The Weather Man

National: Rain to give way to heatwave through the south east states.

Moderate to heavy rain across parts of Victoria and New South Wales will clear with a milder and dry southerly wind change sweeping through the south east overnight and Saturday. A high moving in behind the rain will centre itself over the Tasman sea by Sunday and become slow moving, resulting in another period of hot and dry conditions across much of South Australia, Victoria, ACT, New South Wales and Tasmania with severe conditions developing about parts of the south east mainland from Monday.

Heatwave forecast

The focus of heavy rain will shift away from the southern states and into the northern tropics with the monsoon trough remaining active across the northern Tropics and a low embedded in the trough triggering very heavy falls about parts of the Top End and Kimberley with more than enough rain to exacerbate flooding in some of these areas.

National: Burst of heavy rain for the east.

A short lived rain event is expected to drop some very worthwhile falls of 20 to 50mm across parts of Victoria and New South Wales during Friday ahead of a clearing cooler change late in the day and sweeping across New South Wales during Saturday. Severe weather warnings are current for parts of Victoria.

Heavy rain is also forecast to continue across parts of southern Western Australia but the low triggering the heavy falls is expected to weaken and dissipate by the weekend with cloud and rain clearing. Severe weather warnings are in place for parts of Western Australia

National: More heat heading for the south east states.

Forecast models are all suggesting that next week will see another heatwave develop across parts of south east Australia. By Monday a pool of hot air will be sitting over the south east inland with Adelaide and Sydney potentially impacted by a run of consecutive days with well above average temperatures. This time around Melbourne and Canberra may not be as affected compared to the recent heatwave although forecast models vary as to how far south the heat will push and how long it will linger.

Localised heavy rainfall is still possible over the southern and central inland of Western Australia on Thursday and Friday before the low triggering the rainfall breaks down and cloud and rain clears by the weekend.

Showers and thunderstorms will provide some relief from the hot weather about the south east coast of Queensland from Thursday with only isolated moderate falls about but the heat will persist over most of the inland of the state although temperatures will gradually fall through the end of the week and weekend as milder air filters through the inland and isolated showers and thunderstorms develop.

A front, trough and moist onshore wind flow will combine with a weak low developing along the trough to trigger a band of rain across eastern New South Wales during Friday before the front clears conditions during Saturday. The better of the falls in the 10 to 20mm range are most likely about the southern and central slopes and nearby plains and ranges with mostly lighter and patchier falls elsewhere.  

National: Heatwave conditions continue for parts of the continent.

Heatwave conditions continue to affect parts of the south west of Western Australia and northern New South Wales and southern and central Queensland. Conditions will abate in the south west through the remainder of the week but take longer to ease through Queensland although by Friday temperatures should be back to more normal January levels. Possible showers and thunderstorms over heat affected parts of Queensland are not expected to trigger much rainfall Over the weekend parts of the south east coastal districts and areas of Tasmania will start to experience a run of hotter than normal days.

Rainfall leading into Friday is expected to be heaviest over the inland of Western Australia and spreading south into the Goldfields before breaking up over the weekend. The monsoon trough will maintain showers and thunderstorms across parts of the northern tropics although the heavier falls look like remaining fairly isolated through the remainder of the working week. Parts of eastern New South Wales will also experience some wet weather for the remainder of the working week but heavier falls should remain associated with isolated thunderstorms especially in the north east Thursday and the southern and central ranges and western slopes Friday ahead of a clearing trend through the weekend.

National: Heat and Rain trigger dangerous conditions.

The south east of the continent will remain very uncomfortable and potentially dangerous for human health and bushfire conditions through the remainder of the working week. The heat will not be displaced until a cool change develops late Friday or early Saturday for most of the south and into Canberra during Saturday afternoon. Along with high daytime temperatures the overnight minimums will be well above average

Here are some heat statistics:

Canberra, In 2009 there were 3 days of consecutive 40 degree temperatures. This is pretty significant given there have only been 11 days above 40 in Canberra’s history. Seven of those has occurred in the last 5 years. The 1979  heat wave was significant because it had five consecutive days in excess of 37 degrees. Hottest day on record is 42.2 and was recorded back in 1968. Data courtesy ABC Canberra and BOM.

Adelaide: 2009, 13 consecutive days over 33, 6 consecutive days above 40 and 4 consecutive days over 23.

Melbourne: 2009 12 consecutive days above 28, 5 consecutive days above 30 3 consecutive days above 43.

In Northern Australia the monsoon trough is the dominant feature with Cyclone Watch for a tropical low off the Northern Territory coast. Regardless of whether the low forms into a cyclone or not heavy rain is forecast across most of the Northern Territory and parts of Queensland and Western Australia through this week and the coming weekend. 

National: High potential for week long heatwave for southern Australia.

