Turning Raw Weather Into a Drying Model

In the first article about my foray into using weather data to assess surface conditions for riding activities, I introduced the Groundwise engine, a software decision system that turns weather data into a yes/maybe/no verdict for outdoor conditions. This article goes deeper into the core moisture model: how the engine takes raw weather observations and calculates a wetness score that drives the verdict. The hope is to show how a simple question such as "can I ride my mountain bike today?" spiraled into a fairly complex yet intriguing design challenge. Totally fair if you aren't entranced by weather math, I get it, but I feel like there's some value in pulling back the curtain to reveal how much goes into solving a seemingly simple problem. The Groundwise model is relatively restrainted in scope, it isn't trying to simulate soil physics. It's trying to approximate what an experienced local would know instinctively — "it rained pretty hard yesterday, but it's been warm and windy all mor