Townsville Australia 10 Sept 2019 at 13:00

Weather report for Townsville QLD Australia for 10 Sept 2019 at 13:00:
T=27 deg C, RH=15%
Calculation: For all the following calculations the atmospheric pressure is assumed to be 101.325 kPa and the efficiency of evaporative cooling is 30%:
With evaporative cooling of 30% efficiency the air will be cooled 4.22 deg C to 22.78 deg C. 

Volumetric heat capacity of air before cooling is 1.185 kJ/(m^3.degC)

The mass of water required to do the evaporative cooling is 2035 tonnes per cubic km.
RH after evaporative cooling will be 29.38%. 

Danger of fire. The greater the Chandler Burning Index the greater the danger of fire:
Before evaporative cooling: Chandler burning index is 124.9 (extreme danger of fire)
After evaporative cooling: Chandler burning index is 60.6 (moderate risk of fire)

Dew Point:
Dew point before evaporative cooling is -1.82 deg C
Dew point after evaporative cooling is 4.02 deg C
Using Espy's equation for lifted condensation (height air must rise for clouds to start forming):

Lifted condensation level  (LCL) before evaporative cooling is 3603 m
Lifted condensation level after evaporative cooling is 2345 m.
Vapour pressure deficit (VPD). Usually VPD should be between 0.45 kPa and 1.25 kPa: Danger zones are VPD is less than 0.4 kPa and VPD is greater than 1.6 kPa
Before evaporative cooling VPD is 3.03 kPa
After evaporative cooling VPD is 1.96 kPa