Forecaster summary - Issued 2026-06-10T00:29:35

The GOES19 high-energy (>2MeV) electron flux has been moderate to high over the last few days in response to the recent CME and fast wind arrivals. As the CME arrival on the 09 June was very weak, there is a likelihood electrons may continue at moderate to high levels. The next mechanism likely to cause a drop-out of electron flux at GEO will be the onset of coronal hole fast winds from late Day 3 (11 June). However, through Day 4 (13 Jun) as the HSS eases so the electron count is expected to rebound, potentially reaching High levels.

As electron flux levels are now expected to remain moderate to high until the HSS arrival, and the associated fluence is already close to the Active (1e8 integrated flux) threshold, there is a chance of Active fluence conditions during Day 1-2 (10-11 Jun), and again through Day 4 (13 Jun). The REFM model is considered to be giving reasonable guidance, keeping the fluence below Active, despite the initial poor representation of fluence levels.