Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 20 December 2016

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 355 Issued at 2200Z on 20 Dec 2016

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 2 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 380 km/s at 20/1910Z. Total IMF reached 9 nT at 20/1837Z. The maximum southward component of Bz reached -7 nT at 20/2051Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 345 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to minor storm levels on day one (21 Dec), active to minor storm levels on day two (22 Dec) and quiet to active 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 075
Predicted 21 Dec-23 Dec 075/075/080
90 Day Mean 20 Dec 081

V. Geomagnetic A Indices
Observed Afr/Ap 19 Dec 005/004
Estimated Afr/Ap 20 Dec 008/010
Predicted Afr/Ap 21 Dec-23 Dec 017/025-020/030-011/012

VI. Geomagnetic Activity Probabilities 21 Dec-23 Dec
A. Middle Latitudes
Active 40/40/25
Minor Storm 25/25/10
Major-severe storm 05/05/01
B. High Latitudes
Active 10/10/15
Minor Storm 25/25/25
Major-severe storm 60/60/35