28 AUSTRALIAN WEATHER. 



MONOTONOUS WEATHER. 



During such droughty periods as that just referred to, the 

 barometrical changes over the whole of Australia are very slight. 

 The temperatures, however, are frequently very high inland, but 

 the diurnal ranges are not great. Locally, in Sydney, during the 

 mid-summer months, the maximum shade temperature has been 

 known to range between 80 and 86 without hot nights, for 

 twelve cpnsecutive days, with persistent north-east winds. Experi- 

 ences of this nature are monotonous for the pastoralist and 

 agriculturist, and equally so for the meteorologist, presenting as 

 they do, no interesting features for observation, and no change of 

 moment, either in weather or temperature can be anticipated until 

 the barometer shows renewed activity. 



CHANGES OF TEMPERATURE. 



Generally the greatest diurnal range of the temperature re- 

 sulting from bursters occurs in October. The mean minimum 

 temperature for this month is 55-1 so that when the maximum 

 reaches from 85 to 90 and a southerly takes place, the tem- 

 perature in some cases drops as much as 30 to 35 This range 

 is seldom reached in the hotter months, in fact it is only attained 

 when a maximum of about 100 is recorded an event of very 

 rare occurrence. 



A BURSTER OF THE POPULAR TYPE. 



An anticyclone of good energy, and one from which a popular 

 type of southerly burster lasting three days results, has a latitu- 

 dinal axis of approximately two thousand four hundred miles and 

 as it moves at the rate of four hundred miles per diem, 1 it follows 

 that if a vertical line is drawn in front of it, an observer stationed 

 in this line will record three days of southerly weather in the front 

 half of it and three days of northerly winds in the rear, due to^the 

 normal circulation about an anticyclone. This is the actual 

 experience : provided no meteorological agencies affect or modify 

 its symmetrically oval form during its passage over the Australian 



1 See Moving Anticyclones, p. 3. 



