Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 27 December 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 361 Issued at 2200Z on 27 Dec 2015

IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C2 event observed at 27/1910Z from Region 2472 (N04W02). 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 (28 Dec, 29 Dec, 30 Dec).

IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at quiet to minor storm levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 620 km/s at 27/0140Z. Total IMF reached 7 nT at 26/2154Z. The maximum southward component of Bz reached -4 nT at 26/2106Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 7792 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (28 Dec) and quiet to unsettled levels on days two and three (29 Dec, 30 Dec). Protons greater than 10 Mev have a slight chance of crossing threshold on days two and three (29 Dec, 30 Dec).

III. Event probabilities 28 Dec-30 Dec
Class M 55/55/55
Class X 10/10/10
Proton 05/10/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 27 Dec 110
Predicted 28 Dec-30 Dec 110/110/110
90 Day Mean 27 Dec 110

V. Geomagnetic A Indices
Observed Afr/Ap 26 Dec 011/012
Estimated Afr/Ap 27 Dec 010/010
Predicted Afr/Ap 28 Dec-30 Dec 009/012-007/010-007/010

VI. Geomagnetic Activity Probabilities 28 Dec-30 Dec
A. Middle Latitudes
Active 30/20/20
Minor Storm 10/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 25/25/25
Major-severe storm 40/25/25