Example 1 of 4

Time series
Base series (μ=0) Shifted series (μ) Above threshold Newly crossed (this step)
Left: the whole time series shifts upward by μ while the threshold stays fixed.
MHW days (count)
Other MHW metrics
MHW events (contiguous)
Mean duration (days/event)
Avg peak intensity (°C above threshold)
Right: the curves emerge during the animation. The dashed “early trend” line appears at the end (examples 2–4) so the upward bend is obvious.