Forecaster summary - Issued 2025-09-04T00:23:09

High-energy (>2 MeV) electron flux observed by GOES-19 is at background and expected to persist mainly at this level until day 3 (06 Sep). Flux is then expected to rise as a response to the to the next coronal hole fast wind connection from  CH75+/CH76+, which likely occurred day 2 (05 Sep). Due to the polarity of these features being favoured at this time of year, this is likely to be a relatively strong connection, with flux rising to High later day 3 or into day 4 (06-07 Sep). 

The associated 24 hour fluence is expected to remain below the Active threshold through much of the period, but rising through day 3-4 (06-07 Sep) with a chance of rising above the Active threshold by the end of the period, although perhaps not until just beyond (08 Sep). REFM is currently over-estimating the expected flux. This is likely due to being driven from the recent solar wind speeds, including from the CME impact, despite this being a relatively subdued impact in relation to any geomagnetic activity.