Forecaster summary - Issued 2025-04-08T00:11:41

High energy electron flux (greater than 2MeV) as observed at GEO has been persistently High after the recent fast wind connection to CH27. The switch of primary observation source, from GOES16 to GOES-19, occurred around peak on 07 Apr, resulting in a notable jump in the observed flux, from around 12000pfu to over 17000pfu. 

Ongoing fast winds are expected at first, however there is the potential for further fast wind onsets, and subsequent geomagnetic activity through the period. These are most likely to occur through day 2 (09 Apr) due to CH31 or later day 3 and day 4 (10-11 Apr) due to CH29. Any such connections, and the subsequent increased solar wind pressure and geomagnetic activity, are likely to reduce the flux to Moderate, or potentially Background for a time, with a more subdued recovery then likely. Otherwise, High flux is expected to continue. 

The associated 24h fluence is currently Active, and expected to persist at this level though days 1-2 (08-09 Apr). Given the change of instrumentation, the ongoing High flux, and the potential for further increases on day 1 (08 Apr), a slight chance of reaching Very Active (1e9 integrated pfu) is accounted for given the high peak observed by GOES-19 on 07 Apr. Confidence then decreases day 3-4 with the potential for any further coronal hole sourced enhancements to limit the observed flux at GEO, along with a likely natural decay, inline with current MOSWOC REFM and 27-day persistence trend. Although REFM is currently over-estimating the likely peak fluence in the next 24 hours