Forecaster summary - Issued 2021-10-31T00:23:16

The high energy electron flux (greater than 2 MeV) as observed by GOES-16 at GEO is currently at background levels and expected to persist at this or moderate levels for much of the period. The still anticipated, but late arrival of the CME on day 1 (31st) has the potential to inject electrons into the Van Allen radiation belts. As geomagnetic activity subsides day 3 (1st) onward, the observed electron flux has the potential to increase to above the alert threshold (1000 pfu) although confidence is low. This will give a chance of reaching the Active fluence threshold (1e8 integrated pfu) from late day 2 onward (1st). REFM doesn't take account of the expected CME arrival, so whilst a good guide to current background conditions, will be of limited value when this arrives.