Forecaster summary - Issued 2025-07-02T00:12:34

GOES-19 High energy (greater than 2 MeV) electron flux levels have reached diurnal High thresholds following the weakening of the HSS originating from CH59/– and subsequent decline in geomagnetic activity. As solar wind pressure subsided, this allowed the belts to expand outward toward geosynchronous orbit (GEO), resulting in elevated electron flux levels. However, CME arrivals and another HSS connection are forecast for Days 1 and 2 (02-03 Jul), with geomagnetic activity expected to increase. This will have the effect of suppressing the electron belts back below GEO, reducing the observed electron flux. By Days 3 and 4 (04-05 Jul), geomagnetic activity is expected to decline, and the electron belts will be allowed to expand back out towards GEO once again. 

MOSWOC REFM isn't currently providing a useful steer for the electron fluence forecast, likely due to lingering CME contamination from the previous solar rotation. Fluence is expected to remain at or just above the Active threshold, at least through the start of Day 1 (02 Jul). With electron flux expected to fall (as mentioned above), fluence is also expected to fall, likely dropping below the Active threshold level. A rise in fluence towards the end of the period is possible as electron flux levels start to rise again following the easing of CH and HSS influences. This all assumes that the forecast CME and HSS materialise.