Forecaster summary - Issued 2021-11-21T12:28:46

The high energy electron flux (greater than 2 MeV) as observed by GOES-16 at GEO has been at mainly Moderate levels, but may rise to High, especially during the diurnal observation peak. This is most likely to occur once any compression of the Van Allen belts from the current fast wind of CH20/- subsides later in this period, day 2 (22nd) onward. This will give a chance of 24-hour electron fluence exceeding Active later in the period, although confidence in this aspect is relatively low, especially due to the lack of a relevant analogue on last rotation.

MOSWOC REFM indicates an increasing risk of breaching Active in the next 72 hours, although the muted geomagnetic response to the fast wind suggests that this risk is lower than REFM signals, and perhaps delayed over its expectations. This potential is maintained in our forecast, although fluence levels are likely to remain below the Active threshold.