Forecaster summary - Issued 2021-03-09T00:01:32

The high energy electron flux (greater than 2MeV) is likely to rise above the 1000 pfu Alert level at diurnal maxima over the next few days, due to the current coronal hole high speed stream. The corresponding 24-hour fluence is currently below the Active (1e8 integrated pfu) threshold, but is showing a rising trend. This may lead to a period of Active fluence values during Days 1-3 (9-11 March), though confidence is rather low with respect to the onset and potential strength of this. The REFM 3-day forecast model suggests a rise above the Active threshold by late on Day 1 (9 Mar). The 27-day recurrence isn't of much help at present, as the current coronal hole didn't really exist on the last rotation with wind speeds much lower. 

Then on Day 4 (12 Mar) we expect the arrival of another high speed stream, with some associated geomagnetic activity. As such it is likely that the onset of this new high speed stream may deform the van Allen radiation belts, showing as a decrease in electron levels at GEO, before a rebound in electron levels after the end of this forecast period. Confidence however is low at this stage, especially as to the starting values of the electron fluence at the onset of the high speed stream.