The last completed forecast period, replayed: the forecast as it stood when the period began, then the station's readings drawing over it hour by hour, the events as they fired, and the verdict at the end. Its twin, How it was made, replays the run that built the forecast. Nothing here is recomputed; it is the period as the record kept it.
The period is the low Tue Nov 10 night, 7 PM to 8 AM. The curve is the hour-by-hour forecast as published when the period began (the Hour by hour page's, which starts from the station's reading), or until the Tower has kept one, the curve frozen for the Today page's own grading; the sources in the verdict are graded as the Scoreboard grades them, on the forecast of record before the period began. The strip along the top is the sky as the station saw it: by day the sun it measured as a share of a clear sky, bright when clear and grey when overcast; by night, with no sun to read, the grass's gap under the air, blue when wide (a clear sky) and grey when narrow (cloud or wind). The dotted grey line is the dew point. The strip under the chart is the pressure (the line, in millibars) and the rain since the period began (the blue fill, in inches). The arrows along the bottom are the wind each hour, pointing where it blows, longer when stronger, with the speed in mph under each (and the gust after a slash when it is 5 mph or more above). The events follow the rules on How it's going. Every reading of the period is on the Readings page.