Forecaster summary - Issued 2018-05-18T00:20:42

The high energy electron flux (greater than 2 MeV) at GEO was at high levels (above 1000 pfu) until 17/0200 UTC, after which time the flux dropped rapidly to background levels. The high energy electron flux then returned to high levels between 17/1310-2050 UTC. The corresponding 24-hour electron fluence started well above the high threshold (1e8 integrated pfu), but fell sharply in the evening, whilst still remained at high levels.

 The high energy electron flux (greater than 2MeV) at GEO is expected to be at moderate to high levels throughout. The corresponding 24-hour electron fluence may temporarily fall below the high threshold (1e8 integrated pfu) today, but is likely to remain above the high threshold for most of the forecast period.

The REFM forecast has current and past fluence levels too low, though is correct in predicting the latest values remaining above the high threshold, despite the sharp falling trend. Today the high energy electron fluence may temporarily fall below the high threshold, which the REFM model doesn't reflect. However, overall the model offers reasonable guidance in showing a rising trend in the fluence back above the high threshold, albeit too slow, with this happening in reality either late today or through tomorrow.