Forecaster summary - Issued 2025-05-27T00:11:24

Electron flux at GOES19 has been Moderate over the last 24 hours, following the fast speed stream from CH48/+. No further significant enhancement from this coronal hole is expected, with electron flux levels likely to remain similar initially. The next coronal holes likely to enhance electron flux are CH51/- and CH52/- from day 2 or 3 (28-29 May) onwards, with charging of the Van Allen belts as a result. Increased levels of electron flux may not be observed at GEO until the end of this forecast period as the belts relax back out, with diurnal Highs then possible.

The associated fluence is currently below the Active (1e8 integrated pfu) threshold and is displaying a generally flat trend. This is most likely to continue over the following days, with no or little chance of rising. This is supported by the latest MOSWOC REFM which suggests an overall declining trend and is considered to be good guidance, at least at first. A potential rise in fluence late in the period is possible following any connection to CH51/- and CH52/- increasing electron flux at GEO, which is hinted at by REFM.