- Press Release
- Dec 6, 2022
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 21 September 2017
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 264 Issued at 2200Z on 21 Sep 2017
IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 2 numbered sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be very low with a slight chance for a C-class flare on day one (22 Sep) and likely to be low with a slight chance for an M-class flare on days two and three (23 Sep, 24 Sep).
IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 472 km/s at 21/0212Z. Total IMF reached 5 nT at 21/2058Z. The maximum southward component of Bz reached -4 nT at 21/1723Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 30386 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on day one (22 Sep), quiet to unsettled levels on day two (23 Sep) and quiet to active levels on day three (24 Sep).
III. Event probabilities 22 Sep-24 Sep
Class M 01/15/15
Class X 01/01/01
IV. Penticton 10.7 cm Flux
Observed 21 Sep 073
Predicted 22 Sep-24 Sep 070/085/090
90 Day Mean 21 Sep 081
V. Geomagnetic A Indices
Observed Afr/Ap 20 Sep 008/009
Estimated Afr/Ap 21 Sep 007/007
Predicted Afr/Ap 22 Sep-24 Sep 006/005-007/008-009/012
VI. Geomagnetic Activity Probabilities 22 Sep-24 Sep
A. Middle Latitudes
Minor Storm 01/05/10
Major-severe storm 01/01/01
B. High Latitudes
Minor Storm 20/25/25
Major-severe storm 15/30/40