Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 20 December 20020

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 355 Issued at 2200Z on 20 Dec 2020

IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 1 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be very low with a slight chance for a C-class flare on days one, two, and three (21 Dec, 22 Dec, 23 Dec).

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 416 km/s at 20/0901Z. Total IMF reached 6 nT at 19/2141Z. The maximum southward component of Bz reached -5 nT at 20/0407Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 227 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (21 Dec), quiet to unsettled levels on day two (22 Dec) and quiet to minor storm levels on day three (23 Dec).

III. Event probabilities 21 Dec-23 Dec
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 20 Dec 084
Predicted 21 Dec-23 Dec 084/084/084
90 Day Mean 20 Dec 083

V. Geomagnetic A Indices
Observed Afr/Ap 19 Dec 004/004
Estimated Afr/Ap 20 Dec 004/004
Predicted Afr/Ap 21 Dec-23 Dec 010/012-007/008-012/018

VI. Geomagnetic Activity Probabilities 21 Dec-23 Dec
A. Middle Latitudes
Active 30/20/35
Minor Storm 10/05/20
Major-severe storm 01/01/05
B. High Latitudes
Active 15/15/10
Minor Storm 30/25/25
Major-severe storm 40/25/55