Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 10 September 2017

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 253 Issued at 2200Z on 10 Sep 2017

IA.  Analysis of Solar Active Regions and Activity from 09/2100Z to 10/2100Z: Solar activity has been at high levels for the past 24 hours. The largest solar event of the period was a X8 event observed at 10/1606Z from old Region 2673 (S09, L=119). There are currently 3 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 day one (11 Sep) and expected to be very low with a chance for a C-class flares and a slight chance for an M-class flare on day two (12 Sep) and expected to be very low with a slight chance for a C-class flare on day three (13 Sep).

IIA.  Geophysical Activity Summary 09/2100Z to 10/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 560 km/s at 10/1015Z. Total IMF reached 6 nT at 10/1935Z. The maximum southward component of Bz reached -4 nT at 10/2020Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 1038 pfu at 10/1845Z. Protons greater than 100 MeV at geosynchronous orbit reached a peak level of 54 pfu at 10/2100Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 7875 pfu.

IIB.  Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (11 Sep), quiet to active levels on day two (12 Sep) and unsettled to minor storm levels on day three (13 Sep). Protons are expected to cross threshold on day one (11 Sep), are expected to cross threshold on day two (12 Sep) and are likely to cross threshold on day three (13 Sep).

III.  Event probabilities 11 Sep-13 Sep
Class M    80/10/01
Class X    50/01/01
Proton     99/95/65
PCAF       red

IV.  Penticton 10.7 cm Flux
Observed           10 Sep 100
Predicted   11 Sep-13 Sep 085/083/081
90 Day Mean        10 Sep 081

V.  Geomagnetic A Indices
Observed Afr/Ap 09 Sep  006/004
Estimated Afr/Ap 10 Sep  005/006
Predicted Afr/Ap 11 Sep-13 Sep  007/007-010/012-020/030

VI.  Geomagnetic Activity Probabilities 11 Sep-13 Sep
A.  Middle Latitudes
Active                15/25/35
Minor Storm           05/10/25
Major-severe storm    01/01/05
B.  High Latitudes
Active                15/15/10
Minor Storm           20/30/25
Major-severe storm    20/40/60