Forecaster summary - Issued 2025-09-21T00:12:54

GOES19 High energy (>2MeV) electron flux has been predominately High since 16 Sep, after the previous CME and coronal hole combined enhancement. This is expected to continue day 1 (21 Sep), with only very brief drop-outs possible before a more persistent drop out likely occurs from the onset of the fast winds of CH80/-, most likely either late day 1 (21 Sep) or day 2 (22 Sep). Any recovery in flux on days 3 and 4 (23-24 Sep) is expected to be subdued with only slight chance of reaching High at maximum

The associated 24 hr high energy fluence is expected to remain Active (>1e8 integrated pfu) , and above MOSWOC REFM expectations. REFM has a tendency to over-estimate the decline once solar winds have eased, and this is unlikely to occur until we see a further enhancement from the onset of the next feature. Due to this being a 24 hour total, the fluence is likely to remain above Active into day 2 (22 Sep) before quickly dropping off, and then likely remaining below Active days 3 and 4 (23-24 Sep).