Forecaster summary - Issued 2021-04-22T00:13:46

The high energy electron flux (greater than 2 MeV) as observed by GOES-16 is currently High, even at the diurnal minimum, and expected to stay that way through to the start of Day 2 (23 Apr). The arrival of the fast wind of CH47/- may lead to a more significant drop out in flux during Day 2, before a recovery to mainly High levels occurs through Day 3 (24 Apr) and Day 4 (25 Apr). Although confidence in this particular aspect is low, due to uncertainty both over the likely wind speed and the geomagnetic effects. 

The associated fluence is currently Active, and expected to persist at these levels through Days 1 and 2. This is supported by REFM, which is giving good guidance. There is a slight chance of fluence levels reaching Very Active levels on Days 1 and 2. There is potential for a decrease on Day 3, but confidence is low in this aspect. Even if this does occur, a recovery to Active levels is likely towards the end of the period.