Forecaster summary - Issued 2023-12-21T13:29:42

High energy electron flux (greater than 2MeV) is at background to moderate levels on a steadily increasing trend on diurnal peaks. Peaks at high levels are possible on 21 and 22 December due to the recent but declining high speed stream. Further increases are subject to the possible connection to the next coronal hole high speed stream. However should this occur the onset could generate increased geomagnetic activity which may lead to a short suppression in flux levels. There is also a chance that much of the high speed stream may not connect with the Earth. Overall electron flux levels are forecast to be close to or slightly above the high threshold through the next four days.

Electron fluence values are showing a rising trend which is likely to slow with the shallower increases in electron flux forecast over the next four days. There is therefore a slight chance of reaching the Active threshold through the next four days, based on both the slower rate of increase in the flux and the uncertainty in the connection to the coronal hole high speed stream.