National Water Model Maximum Flow (10 Day Forecast)

The 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 10-day 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 the maximum expected flow for each river segment since the 10-day model is ideal for providing a more synoptic understanding of potential flooding. Companion Layer National Water Model Maximum Flow (Hourly 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 Set国家水文模型（National Water Model）可为美国本土超过270万个溪流与河段提供流量与流速预报，是美国国家气象局（National Weather Service）预测河流洪涝的核心业务工具。 ArcGIS 生活地图集（ArcGIS Living Atlas）中提供了两款国家水文模型：一款为短期预报模型，每小时更新一次，预报时效为18小时；另一款为中期预报模型，每6小时更新一次，可提供10天的预报展望。 本图层汇总了10天期预报结果，并新增了流量异常（flow anomaly）、最大异常值以及流量峰值时刻等计算字段。该图层已通过筛选，仅展示流量异常值为正的区域（即发生洪涝的区域）。 本图层依托ArcGIS Online（ArcGIS Online）托管要素服务，可完美适配时空查询、仪表板（Dashboards）集成以及各类自定义符号系统配置需求。 默认情况下，该图层会展示每个河段的预估最大流量，因10天期模型更适合用于宏观概览潜在的洪涝风险。 配套图层：国家水文模型（小时预报）最大流量。 相关图层包括：国家水文模型（10天预报）、国家水文模型（10天异常预报）、国家水文模型（小时预报）、国家水文模型（小时异常预报）。 修订记录：2022年1月27日：新增“预报来源（Forecast Origin）”字段，用于提供预报集的来源日期与时间。