20 AUSTRALIAN WEATHER. 



dition isof rare occurrence and isalways preceded by high pressures 

 without energy or grade, and consequently at a time when land 

 and sea breezes prevail. 



THUNDER AND RAIN. 



A burster rarely brings immediate rain, except when it is 

 accompanied by a thunderstorm. In the event of a three days 

 blow the downpour, if any, seldom takes place until the second day 

 and even then as is the case with all coastal ruins is heaviest on 

 the promontories, but little falls over the eastern slopes of the 

 mountains and it seldom reaches the highlands. In nearly all 

 cases the coastal region benefits by rain from the southerly half 

 of the following anticyclone. 



CONDUCIVE TO DRYNESS. 



As noted above, the burster is itself conducive to dryness rather 

 than rain, it being caused, apparently, by the hot, dry conditions 

 prevailing on the plains. The rain by which it is accompanied is 

 caused entirely by electrical disturbances. 



A GRADUAL VEERING OF WIND TO SOUTH WITHOUT A BURSTER. 



This fact may be demonstrated by studying the progress of a 

 southerly change when it is not accompanied by the "burst." As 

 the advance isobars of the approaching anticyclone reach Central 

 Australia, the northern part remains stationary while the southern 

 expands eastward with rapidity. The barometers rise rapidly in 

 Tasmania and the region of high pressure, then extends itself 

 northwards east of this coast, and thus in part surrounds a pocket 

 of low pressure. This low pressure area is then forced north- 

 wards or towards the equator, but not to the eastward, and this 

 temporary stoppage of the usual easterly motion is the precursor 

 of gales, not only in the burster season but at all times in the 

 year. In the course of the further development of this system 

 the low pressure is ultimately forced to north-east off the coast 

 of New South Wales, and the isobars trend from north-west to 

 south-east about the thirty-second or thirty-third parallels of 

 latitude. 



