How do I interpret the Heat Load Outlooks

The Heat Load Outlooks will take on a more formalised language this season. They will also align with the current alert thresholds based on AHLU and provide a description of the risk along with the weather conditions that are contributing the event. The outlook will be use four categories to describe an event:

  • Type (Nil, Rapid change, Extended or Reduced recovery)
  • Intensity (Low, Moderate or Severe)
  • Coverage (Isolated or Widespread)
  • Attribute (Light winds, High humidity, Rain, …)

  • A full list and more details on the definitions is detailed below

    Type: Alert threshold that has been met during the 7 day forecast period
  • Nil – no alert triggers are predicted
  • Rapid change – HLI increase >40 units in 4 hours
  • Extended – multiple days of AHLU 80 > 50
  • Reduce recovery – overnight AHLU 80 > 0

  • Intensity: Severity of the situation
  • Low – On average the AHLU 80 is below 10 within the forecast area
  • Moderate – Moderate indicates that there is some relief overnight or during the day. On average the AHLU 80 is greater than 10 but less than 50 within the forecast area
  • Severe – Severe indicates no relief expected over the next 3 to 5 days. On average the AHLU 80 is above 50 within the forecast area

  • Coverage: Geographic extent of the event
  • Isolated – some areas within a geographic region may experience conditions of Type X, depending of their local conditions (pen and cattle). No defined synoptic system to drive the event. local conditions define risk; manure depths, moisture in pen and cattle conditions. localised pockets of the forecast area are affected
  • Widespread – large areas of a geographic regions may experience conditions of Type X, local conditions still important but weather conditions are conducive to heat load. Well defined synoptic system driving event. local conditions add to risk; manure depths, moisture in pen and cattle conditions. large swaths of the forecast area are effected

  • Attribute: Describes the conditions are contributing to the Intensity of the event
  • Light winds
  • High winds
  • low humidity
  • High humidity
  • Extended rain periods (days)
  • Short rain periods (hours)
  • High daytime temperatures i.e. > 30 degrees C
  • High overnight temperatures i.e. > 20 degrees C
  • Situation specific text

  • For example the Heat Load Outlook for the Central Highlands and Coal Fields in Queensland would read:

    Central Highlands and Coalfileds: Nil – Low – Widespread – High daytime temperatures, light winds

    This outlook states that no alert thresholds have been triggered, however the risk is Low of Heat Load Event not “Nil” because large swaths of the region can expect high daytime temperatures and light winds over the next couple of days.