EsriThe National Water Model provides forecasts of flow volume and velocity for over 2.7 million stream and river segments in the contiguous United States and is the National Weather Service's primary tool for predicting river flooding. Two versions of the National Water Model are available in ArcGIS Living Atlas: a short-term model that updates every hour for 18-hrs, and a medium-range model that updates every 6-hrs for a 10-day outlook. This layer provides a summary of the short-term hourly forecast and adds calculated fields such as flow anomaly, maximum anomaly, and the time at maximum flow. It has been filtered to display only areas with positive flow anomalies (i.e., flooding). Leveraging ArcGIS Online hosted feature services, it is ideal for doing spatial and time queries, use in Dashboards, and supporting a variety of custom symbology. By default, this layer is showing time until maximum flow since the short-term model is ideal for providing detailed situational awareness for imminent or occurring events. Companion Layer National Water Model Maximum Flow (10-Day Forecast) Related Layers National Water Model (10-Day Forecast) National Water Model (10-Day Anomaly Forecast) National Water Model (Hourly Forecast) National Water Model (Hourly Anomaly Forecast) Revisions Jan 27, 2022 : Added 'Forecast Origin' field. Providing the Origin Date/Time of the Forecast SetArcGIS FeatureLayerhttps://hub.arcgis.com/datasets/28dbd58ad90e4a47ab0e0334d2b69427_0engIsanti County Geospatial HubPublicNational Water Model Maximum Flow (Hourly Forecast) [Minnesota--Isanti County]Web servicesMinnesota--Isanti CountyMinnesotaLast Modified: 2026-01-08