Forecaster summary - Issued 2025-09-08T00:18:18

High-energy (>2 MeV) electron flux observed by GOES-19 is expected to remain at mainly moderate levels through the early period, but with an increase to daily high levels possible mainly Days 2 to 4 (09-11 Sept) owing to reduced CME and coronal hole fast-wind influence. Confidence is lower than normal due to the irregular size of the large coronal hole on the disc and a stronger than expected connection to this feature later in the period could see lower electron counts sustained.

The associated electron fluence is forecast to remain below the Active threshold, but with a chance of exceeding this level on Day 3 and 4 (10 and 11 Sept). Latest MOSWOC REFM output is expected to over-forecast electron fluence as it does not recognise the recent CME arrival at Earth.