Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 20 August 2015

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 232 Issued at 2200Z on 20 Aug 2015

IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C3 event observed at 20/0526Z from Region 2403 (S13E37). There are currently 3 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with a slight chance for an M-class flare on days one, two, and three (21 Aug, 22 Aug, 23 Aug).

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 566 km/s at 20/0813Z. Total IMF reached 7 nT at 20/1140Z. The maximum southward component of Bz reached -6 nT at 20/1049Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 8392 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and two (21 Aug, 22 Aug) and unsettled to minor storm levels on day three (23 Aug).

III. Event probabilities 21 Aug-23 Aug
Class M 15/15/15
Class X 05/05/05
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 20 Aug 103
Predicted 21 Aug-23 Aug 105/110/115
90 Day Mean 20 Aug 110

V. Geomagnetic A Indices
Observed Afr/Ap 19 Aug 018/019
Estimated Afr/Ap 20 Aug 009/013
Predicted Afr/Ap 21 Aug-23 Aug 010/012-009/012-021/028

VI. Geomagnetic Activity Probabilities 21 Aug-23 Aug
A. Middle Latitudes
Active 30/25/45
Minor Storm 05/05/25
Major-severe storm 01/01/05
B. High Latitudes
Active 15/20/05
Minor Storm 35/35/25
Major-severe storm 40/30/70