Forecaster summary - Issued 2025-07-20T00:10:09

GOES-19 high-energy (>2 MeV) electron flux has mostly remained at High levels over the past 36 hours, peaking at 11,600 pfu at 19/1715 UTC. These high flux levels are expected to persist, perhaps with temporary diurnal returns to moderate levels, under the waning influence of the high-speed solar wind stream associated with coronal hole CH63/+. A more sustained decrease is anticipated following the arrival of a high-speed stream from coronal hole CH66/-, though this is not expected until Day 4 (23 Jul).

The Electron Fluence is currently above the Active threshold (1e8 integrated flux), and is expected to remain so throughout the period. Due to the lack of geomagnetic activity, and ongoing HSS, there is a slight chance that the fluence may achieve Very High levels (1e9 integrated flux). The overall trend above Active levels, as shown in the MOSWOC REFM, is considered to provide reasonable guidance to start, though it is likely underestimated. A slight decrease is possible by Day 4, although the onset of the next HSS is likely to be too late in the forecast period to see any significant decrease in fluence, with the drop indicated in REFM deemed too early.