Forecaster summary - Issued 2021-07-27T00:02:06

The high energy electron flux (greater than 2MeV) is expected to be at mainly background to moderate levels until the arrival of the coronal hole fast wind from CH78 and CH79 late on day 1 (27th) and into day 2 (28th). With solar wind speeds of around 500 km/s, the probability of seeing an increasing electron population should be rather high. However, on the previous rotation, the Van Allen belts remained mainly at background levels during the whole period. A cautious approach is therefore advocated, suggesting any rise is most likely to be modest. 

Electron flux is therefore expected to increase to Moderate through day 2 (28th), potentially peaking at High levels during the diurnal cycle on days 3 and 4 (29th & 30th).   

The associated 24 hour electron fluence is expected to rise accordingly but stay below the Active threshold, with only a slight chance of rising above on days 3 and 4 (29th & 30th). REFM is giving good indication until at least the arrival of the fast wind on day 2 (29th), when fluence levels are likely to rise in response.