Forecaster summary - Issued 2021-10-11T00:12:27

The high energy (greater than 2 MeV) electron flux is currently at background levels. The arrival of the CME which left the Sun on 09 Oct is likely to keep flux levels at GEO suppressed through the early part of this period, as the radiation belts will be compressed by the increased wind speeds. However, these wind speeds are likely to drive an increase in electron flux, so as the CME effects wane and the radiation belts rebound a sharp increase in electron flux at GEO is possible. This is most likely to occur in the second half of the period, on Days 3 and 4 (13-14 Oct).

The electron fluence therefore is expected to stay below the Active (1e8 integrated pfu) threshold on Days 1 and 2 (11-12 Oct), with an increasing trend likely on Days 3 and 4. There is a chance of fluence reaching Active levels by the end of the period. Although REFM is indicating a continuation of very low fluence levels, it will not be taking account of any increase in wind speeds associated with the expected CME arrival. As such it is expected to be under forecasting fluence levels by the end of the period.