This may fit better in an existing Milestone.

User story: As a water resource manager, I need quick access to sites that are experiencing drought conditions in order to determine how much water to keep in the dam for late summer agriculture needs.

Feature: Enable filtering of a national map of sites with current conditions in drought status relative to historic averages. Also enable mapping by HUC2 (maybe finer scale HUCs, depending on user needs) and by different time windows.