Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 25 December 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 359 Issued at 2200Z on 25 Dec 2017

IA.  Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: 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 (26 Dec, 27 Dec, 28 Dec).

IIA.  Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 570 km/s at 24/2104Z. Total IMF reached 8 nT at 25/2009Z. The maximum southward component of Bz reached -6 nT at 25/2008Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 237 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (26 Dec) and quiet levels on days two and three (27 Dec, 28 Dec).

III.  Event probabilities 26 Dec-28 Dec
Class M    01/01/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           25 Dec 076
Predicted   26 Dec-28 Dec 075/075/074
90 Day Mean        25 Dec 074

V.  Geomagnetic A Indices
Observed Afr/Ap 24 Dec  009/008
Estimated Afr/Ap 25 Dec  010/011
Predicted Afr/Ap 26 Dec-28 Dec  007/008-006/005-005/005

VI.  Geomagnetic Activity Probabilities 26 Dec-28 Dec
A.  Middle Latitudes
Active                15/15/10
Minor Storm           05/05/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           25/20/15
Major-severe storm    25/20/10