Forecaster summary - Issued 2021-09-03T00:11:36

The high energy electron flux (greater than 2 MeV) as measured by GOES-16 at GEO has reached high levels over the past few days. It is likely that there will be a declining trend over the next 24 hours or so, but still with flux levels rising to high at the diurnal maximum. There are uncertainties thereafter, with further electron flux enhancement possible should solar wind speeds become elevated under weak coronal hole influences.

Associated electron fluence is forecast to be Active (above 1e8 integrated pfu) at first but slowly ease below the Active threshold by the end of day 2 (4th Sep). An increase later in the period could see a return to Active levels once again on Day 3 or 4 (5th or 6th Sep), but this is low confidence. REFM guidance will be of limited use during this forecast period, especially beyond T+24 when it becomes primarily persistence based.