Forecaster summary - Issued 2025-12-21T13:13:43

Electron flux is expected to be at Moderate levels now the fast winds of CH09/+ have arrived and continue to compress the Van Allen belts away from GEO.  There remains a chance they may reach diurnally High. This HSS is expected to continue or much of the period, with a chance of waning through day 4 (24 Dec). With the lack of any Earth-directed CMEs to reduce electrons, electron flux may begin to respond mid fast winds with the likely charging of the Van Allen belts, with diurnal high becoming increasingly likely through the period.

Electron fluence is expected to be at Active levels through the second half of day 1 (21 Dec) before declining below Active either by the end of the day or perhaps by early day 2 (22 Dec). However, with the recent Active period, followed by the current charging via the HSS of CH09/+, fluence levels may one again rise later day 3 or day 4 (23-24 Dec), with a slight Chance of Very High (<1e9 pfu).  MOSWOC REFM is currently providing good guidance for fluence levels late day 1 into day 2 (21-22 Dec), perhaps with a similar trend toward recurrence expected later in the period.