two, and three (19 Dec, 20 Dec, 21 Dec).

III. Event probabilities 19 Dec-21 Dec
Class M 30/30/30
Class X 10/10/10
Proton 10/10/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 18 Dec 156
Predicted 19 Dec-21 Dec 150/145/130
90 Day Mean 18 Dec 133

V. Geomagnetic A Indices
Observed Afr/Ap 17 Dec 002/002
Estimated Afr/Ap 18 Dec 004/005
Predicted Afr/Ap 19 Dec-21 Dec 011/012-008/010-017/020

VI. Geomagnetic Activity Probabilities 19 Dec-21 Dec
A. Middle Latitudes
Active 20/30/40
Minor Storm 05/10/25
Major-severe storm 01/01/05
B. High Latitudes
Active 15/15/15
Minor Storm 20/30/20
Major-severe storm 20/40/15

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