SITE TABLE OF CONTENTS
National Weather Service Flood Forecasts
All Forecasted River Conditions in the Red River Basin are prepared by the North Central River Forecast Center (NCRFC). The NCRFC is located in Chanhassen, MN.
There are two types of forecasts that are prepared, a deterministic and a probabilistic.
Deterministic forecasts provide a forecast of specific flood levels and the specific time that they will occur. These deterministic forecasts are issued as needed during times of high water, and are not routinely available. These forecasts typically provide a forecasted flood level out seven days into the future. The National Weather Service has prepared a short video describing in detail how to interpret these forecasts.
As an example, the deterministic forecast at the Fargo gage on the Red River of the North will be located here when a forecast is issued.
The NWS uses forecast models to estimate the quantity and timing of water flowing through selected stream reaches in the United States. These forecast models (1) estimate the amount of runoff generated by precipitation and snowmelt, (2) simulate the movement of floodwater as it proceeds downstream, and (3) predict the flow and stage (water-surface elevation) for the stream at a given location (AHPS forecast point) throughout the forecast period (every 6 hours and 3 to 5 days out in many locations). For more information on AHPS forecasts, please see.
Probabilistic Forecasts are a longer-term outlook on flooding based on what is called the Ensemble Streamflow Prediction or ESP. The NWS River Forecast model takes the present conditions and applies the weather conditions from a specific historical year for a 90-day period of interest to the model. This process is repeated for many years of historical data to generate a flood peak forecast along with the probability that a given flood peak will occur. A detailed explanation of the process is located here.
There are two parts of the probabilistic forecast issued by the NCRFC in graphical form. One is the Weekly Chance of Exceeding Levels and the other is the Chance of Exceeding Levels during the Entire period.
The Weekly Chance of Exceeding Levels graph gives the user an idea of both the magnitude and timing of the flood. As an example, the graph for the Fargo gage on the Red River of the North is located here. More details about this graph can be found here.
The Chance of Exceeding Levels During Entire Period graph gives the user an idea of the magnitude of flood that may occur over the course of the forecast period. As an example, the graph for the Fargo gage on the Red River of the North is located here. More details about this graph can be found here.