How to use Agweather's drift risk advisor

              Drift Risk Advisor
Spray applicators are faced with the challenge of avoiding spray drift. Spray drift is defined as “the output from an agricultural crop sprayer
that is deflected out of the target area,” typically caused by wind. Spray drift can be hazardous to sensitive plants and animals.
To aid applicators in identifying times of higher drift risk due to weather variables, the Oklahoma Mesonet has created a Drift Risk Advisor.
This planning tool compares weather variable parameters with an 84-hour forecast matched to each Mesonet site. The Drift Risk Advisor
uses the National Weather Service 84-hour North American Model forecast. In addition to weather variables the Drift Risk Advisor has
forecasted dispersion conditions.
The Drift Risk Advisor is a weather-based planning tool that provides drift risk guidance, it does not supersede conditions at the field
at the time of application that may be different from the forecast. The final
judgement of whether conditions are appropriate for a spray application are
the responsibility of the applicator.
How to Use Agweather’s
article revised November 2009
Introduction:
Drift Risk Advisor Weather Variables:
Select “Upper” and “Lower Limits” that are appropriate for the application
material. Upper and/or Lower Limits can be entered for one, all or any
combination of the Drift Risk weather variables.
• Air temperature (Fahrenheit)
• Relative humidity (percent)
• Average wind speed (miles per hour)
• One hour rainfall (inches per hour)
• Wind direction
• Dispersion conditions
Dispersion conditions are based on the Oklahoma Mesonet Dispersion Advisor.
Dispersion conditions are reported as one of six levels of vapor dispersion.
These six categories are given text and number designations: Very Poor (1),
Poor (2), Moderately Poor (3), Moderately Good (4), Good (5) and Excellent
(6).
The Oklahoma Mesonet Drift Risk Advisor is located on the Agweather Web
site (http://agweather.mesonet.org).
Finding the Drift Risk Advisor:
- From the main Agweather page, select “Forecast”
- Choose “Drift Risk Advisor”
or
- From the main Agweather page, select “Crop”
- Choose any crop
	 - Under Pest Control, select “Drift Risk Advisor”
or
- From the main Agweather page, select “Horticulture”
- Choose any horticulture crop
	 - Under Pest Control, select “Drift Risk Advisor”