Fire Weather Index (FWI):   Forecasts

The following map shows the FWI for 08 Jan 2013 (updated 08/01/2013 at 15:41 AEDT).

The following map indicates how often conditions as severe as this occur at a location (based on percentiles of the FWI). Higher values indicate more severe conditions in terms of the local climate.


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The following maps show values of the three Fuel Moisutre Codes of the FWI:

- the Fine Fuel Moisture Code, representing the moisture content of fine fuels and litter on the forest floor,

- the Duff Moisture Code, representing the moisture content of loosely compacted decomposing organic matter,

- the Drought Code, representing the moisture content of deep compact organic matter of moderate depth.

Percentile maps are also shown to indicate how often conditions as severe as this occur at a location.







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The following maps show values of the two Fire Behaviour Indices of the FWI:

- the Initial Spread Index, representing the influence of wind speed and fine fuel moisture on fire spread,

- the Build-Up Index, representing the availability of the deeper or larger-sized fuel.

Percentile maps are also shown to indicate how often conditions as severe as this occur at a location.





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The following maps show wind speed, relative humidity and temperature, as used by the FWI.

Percentile maps are also shown to indicate how often conditions as severe as this occur at a location.







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The following map shows rainfall as used by the FWI (when available, as it is based on observations rather than forecasts).

A percentile map is also shown to indicate how often this amount of rainfall occurs at a location.



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Fire Danger Ratings for the FWI values are

* Low: 0-14

* Moderate: 14-35

* High: 35-64

* Very High: 64-122

* Extreme: 122-232

* Catastrophic 232+

corresponding to McArthur FFDI classifications of Low: 0-5, Moderate: 5-12, High: 12-24, Very High: 24-50, Extreme: 50-100 and Catastrophic 100+, produced by matching percentiles of the FWI to percentiles of the FFDI throughout Australia.

- The FWI represents the peak daily intensity of a spreading fire as the energy output rate per unit length of fire front.

- The FWI (and sub-indices) are not representative of fire danger and are only indicative of fire weather conditions.

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Notes on percentiles:

- The percentiles shown in the above maps are calculated individually for each location, based on 9 years of data (from the years 2000-2008).

- The percentiles provide an indication of how frequently the value of the parameter could be expected to occur at a given location. For example, if the FWI value has a percentile of 99, this suggests that FWI values as high or higher than this would typically occur only about 3 or 4 times a year at that location.

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Notes on input data:

- NWP forecasts are used for all parameters except for rainfall which is derived from observations.

- Wind speed, relative humidity and temperature are foercast for noon Western Daylight Saving Time (i.e. 1400 Eastern Daylight Saving Time).

- Rainfall is the total for 24 hours up to 9 a.m. at the regional local time (including daylight saving).

- Some inland areas are intentionally blank due to insufficient rainfall observations.

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Comparison with the McArthur FFDI:

- The FWI shows broad similarities to the McArthur FFDI: both indices are most sensitive to wind speed, then secondly to relative humidity, thirdly to temperature and finally to drought (i.e. either the Drought Factor for the FFDI or the Drought Code for the FWI).

- Some differences are apparent on a finer scale: the FWI is relatively more sensitive to wind speed and rainfall, and less sensitive to temperature and relative humidity, than the FFDI.

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Further information on the McArthur FFDI and on the FWI System can be accessed here: Dowdy et al. (2009).

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Please note that the Disclaimers for the Bureau of Meteorology and CSIRO apply also to this site.
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