Category Archives: Heat Wave

Extensive period of heat last days to even weeks

Heatwave Conditions SE Australia – 22-26 January 2021

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Heatwave Conditions SE Australia - 22-26 January 2021

A significant heatwave has gripped south east Australia over the past 4 to 5 days and is presently ending due to a cool change that is slowly crossing the southern part of the continent.

This event has been most noteworthy across the inland regions of Victoria and New South Wales although it has been strong enough to spill over into parts of Western Sydney although generally west of Parramatta.

As shown in the plots produced on the “Water and the Land”, for temperature, the worst affected regions haves been the south west part of New South Wales, Northern Victoria and South Australia.

Heatwave Conditions SE Australia - 22-26 January 2021
Heatwave Conditions SE Australia - 22-26 January 2021

There has also been a major bushfire emergency in the Adelaide Hills although a cooler change and at least 20 mm of rain has helped fire fighters to contain the blaze.

Maximum temperatures within the worst affected regions have included:-

Albury

Friday - 37.6C, Saturday - 37.6C, Sunday - 39.8C, Monday - 39.8C.

Griffith

Thursday - 37C, Friday - 39.2C, Saturday - 40.8C, Sunday - 41.7C, Monday - 40.4C.

Hay

Thursday - 38.2C, Friday - 39.9C, Saturday - 40.8C, Sunday - 43.6C, Monday - 41.7C.

Menindee

Thursday - 37.5C, Friday - 39.6C, Saturday - 41.5C, Sunday - 42.3C,

Other significant temperatures during the event include

Yarrawonga - 40.8C on Saturday.

Ivanhoe - 40.7C on Saturday,

Wilcannia and Yanco - 42C on Monday.

Walpeup (NW Victoria) - 43.9C on Sunday.

Mildura (NW Victoria) - 40.4C on Saturday and 43.3C on Sunday.

Swan Hill (NW Victoria) - 41.8C on Sunday.

The most affected regions are those that have not received the benefit of the recent rainfall.

Sydney has generally missed the worst of the heat although some has spilled into the Sydney basin affecting mainly areas away from the coast being the inland suburbs of Blacktown, Penrith, Camden, Richmond and Campbelltown. Anywhere further east has been cooler due to the sea breezes.

Even with maximum temperatures forecast to reach between 36C and 41C across Sydney, it is coming ahead of a cooler change Tuesday night / Wednesday morning.

Maximum temperatures during this event have included (Penrith east to Sydney as an east to west cross section):

Penrith - Friday - 37.1C, Saturday - 38.1C, Sunday - 39.9C, Monday 39.3C.

Blacktown - Friday - 36C, Saturday - 34.24, Sunday - 39C, Monday 37C.

Parramatta - Friday - 35.8C, Saturday - 33.3C, Sunday - 33.8C.

Sydney (Observatory Hill) - Friday - 32.9C, Saturday - 31.9C, Sunday - 33.9C, Monday 32.1C.

This gives some indication that the level of heat being experienced across the inland suburbs is not progressing east beyond Parramatta. However, it is noted that it has reached 30C at Sydney Observatory Hill on 4 days in a row and if the 36C is reached for the 26/1/2021, this would result in 5 consecutive days where it has reached 30C which is not common in summer.

A feature of this event for the Sydney basin were the development of an isolated thunderstorm on Friday afternoon (Over NE Sydney), Saturday afternoon that produced flooding at Marsden Park (Covered in a separate article) and another isolated storm cell on Sunday afternoon across the Blue Mountains as shown in the attached photo looking west. This storm did not make it into the Sydney basin but the anvil cloud cover and later additional cloud provided some relief Sunday afternoon from the heat although it made for a warm uncomfortable night.

Heatwave Conditions SE Australia - 22-26 January 2021

The cool change across the south has brought welcome rain including 16.8 mm at Deniliquin and 12 mm at Mildura and useful totals of up to 29 mm over the Dandenong Ranges (East of Melbourne). The cool change will progress towards Sydney Tuesday and conclude this current weather event late Tuesday / early Wednesday for Sydney and much of New South Wales.

Addendum 26/1/2021 - On Tuesday maximum temperatures reached 37.1C in Sydney City (Observatory Hill) making it 5 days in a row where maximum temperatures have reached 30C. Other maximum temperatures include 41.6C at Sydney Airport, 41C at Sydney Olympic Park, 40.7C at Penrith, 39.8C at Richmond and 39.1C at Horsley Park.

Most areas of Sydney has topped 38C to 41C with minor variations and it is noted that maximum temperatures were reached between 2 pm and 3pm. Increasing cloud cover from the approaching cool change after 3 pm is resulting in a slow drop in maximum temperatures and as such the worst of the heat has now passed.

It also reached 39C at Coonamble and over 36C at Dubbo but the cool change is having a significant effect across New South Wales, lowering temperatures, producing some light rain / showers especially to the south and concluding this weather event.

Storms and heatwaves – Australia a land of weather extremes – 18 to 26 January 2021

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Storms and heatwaves - Australia a land of weather extremes - 18 to 26 January 2021

The continent of Australia is often regarded as a continent that experiences some of the most variable weather extremes found anywhere on Earth. The period 18 January to the 26 January 2021 is currently living up this reputation as a number of weather extremes are occurring or have occurred during this period. These include:-

1 - Brisbane storms (SE Queensland).

