Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 270 Issued at 2200Z on 27 Sep 2023
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 C4 event observed at 27/0546Z. There are currently 8 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 day one (28 Sep) and expected to be low with a chance for M-class flares on days two and three (29 Sep, 30 Sep).
IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 529 km/s at 26/2104Z. Total IMF reached 6 nT at 27/0456Z. The maximum southward component of Bz reached -4 nT at 27/1807Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3755 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one and two (28 Sep, 29 Sep) and quiet to active levels on day three (30 Sep). Protons greater than 10 Mev have a slight chance of crossing threshold on day one (28 Sep).
III. Event probabilities 28 Sep-30 Sep
Class M 35/30/30
Class X 10/05/05
Proton 10/05/05
PCAF green
IV. Penticton 10.7 cm Flux
Observed 27 Sep 156
Predicted 28 Sep-30 Sep 160/158/155
90 Day Mean 27 Sep 162
V. Geomagnetic A Indices
Observed Afr/Ap 26 Sep 026/032
Estimated Afr/Ap 27 Sep 014/016
Predicted Afr/Ap 28 Sep-30 Sep 007/008-007/008-010/012
VI. Geomagnetic Activity Probabilities 28 Sep-30 Sep
A. Middle Latitudes
Active 20/15/30
Minor Storm 05/05/10
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 20/20/30
Major-severe storm 20/20/40
Space weather
