Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 263 Issued at 2200Z on 20 Sep 2023

IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: Solar activity has been at high levels for the past 24 hours. The largest solar event of the period was a M8 event observed at 20/1419Z from Region 3435 (N09E29). There are currently 11 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is likely to be moderate on days one, two, and three (21 Sep, 22 Sep, 23 Sep).

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 567 km/s at 19/2211Z. Total IMF reached 10 nT at 20/0548Z. The maximum southward component of Bz reached -4 nT at 20/0859Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 2923 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one and three (21 Sep, 23 Sep) and quiet to active levels on day two (22 Sep).

III. Event probabilities 21 Sep-23 Sep
Class M 55/55/55
Class X 05/05/05
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 20 Sep 156
Predicted 21 Sep-23 Sep 155/152/153
90 Day Mean 20 Sep 161

V. Geomagnetic A Indices
Observed Afr/Ap 19 Sep 038/038
Estimated Afr/Ap 20 Sep 012/016
Predicted Afr/Ap 21 Sep-23 Sep 008/008-011/015-011/012

VI. Geomagnetic Activity Probabilities 21 Sep-23 Sep
A. Middle Latitudes
Active 20/35/30
Minor Storm 05/15/15
Major-severe storm 01/01/01
B. High Latitudes
Active 15/10/10
Minor Storm 20/30/25
Major-severe storm 20/50/50

space weather