Stormward

No agency publishes a list of active atmospheric rivers — there is a moisture field over the Pacific, and whether it counts as an AR is something you compute. Stormward evaluates the vapour-transport integral along the West Coast every hour from raw NOAA forecast data and ranks what it finds on the same scale meteorologists use, rather than waiting on someone else's advisory.

What it answers

• Rain before wind — the same 45 mph is a nuisance on day one and a pole failure on day three, because days of rain destroy root anchorage before the wind ever arrives. Wind-only models miss this.
• Where the plume lands — landfall position, duration and AR scale (Ralph et al. 2019) for the event in progress.
• What a burn scar does to the rain — a slope with no roots left by wildfire turns rainfall into a debris flow that takes out transmission structures and the roads used to reach them. This is where the wildfire board and this one become one system.
• Which territories sit under it — service areas intersected with the exposure footprint, with antecedent saturation already priced in.

Built on real data

Pressure-level temperature, humidity and wind come from NOAA's GFS model via Open-Meteo, evaluated 1000–300 hPa at eleven West Coast points with three days of hindcast so antecedent rainfall is measured, not assumed. Flood status comes from NOAA's National Water Prediction Service gauge network, hazard windows from National Weather Service alerts, and grid assets from HIFLD.