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River conditions change rapidly, and so does the weather that affects them. To predict the most accurate streamflow, HydroForecast leverages the latest weather data as inputs.
Yesterday's weather data, even if only a few hours old, is already less accurate than what's available right now. By frequently updating our forecasts when new weather data becomes available, we ensure that our hydrological models are always working with the most up-to-date weather. This means capturing subtle shifts in pressure systems, changes in precipitation patterns, and evolving temperature fronts—all critical inputs that directly impact water flow.
We pull the most recent weather information from a diverse array of global weather models—ECMWF, GFS, GEFS, and HRRR. The specific weather inputs will vary depending on region and availability. Each of these weather models provides unique insights. By combining them and prioritizing the most current data, we create a more robust and resilient forecast.
>> Learn more about our weather data inputs.
Weather forecasts are run by public meteorological agencies (either NOAA or ECMWF), and when they are publicly available, we use them as inputs into HydroForecast.
HydroForecast Short-Term releases two primary forecasts per day, every 12 hours. Between these two primary updates, the model checks for adjustments every two hours and ingests additional data to ensure that your forecast reflects the latest conditions.
During these checks, we incorporate:
GFS and HRRR both update more frequently than ECMWF and GEFS. Below is an example of the first time HydroForecast was issued that day, and the last time the forecast was updated. You’ll notice that the model incorporates the latest available GFS and HRRR as they are released!
To better understand how HydroForecast Short-term processes and updates data, the definitions below offer a closer look at key timestamps in the forecasting workflow.
The initialization time marks the beginning of the forecast period. Think of it as the moment a "snapshot" of the initial conditions is taken for the forecast to begin its calculations.
The issue time refers to when the completed forecast is actually published and becomes accessible. You'll notice a delay between these two timestamps, not because of inefficiency, but because it takes time for those critical, just-processed weather model outputs to become available.
It’s easy to see exactly which data was used in your forecast with the HydroForecast dashboard. For every forecast we issue, we share the initialization and availability times of the specific weather inputs used.
>> Read more from our Knowledge Base: When forecasts are issued and available.
HydroForecast provides a level of transparency and accuracy that gives users confidence in the results and empowers better decision-making. Having the most up-to-date and accurate forecast is essential for effective water management, resource allocation, and risk mitigation.
Contact our team to learn more and get started today.
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