Forecaster summary - Issued 2024-04-22T00:21:29

High energy electron flux as observed by GOES16 rose from persistent Background to brief Moderate levels on 21 Apr, as a result of the recent CME arrival and CH HSS onset that had been observed on the previous days. As solar winds ease, any charging that has occurred at lower orbits is expected to become increasingly relevant at GEO, with the observed flux rising to Moderate and likely peaking at High for a brief period at diurnal maximum. This is only moderate confidence however, as the arrival of any CMEs may help to modulate the observed flux, and any more notable arrivals have the potential to drop values back towards background.

The associated 24 hour electron fluence is expected to continue on an upward trend, as indicated by REFM, which is giving a good guide in the absence of any CME arrivals, but perhaps under-estimating peak values a little. This will give a slight, but increasing chance of reaching the Active threshold by day 3 (24 Apr), although this potential will reduce should any dropout from any CME arrival occur.