Forecaster summary - Issued 2025-07-23T00:36:33

With the arrival of CH66/- on 22 Jul the Van Allen belt has been compressed away from the location of GEO, the GOES19 Electron flux then preceded to drop below the Active threshold after being persistently High since 19 July. This process may also be further enhanced on day 1 (23 Jul) by the inclusion of any glancing CME, although this final aspect is low confidence. Further charging is likely from this fast wind connection however, with some recovery likely later in the UTC working week (24-25 July), with High flux probable again as diurnal maxima.

The associated 24-hour fluence is currently above the Active level, but has likely seen its peak at 6.68e8 integrated pfu on 22 July, with a very slow decline now likely. Any drop-out could bring fluence levels below Active for a time later day 1 and day 2 (23-24 July), however these are likely to recover by day 3 with fluence rising above active likely by the end of the period. However this is low confidence by this stage. REFM is currently suggesting a steep drop below the active threshold, with no rise later, but continues to under-estimate likely fluence values.