Forecaster summary - Issued 2025-09-19T00:24:20

High energy (greater than 2MeV) electron flux as observed by GOES-19 became predominantly high through the 16 September due to fast wind onset and associated geomagnetic activity seeing an injection of high energy electrons. In the forecast absence of any further significant geomagnetic activity to influence the outer Van Allen Belts, electron flux is expected to remain predominantly high over the forecast period, although confidence reduces towards the end of the period and a slow depletion is possible. 

The associated 24 hour fluence is currently above the Active threshold. As moderate to high flux levels are expected through much of this period the general trend is expected to be relatively flat or slowly declining, although again confidence reduces with time. MOSWOC REFM is currently doing a good job with forecast fluence levels being close to the observed values. However, the 27-day recurrence is conversely under-estimating the likely fluence. Both however give a relatively flat trend over the coming days which is considered the most likely scenario.