Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 31 August 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 243 Issued at 2200Z on 31 Aug 2017

IA.  Analysis of Solar Active Regions and Activity from 30/2100Z to 31/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C1 event observed at 30/2311Z from Region 2674 (N14E64). There are currently 4 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is likely to be low with a slight chance for an M-class flare on days one, two, and three (01 Sep, 02 Sep, 03 Sep).

IIA.  Geophysical Activity Summary 30/2100Z to 31/2100Z: The geomagnetic field has been at quiet to minor storm levels for the past 24 hours. Solar wind speed reached a peak of 719 km/s at 31/1217Z. Total IMF reached 31 nT at 31/0618Z. The maximum southward component of Bz reached -19 nT at 31/0539Z.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to minor storm levels on day one (01 Sep), quiet to active levels on day two (02 Sep) and quiet to unsettled levels on day three (03 Sep).

III.  Event probabilities 01 Sep-03 Sep
Class M    10/10/10
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           31 Aug 092
Predicted   01 Sep-03 Sep 092/092/091
90 Day Mean        31 Aug 077

V.  Geomagnetic A Indices
Observed Afr/Ap 30 Aug  005/005
Estimated Afr/Ap 31 Aug  025/034
Predicted Afr/Ap 01 Sep-03 Sep  016/024-015/016-012/012

VI.  Geomagnetic Activity Probabilities 01 Sep-03 Sep
A.  Middle Latitudes
Active                35/30/25
Minor Storm           35/10/10
Major-severe storm    10/01/01
B.  High Latitudes
Active                20/15/15
Minor Storm           20/20/20
Major-severe storm    20/20/20