Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 20 December 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 354 Issued at 2200Z on 20 Dec 2017

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 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 to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 505 km/s at 19/2200Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 4134 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on day one (21 Dec) and quiet to unsettled levels on days two and three (22 Dec, 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 074
Predicted   21 Dec-23 Dec 075/075/075
90 Day Mean        20 Dec 075

V.  Geomagnetic A Indices
Observed Afr/Ap 19 Dec  004/003
Estimated Afr/Ap 20 Dec  006/006
Predicted Afr/Ap 21 Dec-23 Dec  005/005-007/008-008/008

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