A burn plan has constraints on the weather, such as minimum and maximum winds. This is often called the prescription. You have to check the weather forecast for the next few days to see if the weather will be within those constraints.
Apart from the weather, there are additional constraints, such as: how early you can burn after sunrise; how late you can burn before sunset; and how many hours you need for your prescribed burn. The Check Burn Weather page can help you find days that meet all these constraints.
There are two types of constraints: essential and preferred constraints. Any essential constraint (black) for which a value is specified must be met. Preferred constraints (blue text) are used to judge the quality of a burn period.
Location: The latitude and longitude of your location. They are used to get the NOAA weather forecast for your location.
Slope: TRUE if the slope is greater than 30%.
(Inputs for slope, aspect, shaded and area are used to calculate the fine fuel moisture and PIG)
Slope aspect: Compass direction of the slope going down.
Shaded: TRUE if the area is shaded by more than 50% by the canopy.
Area > 1000': 'Above' if the burn area is > 1000 feet higher than the height for which the weather forecast is made, 'Below' if > 1000' lower, 'Level' otherwise.
Wind Speed: The wind speed is measured at 30 feet. You should only burn when the wind speed is expected to be between 6 and 23 mph.
20 Foot Wind Speed: The wind speed expected at 20 feet.
Wind Gust: The maximum wind speed that is expected in an hour interval. It is measured at 30 feet.
Probable rain: This set a limit on the amount of rain in an hour interval. It is the product of the predicted amount of rain and the probability of that rain. (A medium rain rain with a very low probability results in a low 'probable rain.)
Mixing Height, Transport Wind, Ventilation Rate and Category Day Index: These parameters all have to do with smoke management. Instead of specifying fixed limits for mixing height and for transport wind speed, you may set a limit on the ventilation rate (which is the product of mixing height and transport windspeed.) Or you can simply specify a Category Day Index. This index describes different ranges of ventilation rate. Texas regulations require an index of 3 or higher for prescribed burns, so you can input a value of 3 or 4 and leave the preceding three inputs blank.
Wind Direction and Transport Wind Direction: By default all wind directions are allowed, but you can uncheck the ones you don't allow.
Dead Fuel Moistures: The location is used to get information about the current dead fuel moistures. The weather forecast is used to predict how these moistures will change over time. Rain will raise the moisture.
WARNING: I can no longer find a local measurement of dead fule moisture, so the initial value is a guess.
Burn Duration: Use this to specify how many hours you expect to need for your burn.
Certified Prescribed Burn Manager: When you have a CIPBM at your burn you can check this box. It may allow you to start an hour earlier or allow you to burn during a burn ban.
Ignore Burn Ban: If you do not have a CIPBM and there is a burn ban, you cannot burn. Select this option if you are curious what days would have been available without the burn ban.
When you have set your constraints for a burn, you can also indicate your preferences. If a burn period meets the preferred limits, it will show a higher quality in the Period Quality plot.
The Save Inputs button saves the current values of the input parameters; the Load Inputs button set the input values to those that were last saved.
Click the Submit button.
Disclaimer: The accuracy of any result is limited by the correctness of the weather forecast; the fire behavior models; and by my implementation.
The yellow Status window shows the status of the execution. When the execution is Done, it shows those periods that meet all your essential criteria.
The Results window shows a number of plots. For example:
The Excluded Hours plot shows the reasons why a specific hour is not allowed. For example: it may be night or too soon after sunrise; the wind may be to weak or too strong; the wind may come from a wrong direction; or the ventilation rate is too low.
The Allowed Burn Periods list hours that you can burn. It checks the hours are long enough to cover the specified Burn Duration.
The Period Quality show positive and negative aspects of the hours during and after an allowed burn period.
The Dead Fuel Moisture is shown assuming that there is no rain at all. This shows the minimum possible moisture in fine fuel, grass and 10, 100, and 1000-hour fuels.
Fine fuel moisture refers to the water content in small, dead plant materials like leaves and twigs .
Dead Fuel Moistures are also shown for the maximum predicted rain.
Grass Rate Of Spread (ROS) & PIG shows the ROS for standing tall cured grass, assuming that there is no rain; as well as the Probability of Ignition for fine fuels in %.
The Wind Direction shows the direction of the surface wind and the transport wind. Zero degrees and 360 degrees is North. When the wind directions shifts through the North direction, the plot jumps between 0 and 360.
The Rain plot shows predicted rain and the probability of precipitation. Probable Rain is the product.
The Ventilation Rate shows both the predicted ventilation rate and the corresponding Category Day Index.
After an execution, you can try another set of constraints and hit submit again.
The execution gathers information from multiple servers, some of which may time out. When that happens, you could try to Submit again. If that does not help, reload the page. And if that doesn't help, email Jheroen.