Unit 8: Keeping Current with The Weather

Forecasting  ::  AFFIRMS  ::  Warnings  ::  Management  ::  Services  ::  Mobile Units  ::  Forecasts  ::  Monitoring  ::  Exercises

Objectives:

Upon completion of this unit you will be expected to:

• Describe and give the purposes for each of these forecasts available to fire managers - general fire weather, red flag warning, special spot weather, smoke management, and fire behavior forecasts.
• Describe AFFIRMS and the services it provides to resource management agencies.
• Describe four steps essential to getting a good spot weather forecast.
• Discuss weather monitoring and observations that should be made on fires and their locations and frequency.
• Describe the purpose of a security weather watch and how it is established.
• Give six benefits of having a mobile weather unit on a fire.
• Give four weather measurements that can be taken with the belt weather kit, and the standards for accuracy for each.

Introduction:

Because fire behavior processes are so dependent on elements of weather, this course puts strong emphasis on weather and its changeability. Fire managers recognize this fact and have grown very dependent on weather forecasts and other means of keeping current with the elements of weather and fire danger. Fire management organizations have special needs for weather forecasting services.

Daily Forecasting Services

Fire management needs for weather forecasting services are:

1. Planning daily fire management activities.
2. Planning effective control actions on fires.
3. Determining potential hazards due to fires.

Types of Forecasts

Fire weather offices (NWS) provide forecasting services to resource management agencies. Usual types of forecasts are:

1. General fire weather forecast.
2. Red flag warning.
3. Smoke management forecast.
4. Spot weather forecast.
5. Mobile weather unit forecast.

Regular forecasts issued by fire weather offices are:

1. General fire weather: Planning of daily fire management activities including daily manning levels, prevention programs, and initial attack on wildfires.
2. Red flag warning: Alert fire managers of critical or rapidly changing fire weather conditions that will increase fire danger in a significant way.
3. Smoke management: Advises fire managers of atmospheric conditions for the next 36 hours that will affect the dispersal of pollutants from fire.

Zone forecasts make up the bulk of the general forecast. Each state of any size is divided into several weather zones. A zone encompasses an area that normally has similar weather characteristics. Each of the numbered weather zones has at least one fire weather station that provides the forecaster weather observations each day. Notice that the predicted temperature, relative humidity, and wind are not given here, but are rather the expected changes over today's readings. These change values are applied to today's local fire weather observations to give tomorrow's predicted weather elements.

Why is this format used in the forecast you may ask? Well, one of the principal purposes of this forecast is to provide input into the National Fire Danger Rating System. The zone forecast elements as shown are also put into a computer, which processes the data and calculates fire danger indices and components. We'll discuss this data processing and fire weather information system a little later

Zone Forecasts

Zone Weather Forecast: A portion of the general fire weather forecast issued on a regular basis during the normal fire season specifically to fit the requirements of fire management (time, areas, and weather elements). These zones or areas are a combination of administrative and climatological areas, usually nearly the size of an individual forest or district.

We should discuss the zone weather forecast a bit more. The zone weather forecast is issued on a regular basis during the normal fire season specifically to fit the requirements of fire management needs such as time, areas, and weather elements. The forecast zones or areas are determined based on a combination of administrative and climatological information, and usually are nearly the size of an individual forest or district. They are numbered for convenience in reference. The zone forecasts are coded. The principal weather elements are state of the weather, temperature, relative humidity, wind, precipitation duration, lightning activity level, and fuel moisture.