Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 31 December 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 365 Issued at 2200Z on 31 Dec 2015

IA. Analysis of Solar Active Regions and Activity from 30/2100Z to 31/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C4 event observed at 30/2245Z from Region 2473 (S21W60). There are currently 1 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is likely to be low with a slight chance for an M-class flare on days one and two (01 Jan, 02 Jan) and expected to be very low with a chance for a C-class flares on day three (03 Jan).

IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z: The geomagnetic field has been at quiet to major storm levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 575 km/s at 31/0537Z. Total IMF reached 17 nT at 31/1909Z. The maximum southward component of Bz reached -16 nT at 31/1915Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 883 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to major storm levels on day one (01 Jan) and unsettled to active levels on days two and three (02 Jan, 03 Jan). Protons greater than 10 Mev have a slight chance of crossing threshold on days one and two (01 Jan, 02 Jan).

III. Event probabilities 01 Jan-03 Jan
Class M 20/20/05
Class X 01/01/01
Proton 10/10/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 31 Dec 096
Predicted 01 Jan-03 Jan 095/100/100
90 Day Mean 31 Dec 109

V. Geomagnetic A Indices
Observed Afr/Ap 30 Dec 002/002
Estimated Afr/Ap 31 Dec 026/041
Predicted Afr/Ap 01 Jan-03 Jan 021/030-015/018-015/018

VI. Geomagnetic Activity Probabilities 01 Jan-03 Jan
A. Middle Latitudes
Active 35/30/30
Minor Storm 35/15/15
Major-severe storm 20/01/01
B. High Latitudes
Active 05/15/15
Minor Storm 20/30/30
Major-severe storm 75/45/45