Forecaster summary - Issued 2025-04-18T00:11:08

High energy electron flux (greater than 2MeV) has been at mostly moderate levels during the last 24 hours, following the arrival of the CME on 15 April. It is possible that the recent CME effects have increased electron flux below GEO, with the Van Allen belts compressed by the CME. Now that CME effects are starting to wane, any increase in electron flux is likely to show itself at GEO over the next day or two, with the possibility of reaching high flux levels in the coming days. However, the potential arrival of a HSS from CH34, probably on Day 4 (21 Apr - see Geomagnetic Storm section for discussion on timing uncertainties), is likely to suppress electron flux at least temporarily.

The associated 24 hour fluence is currently below Active (1e8 integrated pfu) on a steady trend. A rise in fluence is probable over the next few days, with a chance of reaching Active by Day 3 (20 Apr), then a decline is likely on Day 4. MOSWOC REFM is not indicating a rise, however, so confidence here is low.