Forecaster summary - Issued 2023-04-04T00:20:16

The high energy electron flux at GOES16 is at Moderate to High levels to start the period. There is a slight chance that weak CME influences later on Day 1 (04 Apr) could suppress observed flux values temporarily back towards Normal Background, adding slight uncertainty into the forecast.  

As the HSS from CH89/- and/or CH90/- affects Earth, either from later Day 1 (04 Apr) or on Day 2 (05 Apr), it is likely that some compression of the electron belts will take place and electron flux values return towards Normal Background levels for a period of time. Electron counts would be expected to rise again later on Day 3 (06 Apr) into Day 4 (07 Apr) as geomagnetic activity subsides, bringing an increased chance of High electron flux levels being reached again. 

Fluence levels start the period just above the Active threshold. Activity may fall back below this threshold for a time on Day 1 but rise again in-line with the diurnal electron cycle. Following the expected increased geomagnetic activity associated with the onset of one or more coronal hole HSS on Day 1 and/or Day 2, fluence should more persistently drop below the Active threshold, but may reach Active levels once again on Day 4 as Geomagnetic activity subsides and electron counts rise.  

MOSWOC REFM output is currently under-forecasting fluence levels, appearing to be lagged from the forecast values by around 24-hours. Applying an approximate 24-hour lagged trend to forecast data would seem to be a reasonable assumption for the current forecast. Recurrence has persistently over-forecast electron fluence in recent days and values are considered to high relative to expected values.