Forecaster summary - Issued 2021-08-31T00:17:39

The high energy electron flux (greater than 2 MeV) as measured by GOES-16 at GEO is expected to start at high levels in the wake of recent weak CME influences, but with a general trend to moderate levels on day 1 (31st). There are uncertainties thereafter, with temporary electron re-distribution likely, associated with increased geomagnetic activity from a CME arrival late day 1 or on day 2 (1st). There is the added complication of further possible CME effects on day 3 (2nd). In the wake of any further CME effects, electron counts would be expected to rise to moderate to high levels again.

The associated 24 hour fluence is currently active, with a decreasing trend and likely to fall below the active threshold by day 2. Any re-enhancement is low confidence at this stage, and heavily dependent on any increased electron counts in the wake of any CME activity. REFM guidance will be of limited use during this forecast period, especially beyond T+24 when it becomes primarily persistence based.