Forecaster summary - Issued 2023-07-19T00:13:15

High energy electron flux (greater than 2MeV) has risen to moderate levels in the past 24 hours following the CME that arrived on the 16th, the associated magnetic cloud progressively charging the radiation belts. A further diurnal rise is expected to be relatively modest on day 1 but may exceed high levels during the diurnal peak. The denser and stronger winds associated with the CME expected to give Earth a blow on day 2 (20th) may reduce temporarily the electron flux but these should replenish the radiation belts by day 4 (22nd), leading the fluence to potentially breach the Active threshold (1e8 integrated pfu). Low confidence in the timing of this scenario though. The latest Met Office REFM output is in reasonable agreement although it is thought to under-estimate the impacts of the coming CME.