- Nov 13, 2023
Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 268 Issued at 2200Z on 25 Sep 2023
IA. Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C9 event observed at 25/0813Z from Region 3445 (S14W09). There are currently 10 numbered sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares and a slight chance for an X-class flare on days one, two, and three (26 Sep, 27 Sep, 28 Sep).
IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic field has been at quiet to major storm levels for the past 24 hours. Solar wind speed reached a peak of 508 km/s at 25/0445Z. Total IMF reached 34 nT at 25/1008Z. The maximum southward component of Bz reached -18 nT at 25/0046Z.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to minor storm levels on day one (26 Sep), quiet to unsettled levels on day two (27 Sep) and quiet levels on day three (28 Sep). Protons have a slight chance of crossing threshold on days one, two, and three (26 Sep, 27 Sep, 28 Sep).
III. Event probabilities 26 Sep-28 Sep
Class M 40/40/45
Class X 15/15/15
IV. Penticton 10.7 cm Flux
Observed 25 Sep 170
Predicted 26 Sep-28 Sep 166/164/164
90 Day Mean 25 Sep 162
V. Geomagnetic A Indices
Observed Afr/Ap 24 Sep 017/024
Estimated Afr/Ap 25 Sep 019/026
Predicted Afr/Ap 26 Sep-28 Sep 016/024-009/010-005/005
VI. Geomagnetic Activity Probabilities 26 Sep-28 Sep
A. Middle Latitudes
Minor Storm 25/05/05
Major-severe storm 05/01/01
B. High Latitudes
Minor Storm 20/20/15
Major-severe storm 30/20/15