Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 27 December 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 361 Issued at 2200Z on 27 Dec 2017

IA.  Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: 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 (28 Dec, 29 Dec, 30 Dec).

IIA.  Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 491 km/s at 26/2250Z. Total IMF reached 9 nT at 27/1621Z. The maximum southward component of Bz reached -7 nT at 27/1907Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1810 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (28 Dec) and quiet levels on days two and three (29 Dec, 30 Dec).

III.  Event probabilities 28 Dec-30 Dec
Class M    01/01/01
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           27 Dec 071
Predicted   28 Dec-30 Dec 071/070/070
90 Day Mean        27 Dec 074

V.  Geomagnetic A Indices
Observed Afr/Ap 26 Dec  008/009
Estimated Afr/Ap 27 Dec  007/007
Predicted Afr/Ap 28 Dec-30 Dec  007/006-005/005-006/005

VI.  Geomagnetic Activity Probabilities 28 Dec-30 Dec
A.  Middle Latitudes
Active                15/10/10
Minor Storm           05/05/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                20/15/15
Minor Storm           20/15/15
Major-severe storm    20/15/10