A cold front is a common feature we see on weather maps, particularly through southern parts of Australia.
It brings a change in the weather, particularly to cloud, rainfall, a sudden change in wind direction accompanied with gusty winds, and usually a sharp drop in temperature. It’s a change in air mass, from warmer conditions to cooler conditions. As a cold front moves over an area, colder air behind the change is actually quite dense and cold, it wedges in underneath the warmer air ahead of it.
This warm air ahead will actually rise, and as it rises in the atmosphere, it starts to cool and condense into cloud droplets. These cloud droplets can then form cloud and hence rainfall. Also, as the cold air moves through, we also get quite a significant change in wind direction, typically in Australia this from a north-westerly direction in the warm area ahead of the change, around to a south-westerly direction behind the change. Also, with this colder air moving over a fixed point, we get this large drop in temperature as we go from the warm air to the colder air.
The main focus of the rainfall would generally occur on and ahead of the frontal boundary.
The type of rainfall we experience can be fairly consistent in nature as it’s falling from a blanket type of cloud, which can often have embedded thunderstorm activity within it.
Once you move into the colder air behind the change, we start to get into that typical more showery weather, where we see that cumuliform type of cloud, where we get shower followed by a bit of sunshine, bit of cloud and more showers, and on and off. Cold fronts occur all year round, but they have different impacts depending on the time of year. In summer, hot and dry conditions ahead of the front, combined with gusty winds and a strong wind change, can lead to increased fire danger. While in winter, damaging winds and heavy rain are possible with the passage of a strong cold front, while snow can develop in the coldest air behind the change.
So, cold fronts are a frequent occurrence through southern parts of Australia, they’re also the major contributor to rainfall through the cooler months.
It brings a change in the weather, particularly to cloud, rainfall, a sudden change in wind direction accompanied with gusty winds, and usually a sharp drop in temperature. It’s a change in air mass, from warmer conditions to cooler conditions. As a cold front moves over an area, colder air behind the change is actually quite dense and cold, it wedges in underneath the warmer air ahead of it.
This warm air ahead will actually rise, and as it rises in the atmosphere, it starts to cool and condense into cloud droplets. These cloud droplets can then form cloud and hence rainfall. Also, as the cold air moves through, we also get quite a significant change in wind direction, typically in Australia this from a north-westerly direction in the warm area ahead of the change, around to a south-westerly direction behind the change. Also, with this colder air moving over a fixed point, we get this large drop in temperature as we go from the warm air to the colder air.
The main focus of the rainfall would generally occur on and ahead of the frontal boundary.
The type of rainfall we experience can be fairly consistent in nature as it’s falling from a blanket type of cloud, which can often have embedded thunderstorm activity within it.
Once you move into the colder air behind the change, we start to get into that typical more showery weather, where we see that cumuliform type of cloud, where we get shower followed by a bit of sunshine, bit of cloud and more showers, and on and off. Cold fronts occur all year round, but they have different impacts depending on the time of year. In summer, hot and dry conditions ahead of the front, combined with gusty winds and a strong wind change, can lead to increased fire danger. While in winter, damaging winds and heavy rain are possible with the passage of a strong cold front, while snow can develop in the coldest air behind the change.
So, cold fronts are a frequent occurrence through southern parts of Australia, they’re also the major contributor to rainfall through the cooler months.
Ask the Bureau: What is a cold front?
Explains the meteorology behind a cold front and typical impacts, including abrupt changes in temperature, wind speed and direction, and rainfall.