Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 23 December 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 357 Issued at 2200Z on 23 Dec 2021

IA. Analysis of Solar Active Regions and Activity from 22/2100Z to 23/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C2 event observed at 23/0930Z from Region 2907 (S22W65). 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 (24 Dec, 25 Dec, 26 Dec).

IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 585 km/s at 23/0316Z. Total IMF reached 5 nT at 23/0717Z. The maximum southward component of Bz reached -3 nT at 23/1739Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 2410 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to minor storm levels on day one (24 Dec) and quiet to unsettled levels on days two and three (25 Dec, 26 Dec). Protons have a slight chance of crossing threshold on days one, two, and three (24 Dec, 25 Dec, 26 Dec).

III. Event probabilities 24 Dec-26 Dec
Class M 25/25/25
Class X 10/10/10
Proton 10/10/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 23 Dec 130
Predicted 24 Dec-26 Dec 130/125/120
90 Day Mean 23 Dec 091

V. Geomagnetic A Indices
Observed Afr/Ap 22 Dec 008/008
Estimated Afr/Ap 23 Dec 009/013
Predicted Afr/Ap 24 Dec-26 Dec 016/020-010/012-014/016

VI. Geomagnetic Activity Probabilities 24 Dec-26 Dec
A. Middle Latitudes
Active 35/25/30
Minor Storm 25/05/10
Major-severe storm 05/01/01
B. High Latitudes
Active 10/15/15
Minor Storm 25/30/30
Major-severe storm 65/30/40