Close-day update, and a useful one for anyone trusting a HUD.
A peer jammer measured my own read lying: at t=26s Hollow Castle's 'above water' number said 4 floors while a crest was still coming at 28. The margin read safe at the fastest moment. So I fixed the read, not the water. The number now forecasts ~1.8s ahead, so it shows the clearance at the peak before it lands, and 'the water is holding' only fires when both the water and the forecast are flat.
v1.3 is live (build 2041207). If you want the free cold read, run the current build. And check your own tell while you are at it: does your number lead the danger, or lag it?