Maleny Weather

On Tuesday June 22 the sun rises at Maleny at 6.38am and sets at 5.04pm, giving 10 hours and 27 minutes of official daylight. This is our shortest day of the year when the sun is directly overhead at the Tropic of Cancer.  Known as the Winter Solstice or Mid-winter’s Day, it is when a ‘night’ lasts for 24 hours on all places within the Antarctic Circle,

The question often asked is if the winter season in Australia covers the months of June, July and August so why isn’t our mid-winter’s day in July?

In many countries of the world the seasons are defined by the solstices and the equinoxes. For example our winter season is from June 21 to September 22.

The reason our mid-winter‘s day s near the beginning and not the middle of the season is due to the lag of the season – the time-lag between the movements of the sun and temperature and response of the land masses and oceans. In northern Australia the four seasons are of little relevance because the length of day doesn’t vary a great deal and at midday the sun is always high in the heavens. Here they have’ wet’ and ‘dry’ seasons – the monsoonal climates.

This South Pacific storm formed between 1^st and 4^th June 1994, and while not unusual, it affected a large number of yachts on route between New Zealand and Tonga and led to New Zealand’s largest air/sea rescue operation. Six yachts were abandoned and their crews picked up and one with its crew of three was lost.

This was not the cyclone season and the storm that developed was never officially named as such. In any case it had no core of central warm air characteristic of cyclones and hardly reached gale force winds while it was in the tropics.

None the less, its effects in the subtropics were devastating.

On June 2^nd, a slight kink in the isobars of the synoptic chart near Vanuatu was the only indicator of what was about to take place.

The low pressure system developed and started to move south. Of particular significance is the area of high pressure over New Zealand that brought in a supply of cold, low level air from the Antarctic. Cold air does not mix easily with warm and the effect of this inflow was to force the existing warm air upwards. An upper level system was active and withdrew rising air faster than the incoming cold stream was able to replace it. Barometric pressure of the surface was reduced still further as the system increased in size.

This phenomenon of cold air being drawn into a deepening low pressure system is sometimes known as meteorological ‘bomb’

source Bureau of Meteorology