Forecaster summary - Issued 2024-09-23T00:19:08

GOES-16 high energy electron flux has varied between Moderate and High, likely as a consequence of the outward expansion of the enhanced electron populations at lower orbits from the CME arrival on 16-17 Sep. Flux is expected to continue varying at this level though day 1-2, before the onset of any fast wind from coronal hole 72, most likely on day 3 (25 Sep). The subsequent increased solar wind pressure will likely compress the Van Allen belts, with a drop out in observed values then likely before a recovery on day 4 (26 Sep) as any initial geomagnetic activity subsides.

The associated 24 hour fluence subsequently reached the Active level, and is likely to persist at this level through day 1-2 (23-24 Sep). Confidence then falls day 3-4 (25-26 Dec) due to the likely drop out of flux due to any onset of any fast wind of CH72/+, in the centre disc. MOSWOC REFM also suggests a natural declining trend to the fluence, however this has been consistently underestimating the observed fluence reducing confidence in this model guidance.