Forecaster summary - Issued 2021-05-16T00:14:21

High energy electrons (greater than 2MeV) should remain in their current oscillating pattern mostly within Normal Background levels at first. The onset of the high speed stream from CH57/- late on day one or perhaps into day two may eventually bring to bear on 24-hour integrated fluence, although this is low confidence given the presence of up to two transients (13 and 14 May CMEs) over a similar period. Geomagnetic activity as a whole is likely to be prolonged by the arrival of CH59/- at the end of the forecast period, meaning that an expected rise in fluence is likely to appear hesitant, but perhaps increasing to a Chance by the end of the period.