Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 22 September 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 265 Issued at 2200Z on 22 Sep 2021

IA. Analysis of Solar Active Regions and Activity from 21/2100Z to 22/2100Z: Solar activity has been at very low levels for the past 24 hours. There are currently 5 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is likely to be low with a slight chance for an M-class flare on days one, two, and three (23 Sep, 24 Sep, 25 Sep).

IIA. Geophysical Activity Summary 21/2100Z to 22/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 412 km/s at 22/1157Z. Total IMF reached 10 nT at 21/2317Z. The maximum southward component of Bz reached -8 nT at 21/2315Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 149 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on day one (23 Sep) and quiet to unsettled levels on days two and three (24 Sep, 25 Sep).

III. Event probabilities 23 Sep-25 Sep
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 22 Sep 089
Predicted 23 Sep-25 Sep 090/095/095
90 Day Mean 22 Sep 082

V. Geomagnetic A Indices
Observed Afr/Ap 21 Sep 006/006
Estimated Afr/Ap 22 Sep 011/013
Predicted Afr/Ap 23 Sep-25 Sep 008/012-007/008-013/015

VI. Geomagnetic Activity Probabilities 23 Sep-25 Sep
A. Middle Latitudes
Active 30/20/35
Minor Storm 10/05/15
Major-severe storm 01/01/01
B. High Latitudes
Active 15/20/15
Minor Storm 25/30/30
Major-severe storm 40/25/50