Forecaster summary - Issued 2025-05-21T00:15:46

GOES-19 high energy electron flux has continued at mainly Moderate, briefly reaching High. Little change is anticipated through the period, although perhaps with peak values rising a little day 1-2 (21-22 May). A gradual and erratic reduction in peak values is then expected to follow. This is despite the ongoing fast wind, due to Earth lacking a strong connection given the positive polarity of this feature which is unfavoured at this time of year. Furthermore, any weak enhancements on day 4 (24 May), from either the further northward portion of the CH48/+ or the northern coronal hole CH50/+, could also help to drop these values out closer to background for a time.

The associated 24 hour electron fluence is forecast persist below Active (1e8 integrated pfu), perhaps rising a little for a time day 2-3 (22-23 May), but otherwise with a general declining trend. MOSWOC REFM is considered to still be over-estimating the likely fluence by T+48 and T+72, but providing better guidance at T+24.