PDS-based Precipitation Chart Simplifier

This extension was developed to change data presented by the National Weather Service website into a format that is more easily copied into HEC-HMC and hydrologic spreadsheets. More specifically, it alters the DOM data of the PDS-based precipitation frequency estimates chart at https://hdsc.nws.noaa.gov/ from the average and range used to calculate the average to just the average.

The extension works by clicking the raindrop in the extensions toolbar. If the active tab is https://hdsc.nws.noaa.gov/ and there is a PDS-based Precipitation Chart loaded below the map, clicking the raindrop will inject a new chart below the current chart with only the average. The new-table auto-updates when you click a new location. Clicking the raindrop while the chart is injected into the page will cause the chart to be removed and normal functionality to resume.