Forecaster summary - Issued 2026-04-18T23:02:32

High energy (>2 MeV) electron flux at GOES19 is currently Background to Moderate, having dropped out after the onset of the fast winds of CH42/-. However, charging of the radiation belt is expected to occur as a consequence of this enhancement, with the observed flux at GEO increasing again from day 1 (19 Apr), and likely becoming persistently High, especially as solar winds ease later in the period. 

The associated 24 hour fluence was briefly above Active at the very start of the period on 18 Apr, but declined below Active in response to the drop out of flux. As flux recovers on day 1 (19 Apr), fluence will also rise, and is expected to become Active days 2-4 (20-22 Apr). This is supported by 27-day recurrence, although the onset is expected to be a little slower. MOSWOC REFM has yet to fully account for the fast wind onset, so is currently providing poor guidance. This will improve as the fast wind persists.