Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 26 December 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 360 Issued at 2200Z on 26 Dec 2015

IA. Analysis of Solar Active Regions and Activity from 25/2100Z to 26/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C7 event observed at 26/0510Z from Region 2473 (S22E09). There are currently 2 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is likely to be moderate with a slight chance for an X-class flare on days one, two, and three (27 Dec, 28 Dec, 29 Dec).

IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 640 km/s at 26/2024Z. Total IMF reached 9 nT at 26/0123Z. The maximum southward component of Bz reached -6 nT at 26/1958Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3621 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to minor storm levels on day one (27 Dec), quiet to active levels on day two (28 Dec) and quiet to unsettled levels on day three (29 Dec). Protons greater than 10 Mev have a slight chance of crossing threshold on day three (29 Dec).

III. Event probabilities 27 Dec-29 Dec
Class M 55/55/55
Class X 10/10/10
Proton 05/05/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 26 Dec 117
Predicted 27 Dec-29 Dec 115/115/120
90 Day Mean 26 Dec 110

V. Geomagnetic A Indices
Observed Afr/Ap 25 Dec 006/006
Estimated Afr/Ap 26 Dec 012/017
Predicted Afr/Ap 27 Dec-29 Dec 014/016-009/012-007/010

VI. Geomagnetic Activity Probabilities 27 Dec-29 Dec
A. Middle Latitudes
Active 35/30/20
Minor Storm 20/10/05
Major-severe storm 05/01/01
B. High Latitudes
Active 10/15/15
Minor Storm 25/25/25
Major-severe storm 50/40/25