Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 29 September 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 272 Issued at 2200Z on 29 Sep 2021

IA. Analysis of Solar Active Regions and Activity from 28/2100Z to 29/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C1 event observed at29/0218Z from Region 2880 (N29E43). There are currently 5 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares on days one, two, and three (30 Sep, 01 Oct, 02 Oct).

IIA. Geophysical Activity Summary 28/2100Z to 29/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 499 km/s at 28/2147Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 449 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (30 Sep), quiet to minor storm levels on day two (01 Oct) and quiet to unsettled levels on day three (02 Oct).

III. Event probabilities 30 Sep-02 Oct
Class M 25/25/25
Class X 05/05/05
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 29 Sep 102
Predicted 30 Sep-02 Oct 100/105/110
90 Day Mean 29 Sep 082

V. Geomagnetic A Indices
Observed Afr/Ap 28 Sep 009/009
Estimated Afr/Ap 29 Sep 005/006
Predicted Afr/Ap 30 Sep-02 Oct 011/012-018/024-008/010

VI. Geomagnetic Activity Probabilities 30 Sep-02 Oct
A. Middle Latitudes
Active 35/45/30
Minor Storm 10/30/15
Major-severe storm 01/05/01
B. High Latitudes
Active 15/05/15
Minor Storm 30/20/30
Major-severe storm 45/70/45