Ohio Applicator Forecast
The Ohio Applicator Forecast is designed to help nutrient applicators identify times when the weather-risk for applying is low. The risk forecast is created by the National Weather Service and takes precipitation, temperature, and snowmelt data to estimate the amount of water in each area. This amount of water is used with soil data, such as texture and depth, to determine how much should soak into the ground, and how much should flow over the surface.
- When the map is clear and shows No Runoff Expected, either no precipitation or snowmelt is expected within 24 hours, or the soil is so dry that any water present is expected to soak in.
- When the risk is Low, some precipitation or soil moisture may occur, but a runoff event is unlikely.
- Moderate and Severe risks appear when precipitation or snowmelt is likely, or when soil moisture is high enough that water may flow through or above the ground.
- Also, during winter areas where the ground is expected to be frozen or snow-covered will appear as blue, and when these conditions are combined with some level of risk, the area will appear as purple.
The 3-day forecast of surface runoff risk are displayed on the overview maps of the state. If you zoom to street level, seven days of weather conditions and runoff chances are predicted.
Using the Ohio Applicator Forecast
The forecast map divides the state into approximately 48,000 square grids, each covering an area of 4 sq. km (988 acres). The overview map shows the daily runoff risk for the next 3-days. Each grid has a seven-day runoff risk and weather forecast, including precipitation, air temperature and soil saturation and temperature. The forecasts are updated twice daily, around 4:00 AM and 7:00 AM.
To view the risk and weather forecast, open the Forecast Map, zoom in to your area and click on one of the grid squares to open a popup window.
Risk is grouped into 4 categories: None, Low, Moderate, and Severe. When the risk is Moderate, it is recommended that the applicator evaluate the situation to determine if there are other locations or later dates when the application could take place.
The runoff forecast map is a decision-support tool, not a regulatory tool. When making your decisions, please consider the following:
- The model is not predicting if nutrients will actually runoff after you spread from your field, it is predicting the potential for any runoff to occur in your area within the next seven days.
- Field specific conditions should still be evaluated
- Runoff risk increases with soil moisture
- Spreading liquid manure increases soil moisture
- The model assumes equal wetness across the grid area, if your field is more or less wet, then your risk will be respectively higher or lower
- Runoff risk increases with snow cover
- The model assumes the entire grid area has snow cover; if your field has more or less snow cover, then your risk will be respectively higher or lower
- High Risk fields have higher slopes, compact soils, poor drainage or are close to sensitive features (streams, lakes, wetlands, sinkholes, etc.)
About the Forecast
The runoff forecast is derived from real-time precipitation and temperature forecasts. These data are combined with snow melt, soil moisture and temperature predictions to forecast runoff events. These prediction models were tested and validated using data from USGS gauge stations, and from OSU and USDA ARS field experiments.
The "Find Location" button on the map uses HTML Geolocation to find your approximate location. When run on mobile devices, by default it uses GPS on the device to locate the place. When run on desktops, it uses network signals to estimate the location. This method is usually less accurate than for GPS-enabled devices. Users might get an error message after clicking the 'Find my location' button. It is often caused by the browser's security. Check the browser's setting for pop-ups asking if you want to share your location. Click Yes to find your location.
Frequently Asked Questions
The runoff risk forecast takes precipitation, temperature, and snowmelt data to estimate the amount of water in each area. This amount of water is used with soil data, such as texture and depth, to determine how much should soak into the ground, and how much should flow over the surface.
When the map is clear and shows No Runoff Expected, either no precipitation or snowmelt is expected within 24 hours, or the soil is so dry that any water present is expected to soak in.
When the risk is Low, some precipitation or soil moisture may occur, but a runoff event is unlikely.
When interpreting the forecast, keep in mind that it is not predicting if nutrients are actually going to runoff from your specific field. Rather, it is predicting the potential for any runoff to occur anywhere in the area, should spreading occur.
When the runoff risk is moderate, it is recommended that you closely evaluate the field-specific conditions to see if spreading is appropriate. Lower risk fields should be identified, such as flatter, drier sites away from surface water and areas of concentrated flow.
It is recommended that you avoid spreading nutrients when the runoff risk is high.
If fertilizer or manure can be injected or immediately incorporated, the soil is not considered frozen.
Application on frozen and snow covered soil is not acceptable. Dry manure can be stockpiled using the procedures established in the Ohio NRCS practice standard code 634.
In an emergency, if manure application becomes necessary on saturated, frozen, or snow covered soils, only limited quantities of manure shall be applied and in accordance with procedures established in the Ohio NRCS practice standard code 590. In the Western Lake Erie Basin, written consent must be obtained by the ODA Division of Soil & Water Conservation before spreading manure under restricted conditions.