Forecaster summary - Issued 2023-09-12T00:30:07

High energy (greater than 2 MeV) electron flux observed by GOES-16 is expected to remain at background day 1 (12 Sep). Any coronal hole fast wind arrival from CH44/+ has the potential to increase the flux through the Van Allen belts, and observed values at GEO are likely to increase later day1 or more likely day 2 (12-13 Sep), rising to Moderate, perhaps High at diurnal peak. However this rise is low confidence, with the potential for further solar wind enhancement to disrupt the belts, and lead to a drop out in observed flux. This is most likely to occur day 3 (14 Sep), before a recovery to Moderate on day 4 (15 Sep).

The associated 24-hour fluence will most likely remain below the Active (1e8 integrated pfu) threshold. Confidence for this decreases day 2 onward, with a slight chance of rising above, depending on both the strength of the initial enhancement from CH44, but also the length of time until any drop out occurs from any subsequent enhancement. MOSWOC REFM is considered to be giving good guidance until the onset of any fast winds.