Forecaster summary - Issued 2025-10-27T12:37:08

GOES19 >10MeV electron flux has been at mostly moderate levels, and is likely to see a drop out to mainly background levels from any CME arrival on day 1 (26 Oct), and any subsequent fast wind enhancement days 2-3 (27-28 Oct).  While this may charge the Van Allen Belt, any subsequent rise in observed flux at GEO is most likely to occur either late day 3 or day 4 (28-29 Oct).
The associated 24 hr fluence is expected to remain below Active (<1e8 integrated pfu) initially, with a declining trend likely due to CME and HSS effects from 26-27 Oct. However, a subsequent rise is possible after the HSS sets in, bringing a chance of Active fluence by day 4 (29 Oct). Fluence rose above Active on the equivalent of day 4 during the previous rotation. At the present time MOSWOC REFM is not forecasting a rise in fluence, but it cannot yet take into account the
upcoming HSS, so it won't pick this up until after the onset of the HSS.