Forecaster summary - Issued 2020-11-21T00:00:19

The high energy electron flux (greater than 2 MeV) is expected to remain at mainly background levels, but is likely to increase during days 2-4 (22nd-24th) to above the 1000 pfu threshold at the diurnal max. The associated 24-hour fluence is forecast to remain below the Active (1e8 integrated pfu) threshold, but is likely to rise later in the period, with the fluence possibly exceeding the Active threshold on Day 3 (23rd). This is broadly supported by the REFM 3-day forecast, which indicates ongoing low values, but with a slight rising trend. The 27-day recurrence suggests a breach above the Active threshold by then end of Day 1 (21st), but this is considered too quick, and a 24-48 hour delay is likely based upon the strength of coronal hole 96. The recurrence-persistence model has percentages rising to near 30 percent by Day 3, which is considered more realistic on this occasion.