Forecaster summary - Issued 2019-11-21T00:30:43

The high energy electron flux will remain below high levels at first on day 1, before increasing during the day, to reach the high threshold either late on 21 Nov or during 22 Nov. On the previous rotation there was a lag of 24 hours between the onset of the strong winds and the increase in high energy electron flux values above the high (1e3 pfu) threshold. A slightly quicker response is likely on this rotation as the flux values are already elevated in comparison to 27 days ago.  Therefore the high threshold is likely to reach the high threshold some point on 21 Nov and remain above this through the next three days.

Corresponding fluence values are also slightly elevated against those in the equivalent point last month. Based on 27-day persistence an increase above the Active threshold (1e8 integrated pfu) would be expected on day 1 (21 Nov). However the increase in fluence on this rotation is not expected until day 2, due to a slightly slower onset this time, although the REFM model has not yet forecast this increase. The chance of the Very Active (1e9 integrated pfu) level being breached is considered less likely than the previous rotation because of a smaller coronal hole and slower solar wind speeds.