Forecaster summary - Issued 2026-04-20T00:10:13

High energy (>2 MeV) electron flux at GOES19 is currently Moderate to High levels, during its diurnal cycle. However, charging of the radiation belt is expected to occur as a consequence of the recent high speed stream arrival from CH42/-, with the observed flux at GEO becoming persistently High, especially as solar winds ease later in the period. 

The associated 24 hour fluence was at Normal Background levels. As flux recovers on day 1 (20 Apr), fluence will also rise, and is expected to become Active days 1-4 (20-23 Apr). This is supported by 27-day recurrence, although the onset is expected to be a little slower. MOSWOC REFM has now accounted for the fast wind onset, so is currently providing reasonable guidance.