Forecaster summary - Issued 2025-06-01T00:14:38

Electron flux increased to high levels throughout the UTC day, peaking at 9,160 pfu at 31/1620 UTC, driven by the continued fast solar wind enhancement associated with Coronal Hole 52 (CH52/-). The anticipated arrival of an Earth-directed coronal mass ejection (CME) on Day 1 (01 June) is expected to significantly disrupt the Van Allen radiation belts, leading to a depletion of trapped particles and a corresponding drop in electron flux.

An enhancement is likely to follow the initial depletion; however, it may take several days for the radiation belts to fully recover and for electron flux to return to high levels.

The associated 24-hour electron fluence is currently well above the "Active" threshold. Although a substantial decline is expected, values may remain elevated above the threshold on Day 2 (02 June). Confidence in this outlook is low, as it hinges entirely on the timing and impact of the CME. Additionally, the MOSWOC REFM model is expected to overestimate electron flux, as it does not account for the forecast CME influence.