Forecaster summary - Issued 2021-04-16T00:09:05

The high energy electron flux (greater than 2 MeV) is expected to be at predominantly background levels at first, but likely rising during day 2 (17th), with temporary peaks above the Alert level (1000 pfu) at the diurnal maxima during Days 3 and 4 (18th and 19th). The corresponding 24-hour fluence is expected to remain below the Active threshold (greater than 1e8 integrated pfu) throughout the period, but with an increasing trend.

A very gradual increasing trend is indicated by the 3-day REFM forecast, which is considered slightly underdone for the rate of increase, but overall good guidance. The 27-day recurrence is not giving good guidance because of a different solar wind regime on the previous rotation.

The recurrence-persistence model has values rising by the end of the period (28 percent by Day 4), which is considered reasonable.