Forecaster summary - Issued 2023-08-21T00:29:48

The high energy (greater than 2 MeV) electron flux remains close to Normal Background levels. A potentially strong recovery in flux at GEO is probable as the HSS from the newly determined CH/- in the western hemisphere wanes on Day 1 and 2 (21 and 22 August), and also given the current lack of any significant geomagnetic activity. Current guidance is for diurnal peaks to reach Moderate, possibly High levels. Confidence in the forecast reduces by Day 3 (23 August) with the forecast onset of a positive polarity CH that could reduce electron counts at GEO, continuing into Day 4 (24 August) should geomagnetic activity increase as anticipated. MOSWOC REFM modelling does not account for this in its forecast, which is already well above observed values and is likely to be too high on all days of the forecast period. Therefore the associated 24-hour fluence forecast will start below the Active (1e8 integrated pfu), but with a probable upward trend between Days 1-3 until increased geomagnetic activity later in the period allows electron fluence to reduce again, but with lower than average confidence.