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The following is Fire Weather Data for the San Diego - Mission Trails Weather Station.

Last Updated: 6/24/2017 1:16:09 PM

Last Parse Time: 13:02

DateFWIFWI DCCBICBI DCFFDIFFDI DCDFBKDI
6/24/201726.9MD22.3LW4.5LM9302
6/23/201724.5MD22.2LW3.7LM9303
6/22/201722.7MD18.4LW5.0LM9303
6/21/201728.9MD25.5LW4.0LM9304
6/20/201729.5MD38.6LW2.9LM9304
6/19/201727.2MD55.1MD6.0LM9304
6/18/201726.8MD33.4LW5.8LM9305
6/17/201732.1MD42.2LW4.4LM9305
6/16/201734.6MD61.1MD8.5LM9306
6/15/201737.8HI63.0MD13.5HI9306
6/14/201726.9MD33.1LW4.8LM9307
6/13/201728.3MD40.7LW4.1LM9307
6/12/201721.4MD23.9LW3.7LM9308
6/11/201719.8MD13.2LW3.9LM9308

KEY FIRE INDICIES

FIRE WEATHER INDEX (FWI)
The Fire Weather Index (FWI) System is the first part of the Canadian Forest Fire Danger Rating System (CFFDRS) introduced into New Zealand in 1980. It has proved to be a suitable fire danger rating system for this country. The FWI was evaluated for several seasons before it was introduced for the 1980-81 fire season.
The FWI is based on weather readings taken at noon standard time and rates fire danger at the mid afternoon peak from 2:00 4:00 pm. Weather readings required are:
* Air temperature (in the shade)
* Relative Humidity (in the shade)
* Wind speed (at 10 metres above ground level for an average over 10 minutes)
* Rainfall (For the previous 24 hours)
The Fire Weather Index has six components:
Three Fuel Moisture Codes
1. Fine Fuel Moisture Code
2. Duff Moisture Code
3. Drought Code
Three Fire Behaviour Indices
1. Initial Spread index
2. Build Up Index
3. Fire Weather Index

CHANDLER BURNING INDEX (CBI)
The Chandler Burning Index (CBI) uses the air temperature and relative humidity to calculate a numerical index of fire danger. That number is then equated to the Fire Danger severity of either extreme, very high, high, moderate, or low. It's based solely on weather conditions, with no adjustment for fuel moisture.
CBI presented in this table is recorded at max temperature for the day and may increase during the day as temperatures rise.

FOREST FIRE DANGER INDEX (FFDI)
The Forest Fire Danger Index (FFDI) was developed in the 1960s by CSIRO scientist A.G. McArthur to measure the degree of danger of fire in Australian forests. The index combines a record of dryness, based on rainfall and evaporation, with meteorological variables for windspeed, temperature and humidity.
A FFDI of between 12 and 25 on the index is considered a "high" degree of danger, while a day having a danger rating of over 50 is considered an "Severe" fire danger rating. Above this level in 2010 a distinction was made between Forest and Grassland fuels. For Forest fuels, an FDI over 75 is categorised as "Extreme" and over 100 as "Catastrophic" (In Victoria the alternate rating name of "Code Red" has been adopted). For Grassland Fuels the threshold FDI values for the Extreme and Catastrophic Ratings was increased to 100 and 150 respectively.

Drought Factor (DF)
A key component of the FFDI is the modelling of the dryness of the fuel. This is expressed by the Drought Factor (DF), which ranges from 0 to 10. If this is multiplied by 10 and called a percent, it gives the percentage of fine fuel that would be removed by a fire under the current conditions.
The DF is based on recent rainfall and on the Byram-Keetch Drought Index (BKDI).

THE BYRAM-KEETCH DROUGHT INDEX (BKDI)
The Byram-Keetch Drought Index (BKDI) attempts to measure the amount of precipitation necessary to return the soil to full field capacity. It is a closed system ranging from 0 to 203 units (0 - 800 imperial) and represents a moisture regime from 0 to 203 millimetres (0 - 8 inches) of water through the soil layer. At 203 millimetres (8in) of water, the KBDI assumes saturation. Zero is the point of no moisture deficiency and 203 (800) is the maximum drought that is possible. At any point along the scale, the index number indicates the amount of net rainfall that is required to reduce the index to zero, or saturation.
The inputs for KBDI are weather station latitude, mean annual precipitation, maximum dry bulb temperature, and the last 24 hours of rainfall. Reduction in drought occurs only when rainfall exceeds 5mm (0.20 inch) (called net rainfall).