- Press Release
- Dec 4, 2022
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 27 September 2017
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 270 Issued at 2200Z on 27 Sep 2017
IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: 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 27/0101Z from Region 2683 (N13E46). There are currently 3 numbered sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be very low with a chance for a C-class flares on days one, two, and three (28 Sep, 29 Sep, 30 Sep).
IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at quiet to major storm levels for the past 24 hours. Solar wind speed reached a peak of 714 km/s at 27/2040Z. Total IMF reached 17 nT at 27/0640Z. The maximum southward component of Bz reached -16 nT at 27/0640Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 126 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at active to major storm levels on day one (28 Sep), unsettled to minor storm levels on day two (29 Sep) and quiet to active levels on day three (30 Sep).
III. Event probabilities 28 Sep-30 Sep
Class M 01/01/01
Class X 01/01/01
IV. Penticton 10.7 cm Flux
Observed 27 Sep 091
Predicted 28 Sep-30 Sep 091/091/091
90 Day Mean 27 Sep 082
V. Geomagnetic A Indices
Observed Afr/Ap 26 Sep 003/004
Estimated Afr/Ap 27 Sep 022/030
Predicted Afr/Ap 28 Sep-30 Sep 024/032-020/026-011/014
VI. Geomagnetic Activity Probabilities 28 Sep-30 Sep
A. Middle Latitudes
Minor Storm 40/30/10
Major-severe storm 10/05/01
B. High Latitudes
Minor Storm 20/20/25
Major-severe storm 80/60/40