You may have noticed that the last two weeks have been pretty similar with fine weather most days. My observation is that it is not uncommon to see similar weekly patterns over a couple of weeks. That’s partly because the weather is largely due some major factors. One of these is the angle of incidence of solar radiation to the Earth’s surface, which changes significantly from month to month due the tilt of the Earth’s axis relative to the plane of rotation around the Sun.
This in turn means a change in the amount of energy absorbed by the Earth’s surface. For example at Brisbane’s latitude, the monthly average solar radiation falling on the Earth’s surface is 20 Megajoules per square meter per day in March. That’s equivalent to about one third of the average homes electricity use in just one day per square meter – a lot of energy. In April that falls to 16.7 MJ/m2, a 16.5 percent change. So over 2 weeks it’s about an 8 percent change. That’s sufficient to shift the latitude at which the High and Low pressure systems move across the Australian continent from west to east, and hence change the weather. That in turn changes our exposure for example to trade winds from the south-east. This is part of the reason we are about to see a prolonged south-easterly air stream over the coming week and possibly the following week.
This is how it is looking for the next 7 days. South-easterly trade winds will predominate and these tend to pick up moisture and bring showers to the coast areas in particular. The cloud cover moderates temperature, raising night-time low temperatures for this time of year and lowering the daytime maximums. So we are expecting lows around 15C and maximums of around 25C.
Source: www.seabreeze.com.au and Bureau of Meteorology
So take your brollies if you are out and about. See ya next week.
Trev The Weatherman