Forecaster summary - Issued 2022-12-27T01:30:26

High energy electron flux (greater than 2MeV) has been following a declining trend through the last six hours, having previously been at high levels prior to the recent geomagnetic storming. This is likely to be part of diurnal variation, exacerbated by the recent G1/Minor Storms. This trend of moderate to high (1e3 pfu) levels of electron flux are likely during 27 and 28 December in the absence of significant geomagnetic activity, which could distort the belts and redistribute electrons away from the radiation belts. The likely onset of a high speed stream from coronal hole 59 on 29 December may initially distort the belts, leading to an observed reduction in electron counts at GEO, which may then continue through into 30 December, depending on the strength of the high speed stream.

Electron fluence is following a slight downward trend, with this expected to continue through 27 December in a more muted electron flux environment compared to the previous 24 hours. The remaining of the forecast period is subject to the caveats mentioned above, with the likelihood of increased geomagnetic activity and belt distortion biasing the forecast to a lower likelihood of exceeding the Active (1e8 integrated pfu) threshold through the next three days, with a slight increase then possible on 30 December.