Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 26 December 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 360 Issued at 2200Z on 26 Dec 2021

IA. Analysis of Solar Active Regions and Activity from 25/2100Z to 26/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C3 event observed at 26/2012Z. There are currently 5 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with
a slight chance for an M-class flare on days one, two, and three (27 Dec, 28 Dec, 29 Dec).

IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 541 km/s at 26/0304Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 2083 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on day one (27 Dec) and quiet to active levels on days two and three (28 Dec, 29 Dec).

III. Event probabilities 27 Dec-29 Dec
Class M 15/15/15
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 26 Dec 125
Predicted 27 Dec-29 Dec 125/125/122
90 Day Mean 26 Dec 092

V. Geomagnetic A Indices
Observed Afr/Ap 25 Dec 005/006
Estimated Afr/Ap 26 Dec 008/008
Predicted Afr/Ap 27 Dec-29 Dec 006/005-011/012-011/012

VI. Geomagnetic Activity Probabilities 27 Dec-29 Dec
A. Middle Latitudes
Active 15/35/35
Minor Storm 01/15/15
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 20/30/30
Major-severe storm 20/45/45