Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 254 Issued at 2200Z on 11 Sep 2023

IA. Analysis of Solar Active Regions and Activity from 10/2100Z to 11/2100Z: Solar activity has been at moderate levels for the past 24 hours. The largest solar event of the period was a M1 event observed at 11/0128Z from Region 3429 (N10E46). There are currently 10 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is likely to be moderate with a slight chance for an X-class flare on days one, two, and three (12 Sep, 13 Sep, 14 Sep).

IIA. Geophysical Activity Summary 10/2100Z to 11/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed reached a peak of 429 km/s at 11/1902Z. Total IMF reached 8 nT at 11/0133Z. The maximum southward component of Bz reached -6 nT at 11/0038Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 174 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to active levels on days one and two (12 Sep, 13 Sep) and quiet to unsettled levels on day three (14 Sep). Protons greater than 10 Mev have a slight chance of crossing threshold on day three (14 Sep).

III. Event probabilities 12 Sep-14 Sep
Class M 55/55/55
Class X 10/10/10
Proton 05/05/10
PCAF green

IV. Penticton 10.7 cm Flux
Observed 11 Sep 176
Predicted 12 Sep-14 Sep 175/170/168
90 Day Mean 11 Sep 163

V. Geomagnetic A Indices
Observed Afr/Ap 10 Sep 006/003
Estimated Afr/Ap 11 Sep 007/007
Predicted Afr/Ap 12 Sep-14 Sep 011/015-011/012-009/010

VI. Geomagnetic Activity Probabilities 12 Sep-14 Sep
A. Middle Latitudes
Active 35/30/20
Minor Storm 10/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 25/25/15
Minor Storm 30/25/20
Major-severe storm 20/20/20

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