Forecaster summary - Issued 2024-05-22T11:28:11

High energy flux, as observed by GOES-16, has continued on a slow upward trend as the solar wind environment eased, with an increasing chance of reaching High flux at periods of diurnal maximum. This trend is expected to continue until day four (25 May), when the arrival of any fast wind from southern extension of the northern coronal hole CH39/+ is likely to subdued the observed values at GEO. 

While a slow upward trend is expected to the associated 24 hour fluence, this is now expected to remain below the Active threshold, likely peaking on day 3 (24 May), before declining again as a consequence of any HSS onset. This upward trend is indicated by MOSWOC REFM through day 1 (22 May), but then likely decreases the observed flux too quickly beyond T+24. However, this does support below Active fluence persisting.