Forecaster summary - Issued 2021-07-24T00:01:13

High energy electron flux (greater than 2MeV) is expected to vary between Normal Background and Moderate levels over the next four days, in a similar pattern to the past working week. The recent weak high speed stream has persisted long enough to show that is not capable of causing any significant rise in electron populations in the near-Earth environment.

There is a chance of more sustained Moderate flux levels into the UTC weekend should the 20th July CME materialise. However, this aspect is low confidence, and current flux levels may persist throughout. 

Electron fluence values are therefore expected to remain well below the Active (1e8 integrated pfu) threshold. The Met Office REFM  model does usefully demonstrate this, in the absence of any CMEs. If the CME does materialise then an increase in the fluence is likely, but still not reaching the Active threshold.