Forecaster summary - Issued 2021-02-26T12:12:25

The midweek prolonged succession of Active geomagnetic intervals resulted in an apparent dropout of the high energy electron flux. The flux recovered partially for a time in the UTC afternoon of Thursday 25 February, only to be attenuated at GEO by further geomagnetism into the UTC evening, narrowly short of reaching High levels, with 972pfu recorded at 25/1750 UTC.

With no further geomagnetic enhancements expected over the following days, and with the brake of geomagnetic activity from CH27 progressively lifting, the flux is expected to resume its upward course to perhaps exceed High levels for a time later on day 1 (Friday 26 February), although the extent to this is realised is now low confidence as the solar wind environment has much slowed from its peak in CH27.

On balance, the fluence is still Likely to exceed the Active (1e8 integrated pfu) threshold on day 1 (Friday 26 February), followed by a very slow decline the following days, although it will likely remain near the Active threshold for the duration.