Forecaster summary - Issued 2019-06-02T00:15:28

The high energy electron flux (greater than 2MeV) is expected be mainly at high levels at first, although falling to moderate briefly due to the diurnal variation. Despite this, peak values are expected to gradually fall through the period, with the flux becoming mostly moderate by day 4. This is due to the natural decay of high flux values in the ambient solar wind environment that is anticipated.

The Active 24-hour fluence levels are therefore expected to persist, peaking early day 1 before showing a gradual decline. Whilst this decline is indicated by both persistence and REFM expectations, these are both considered to be reducing electron counts too quickly, unless a period of slightly enhanced geomagnetic activity was to occur. As this is currently seen as a relatively low chance, fluence levels are currently considered most likely to fall below the Active threshold at some point through day 3 (4th June).