Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 25 December 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 359 Issued at 2200Z on 25 Dec 2015

IA. Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C6 event observed at 25/1729Z from Region 2472 (N03E23). There are currently 4 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 and two (26 Dec, 27 Dec) and expected to be low with a chance for M-class flares on day three (28 Dec).

IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: 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 583 km/s at 25/0524Z. Total IMF reached 9 nT at 25/1653Z. The maximum southward component of Bz reached -8 nT at 25/1942Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3732 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and three (26 Dec, 28 Dec) and quiet to unsettled levels on day two (27 Dec).

III. Event probabilities 26 Dec-28 Dec
Class M 45/45/40
Class X 10/10/05
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 25 Dec 126
Predicted 26 Dec-28 Dec 125/125/120
90 Day Mean 25 Dec 110

V. Geomagnetic A Indices
Observed Afr/Ap 24 Dec 008/008
Estimated Afr/Ap 25 Dec 009/010
Predicted Afr/Ap 26 Dec-28 Dec 012/012-007/008-009/012

VI. Geomagnetic Activity Probabilities 26 Dec-28 Dec
A. Middle Latitudes
Active 25/15/30
Minor Storm 05/05/10
Major-severe storm 01/01/01
B. High Latitudes
Active 20/15/15
Minor Storm 30/25/30
Major-severe storm 30/20/40