Heat building over recent days in Western Australia will migrate east through the weekend with increasing temperatures in the south east states. Forecast models are showing no signs of a clearing pattern until next weekend at the earliest and even then it is just the coastal districts of the south east states that will get some relief with continuing heatwave conditions across the entire south east inland.

The new Heatwave Forecast from the Bureau of Meteorology which provides three levels of heatwave status, Heatwave, Severe Heatwave and Extreme Heatwave indicate that Severe conditions are expected to be experienced across the southern inland of Western Australia, Southern South Australia, southern New South Wales, most of Victoria and parts of Tasmania from Sunday. Extreme conditions will be experienced through many parts of Victoria and inland Tasmania Monday and Tuesday. More detailed information and the full forecast maps on the heatwave forecast can be found here About Pilot Heatwave Forecast and Heatwave Forecast for Australia

Extreme levels of heat will also coincide with dangerous fire weather conditions across the southern states.

At the same time the monsoon is intensifying across the north of the continent and there is the potential for one ore more tropical lows forming along the monsoon in the coming week. There is wide variations between the models. Rain forecast models are forecasting significant falls across the Western Gulf of Carpentaria, much of the Northern Territory and Kimberley and Interior of Western Australia.

National: Heatwave developing for southern Australia

A heatwave is building in Western Australia and is expected to move into South Australia and Victoria from Monday with temperatures in the mid 40’s away from coastal areas. The heat will reach New South Wales and ACT by Tuesday/Wednesday with mid 40’s temperatures. Adelaide, Melbourne, Canberra and at this stage western Sydney and parts of Tasmania will be impacted.

At this stage the forecast models are not clearing the heat before the end of the following weekend at the earliest. The Bureau of Meteorology’s new heatwave forecast models is predicting a widespread heatwave across southern Australia with a severe to extreme heatwave event in widespread areas including Adelaide, Melbourne and Canberra. Heatwave forecast

The monsoon trough is deepening across the far north of the continent and will spread west in the coming days to affect the Northern Territory spelling an end to the heat in Darwin. Moderate to heavy rain is expected to develop across the far northern tropics with the potential for tropical lows developing along the monsoon trough.

A trough in western Queensland will weaken over the next 2 days but maintain the potential for further moderate to heavy falls in parts of Inland New South Wales and Queensland today but tending lighter and contracting to Queensland on Saturday before dissipating late in the weekend.

National: Fire bans spread east with the heat.

Fire weather warnings and Total fire bans are being issued across parts of south east Australia including South Australia, Tasmania and Victoria and will most likely extend to parts of New South Wales and Queensland in the coming days as very hot and dry air spread to the eastern inland. Keep an eye on all the latest weather warnings  at the Bureau of Meteorology

Tropical Cyclone Bruce has formed in the Indian Ocean but poses no threat to the mainland although the system is forecast to reach category status Saturday. The Monsoon Trough is also developing north of the mainland and is showing signs of shifting south through the weekend and early next week although it remains a little uncertain as to whether it will cross onto the northern mainland.

National: Monsoon building to the north.

The monsoon trough is developing over Indonesia, Papua New Guinea and Timor and extends to a Tropical low which is expected to form into Tropical Cyclone later in the week to the north west of Cocos Island. It ois still uncertain as to how far the monsoon trough will move next week but northern Australia could start to come under the influence of the Madden-Julian Oscillation (MJO) with enhanced convection and increasing showers and thunderstorms. More details here.

An east moving trough is drawing very hot air ahead of it into the south eastern states with increasing temperatures peaking ahead of the trough with milder conditions developing by the weekend about the more coastal districts but remaining quite hot inland. Rainfall with showers and thunderstorms associated with the trough are not expected to amount to much more than a few millimetres in most locations. 

National: Christmas Day weather.

Forecast models are falling into line at the moment as far out as Christmas Day. The expected weather pattern appears to be a ridge of high pressure extending from a high near the south east to another in the Indian Ocean. Under the high dry and mild to warm conditions should result for most of Tasmania, Victoria southern inland of New South Wales and South Australia.

For the remainder of eastern and northern New South Wales the outlook is a little more uncertain as a moist onshore wind flow could combine with a trough to trigger cloudier conditions with the potential for showers or thunderstorms across the north east of New South Wales and potentially the southern and central inland of Queensland with isolated coastal showers in Queensland also due to moist onshore winds.

Across the northern Tropics weather conditions look to be fairly typical with showers and thunderstorms although models are suggesting a tropical disturbance somewhere between the Northern Territory and Queensland although models vary widely on its location. A Tropical feature known as the Madden-Julian Oscillation (MJO) is expected to influence the north of the continent with the monsoon developing but its location relative to the Australian mainland is still uncertain. The MJO also increases the potential for tropical Cyclones developing. Full details here. The location and strength of the MJO could also impact the rainfall potential from the trough in Queensland and New South Wales.

A trough through Western Australia will also trigger possible thundery showers and although more likely in the northern half there is some indication that the trough may draw some of the activity towards the South West districts.