Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 6 September 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 249 Issued at 2200Z on 06 Sep 2017

IA.  Analysis of Solar Active Regions and Activity from 05/2100Z to 06/2100Z: Solar activity has been at high levels for the past 24 hours. The largest solar event of the period was a X9 event observed at 06/1202Z from Region 2673 (S09W45). There are currently 4 numbered sunspot regions on the disk.

IB.  Solar Activity Forecast: Solar activity is expected to be moderate with a chance for X-class flares on days one, two, and three (07 Sep, 08 Sep, 09 Sep).

IIA.  Geophysical Activity Summary 05/2100Z to 06/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 494 km/s at 06/0259Z. Total IMF reached 5 nT at 06/0136Z. The maximum southward component of Bz reached -2 nT at 06/1325Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 155 pfu at 05/2100Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 7224 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to severe storm levels on day one (07 Sep) and active to severe storm levels on days two and three (08 Sep, 09 Sep). Protons are expected to cross threshold on day one (07 Sep), have a chance of crossing threshold on day two (08 Sep) and have a slight chance of crossing threshold on day three (09 Sep).

III.  Event probabilities 07 Sep-09 Sep
Class M    75/75/75
Class X    50/50/50
Proton     85/25/15
PCAF       red

IV.  Penticton 10.7 cm Flux
Observed           06 Sep 133
Predicted   07 Sep-09 Sep 135/135/135
90 Day Mean        06 Sep 080

V.  Geomagnetic A Indices
Observed Afr/Ap 05 Sep  011/011
Estimated Afr/Ap 06 Sep  019/037
Predicted Afr/Ap 07 Sep-09 Sep  032/045-035/052-031/045

VI.  Geomagnetic Activity Probabilities 07 Sep-09 Sep
A.  Middle Latitudes
Active                15/15/15
Minor Storm           35/35/35
Major-severe storm    50/50/50
B.  High Latitudes
Active                15/10/10
Minor Storm           35/20/25
Major-severe storm    45/55/60