Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 21 December 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 355 Issued at 2200Z on 21 Dec 2015

IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity has been at moderate levels for the past 24 hours. The largest solar event of the period was a M2 event observed at 21/0103Z from Region 2472 (N04E78). There are currently 3 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares on days one, two, and three (22 Dec, 23 Dec, 24 Dec).

IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: 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 452 km/s at 21/0036Z. Total IMF reached 19 nT at 20/2231Z. The maximum southward component of Bz reached -18 nT at 20/2210Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1545 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (22 Dec) and quiet levels on days two and three (23 Dec, 24 Dec).

III. Event probabilities 22 Dec-24 Dec
Class M 25/25/25
Class X 05/05/05
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 21 Dec 122
Predicted 22 Dec-24 Dec 125/130/130
90 Day Mean 21 Dec 109

V. Geomagnetic A Indices
Observed Afr/Ap 20 Dec 033/068
Estimated Afr/Ap 21 Dec 025/040
Predicted Afr/Ap 22 Dec-24 Dec 011/010-006/006-006/005

VI. Geomagnetic Activity Probabilities 22 Dec-24 Dec
A. Middle Latitudes
Active 15/10/10
Minor Storm 05/01/05
Major-severe storm 01/01/01
B. High Latitudes
Active 20/15/15
Minor Storm 30/25/25
Major-severe storm 20/10/20