Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 260 Issued at 2200Z on 17 Sep 2023
IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C3 event observed at 17/1604Z from Region 3435 (N10E60). There are currently 5 numbered sunspot regions on the disk.
IB. Solar Activity Forecast: Solar activity is expected to be low with a slight chance for an M-class flare on days one, two, and three (18 Sep, 19 Sep, 20 Sep).
IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic field has been at unsettled to active levels for the past 24 hours. Solar wind speed reached a peak of 508 km/s at 17/0424Z. Total IMF reached 11 nT at 17/0412Z. The maximum southward component of Bz reached -8 nT at 17/0205Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 167 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (18 Sep), unsettled to major storm levels on day two (19 Sep) and quiet to active levels on day three (20 Sep).
III. Event probabilities 18 Sep-20 Sep
Class M 20/20/15
Class X 05/01/01
Proton 05/05/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 17 Sep 145
Predicted 18 Sep-20 Sep 145/140/140
90 Day Mean 17 Sep 162
V. Geomagnetic A Indices
Observed Afr/Ap 16 Sep 005/010
Estimated Afr/Ap 17 Sep 014/019
Predicted Afr/Ap 18 Sep-20 Sep 008/008-022/035-014/015
VI. Geomagnetic Activity Probabilities 18 Sep-20 Sep
A. Middle Latitudes
Active 20/25/25
Minor Storm 05/40/05
Major-severe storm 01/35/01
B. High Latitudes
Active 15/05/15
Minor Storm 25/20/20
Major-severe storm 35/75/25
Space Weather
