From: Space Weather Prediction Center (NOAA)
Posted: Friday, September 8, 2017
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 251 Issued at 2200Z on 08 Sep 2017
IA. Analysis of Solar Active Regions and Activity from 07/2100Z to 08/2100Z: Solar activity has been at high levels for the past 24 hours. The largest solar event of the period was a M8 event observed at 08/0749Z from Region 2673 (S09W70). There are currently 5 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 and two (09 Sep, 10 Sep) and expected to be low with a chance for M-class flares and a slight chance for an X-class flare on day three (11 Sep).
IIA. Geophysical Activity Summary 07/2100Z to 08/2100Z: The geomagnetic field has been at active to severe storm levels for the past 24 hours. Solar wind speed reached a peak of 1110 km/s at 08/0431Z. Total IMF reached 34 nT at 07/2258Z. The maximum southward component of Bz reached -32 nT at 07/2257Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 844 pfu at 08/0035Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1941 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to major storm levels on day one (09 Sep) and quiet to unsettled levels on days two and three (10 Sep, 11 Sep). Protons are expected to cross threshold on day one (09 Sep), are likely to cross threshold on day two (10 Sep) and have a chance of crossing threshold on day three (11 Sep).
III. Event probabilities 09 Sep-11 Sep
Class M 75/75/50
Class X 50/50/20
IV. Penticton 10.7 cm Flux
Observed 08 Sep 117
Predicted 09 Sep-11 Sep 115/105/090
90 Day Mean 08 Sep 081
V. Geomagnetic A Indices
Observed Afr/Ap 07 Sep 023/042
Estimated Afr/Ap 08 Sep 053/098
Predicted Afr/Ap 09 Sep-11 Sep 022/030-007/010-007/008
VI. Geomagnetic Activity Probabilities 09 Sep-11 Sep
A. Middle Latitudes
Minor Storm 40/05/05
Major-severe storm 25/01/01
B. High Latitudes
Minor Storm 40/20/20
Major-severe storm 25/20/20
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