During the evening of the 18/1/2020 thunderstorms traversed across Brisbane and surrounds and isolated falls exceeding 100 mm occurred. The highest rainfall totals for the 24 hours to 9 am 19/1/2021 include 191 mm at Redcliffs followed by 157 mm at Stewards Road Alert and 144 mm at Mt Cotton. This event resulted in some local flooding and flash flooding.

Much of Brisbane and south east Queensland was impacted by this event as shown in the rainfall plots provided on the “Water and the Land” for the 24 hours to 9 am 19/1/2021.

Storms and heatwaves - Australia a land of weather extremes - 18 to 26 January 2021
Storms and heatwaves - Australia a land of weather extremes - 18 to 26 January 2021

2 - Tropical storm making landfall (NW Western Australia).

A tropical storm crossed the coast of north west Western Australia and was eventually named “Tropical Storm 14” by CIMSS. This storm cross the coast earlier than expected south west of Broom prior to its final development into a tropical cyclone.

Maximum winds at the core were forecast to reach 40 knots (74 km/h) however the storm passed close enough to 2 weather stations and as such, some observations of peak wind gusts were able to be made. These include a peak wind gust of 89km/h at Bedout Island Weather Station at 10.52 pm 21/1/2021 and a peak wind gust of 74 km/h at Rowley Shoals Weather Station.

The storm made landfall within a sparsely populated area although two rain gauges / weather stations picked up rainfalls in excess of 100 mm at landfall being Mandora – 105 mm and Pardoo Station – 162 mm for the 24 hours to 9 am 22/1/2021. The next highest rainfall occurred at Anna Plains to the north west being 63 mm. This storm broke apart upon landfall although it has spread showers, storms and cloud further inland.

It is suggested that this storm has helped to force the heat of this region towards Australia’s south east in a similar manner to what occurred in late January / early February 2009.

3 - Heatwave (southern Australia).

As described in an earlier post, a significant heatwave is expected across the inland of South East Australia with a number of centres expecting 2 to 3 days in a row of 40C temperatures prior to a cooler change on Tuesday / Wednesday 26 or the 27 January 2021. This is expected to be the strongest heatwave of the summer to date.

Already a number of centres have recorded high temperatures on the first day of this weather event including 38.2C at Hay and 37C at Albury and Deniliquin.

Some updated maximum temperature forecasts include 43C at Wilcannia for Saturday to Monday, 44C for Hay for Sunday and Monday, 43C and 44C for Swan Hill for Sunday and Monday, 41C and 42C for Albury for Sunday and Monday and 39C, 38C and 40C for Penrith (Western Sydney) for Sunday, Monday and Tuesday.

The burst of heat will extend into Western Sydney but will not reach the coast.

Storms and heatwaves - Australia a land of weather extremes - 18 to 26 January 2021
Storms and heatwaves - Australia a land of weather extremes - 18 to 26 January 2021

A cooler change on either Tuesday and Wednesday will conclude this event across the south east.

Second stronger heatwave for SE Australia 21 – 25 January 2021

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Second stronger heatwave for SE Australia 21 - 25 January 2021

Days after a low intensity heatwave passed through inland south east Australia, a much stronger heatwave is forecast to develop over southern Australia in coming days. This heatwave appears to be much stronger than the first one and forecasts are suggesting that large swathes of the inland regions of New South Wales and Victoria are expected to experience a number of days above 38C.

Second stronger heatwave for SE Australia 21 - 25 January 2021

As with most heatwaves, the level of heat being forecast is not expected to reach the east coast although some of this heat is expected to spill into Western Sydney during the latter part of the event.

Forecast temperatures for this period include:-

Tibooburra (NW NSW) - Thu 22/1 - 39C, Fri 22/1 - 41C, Sat 23/1 - 42C, Sun 24/1 - 41C, Mon 25/1 - 42C.

Broken Hill (Western NSW) - Thu 22/1 - 36C, Fri 22/1 - 39C, Sat 23/1 - 41C, Sun 24/1 - 41C, Mon 25/1 - 40C.

Griffith (Riverina NSW) - Thu 22/1 - 37C, Fri 22/1 - 39C, Sat 23/1 - 41C, Sun 24/1 - 43C, Mon 25/1 - 43C.

Albury (SW Slopes NSW) - Thu 22/1 - 35C, Fri 22/1 - 38C, Sat 23/1 - 40C, Sun 24/1 - 42C, Mon 25/1 - 43C.

Dubbo (Central West NSW) - Sat 23/1 - 36, Sun 24/1 - 38C, Mon 25/1 - 38C.

Mildura (NW Victoria) - Thu 22/1 - 37C, Fri 22/1 - 39C, Sat 23/1 - 41C, Sun 24/1 - 45C, Mon 25/1 - 40C.

It appears that Melbourne will experience 1 day where the maximum daytime temperature may reach 38C being the Sunday 24/1/2021 however, southern Victoria is expected to escape the worst of it.

Second stronger heatwave for SE Australia 21 - 25 January 2021
Second stronger heatwave for SE Australia 21 - 25 January 2021

This heat should approach Sydney’s west with 41C forecast for Penrith for the 24 and 25 January 2021 but further east it will be cooler with Sydney city expected to escape the worst of it due to expected sea breezes and north east winds prevailing.

The attached plots from the BSCH are showing the potential maximum temperatures for 4 pm for Friday, Saturday and Sunday but interestingly, the burst of heat may be subdued across Central Australia due to cloud and storm activity, especially during Saturday and Sunday.

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