Forecaster summary - Issued 2018-12-09T00:19:04

The high energy electron flux (greater than 2 Mev) is currently at background levels. However, with a high speed stream now established at Earth, electron counts are expected to continue steadily increasing, although some temporary redistribution is likely associated with any increased geomagnetic activity, especially on Day 1 (9 Dec), but this is considered a slight chance (10%). There is an increasing likelihood of peak flux levels reaching or exceeding the high threshold (1000 pfu) on the diurnal maximum through the forecast period.

The corresponding high energy (>2MeV) electron fluence is also expected to show a rising trend through the period. There is an increasing chance that the corresponding 24-hour electron fluence will reach the Active threshold (greater than 1e8 integrated pfu) by Day 3 (11 Dec). During the previous rotation this is the level that fluence approached by this time. Note that probabilities have been raised significantly compared to previous forecast.