Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 28 December 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 362 Issued at 2200Z on 28 Dec 2015

IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity has been at moderate levels for the past 24 hours. The largest solar event of the period was an M1 event observed at 28/1245Z from Region 2473 (S22W19). There are currently 2 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares and a slight chance for an X-class flare on days one, two, and three (29 Dec, 30 Dec, 31 Dec).

IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 548 km/s at 27/2300Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1832 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (29 Dec), quiet to major storm levels on day two (30 Dec) and unsettled to minor storm levels on day three (31 Dec). Protons have a slight chance of crossing threshold on days one, two, and three (29 Dec, 30 Dec, 31 Dec).

III. Event probabilities 29 Dec-31 Dec
Class M 50/50/50
Class X 10/10/10
Proton 10/10/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 28 Dec 112
Predicted 29 Dec-31 Dec 110/110/110
90 Day Mean 28 Dec 109

V. Geomagnetic A Indices
Observed Afr/Ap 27 Dec 007/006
Estimated Afr/Ap 28 Dec 007/007
Predicted Afr/Ap 29 Dec-31 Dec 008/010-021/032-015/026

VI. Geomagnetic Activity Probabilities 29 Dec-31 Dec
A. Middle Latitudes
Active 20/40/40
Minor Storm 05/25/20
Major-severe storm 01/05/05
B. High Latitudes
Active 15/10/10
Minor Storm 25/25/25
Major-severe storm 25/60/60