Rain and storms continues into new year 1-3 January 2021

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Rain and storms continues into new year 1-3 January 2021

The system that brought rain and storms to much of eastern New South Wales at the end of December 2020 has continued into the first 3 days of January 2021. One positive is that large areas of the inland has now received some rainfall from the system as expected.

Some notable storm events have occurred over recent days which has caused disruption, localized flash flooding and or wind damage. Some affected towns and cities include:-

1 - Warrnambool (SW Victoria) - Rare storm events have resulted in heavy rainfall totals of 53 mm for the 24 hours to 9 am 3/1/2021.

2 - Broken Hill (Western New South Wales). Reported in the media 2/1/2021 that a number of thunderstorms occurred some of which brought hail of between 2 cm and 4 cm including flash flooding of low lying areas.

3 - Parkes (Central West of NSW) - 2/1/2021. A thunderstorm impacted the town between 4.41 pm and 4.58 pm that brought wind gusts to 158 km/h. The local weather station recorded the peak wind gusts between 4.43 pm and 4.48 pm as well as rainfall being - 4.41 pm (0.0 mm), 4.43 pm (4.4 mm) - (That is 4.4 mm of rain in 2 minutes), 4.48 pm (21.6 mm). This is 17.2 mm in approximately 5 minutes or 21.6 mm in 7 minutes. By 4.58 pm, 31 mm had fallen from the same storm.

Other notable rainfall events within the Central West slopes and plains include 38 mm at Dubbo 115 km to the north.

Isolated rainfall totals of 65 mm fell at Portable in the Riverina of New South Wales, 62 mm at Okeh in north west New South Wales, 53 mm at Glenorchy (North west of Glenn Innes) as well as falls of 29 to 61 mm around Wollongong and Kiama on the Illawarra coast.

Last week, it was stated that there was elevated fire risk at Albury and a fire was observed on a hillside in the distance. Overnight falls of 20 mm here as well as 28 mm at Hume Dam would have been beneficial to suppress the fire danger for the short term.

The rain events and recent storms has contributed to much of New South Wales receiving average to better than average rainfall totals for the year 2020 as shown in the plots below produced on the Bureau of MeteorologyWater and The Land” site although when reviewing the Rainfall anomalies for 2020, it becomes clear that much of western and southern New South Wales is only receiving average to slightly below average rainfall. While no part of New South Wales is currently in drought, there is a risk of these areas falling back into drought for the longer term if further rainfall is not received.

Rain and storms continues into new year 1-3 January 2021

Given that the plots are for the period 1 January 2020 to the 31 December 2020, the rain and storms that impacted Broken Hill and surrounds on the 2/1/2021 will benefit the region further and the local water supply.

Rain and storms continues into new year 1-3 January 2021

Rain and storms December 29 and 30 2020 while dry in SW New South Wales.

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Rain and storms December 29 and 30 2020 while dry in SW New South Wales.

Similar to the previous post, rain continues to drench parts of eastern New South Wales while the south and west of the state remains dry resulting in wide variations of weather.

For the 24 hour period to 9 am 30/12/2020, Mona Vale in north east Sydney was drenched with 105 mm with falls of 73 to 78 mm falling in nearby suburbs.

Constant rain has also featured across other parts of New South Wales and cumulative totals are mounting.

For the period 1 December to the 30 December 2020, Horsley Park in Sydney's west has received 112 mm of rain against an average of 69.9 mm while Penrith has received 117 mm against an average of 65 mm. Furthermore, Sydney City has received 118 mm against an average of 77.1 mm.

Afternoon thunderstorms featured across Sydney and areas further north on the Monday 28 December 2020 although we were in Albury.

Interestingly, following the passage of the cold front in southern New South Wales , large banks of alto cumulus castellatus clouds dominated the sky for much of the morning although this cleared during the afternoon.

During the drive from Albury to Sydney on the 29/12/2020, we left Albury under clear skies. At Wagga Wagga, it was clear and sunny. At Gundagai, small cumulus clouds were observed. Between Gundagai and Yass, more and more clouds were observed and by the time we reached Goulburn, it was cool and cloudy with occasional drizzle patches. We reached Sydney under showery skies.

There has been a distinct dry line between the wetter eastern half and the drier western half centred close to Conroys Gap. Conroys Gap is a pass that rises approximately 650 metres in height being part of a wider north to south range of hills that divides the southern tablelands with the slopes and plains just to the west of Yass. This is where the boundary between the two air masses has been situated over the past few days.

In this instance, the eastern half has seen much of the rain while the south and west has missed the event.

Weather models are now showing and suggesting that some of the rain and storms should start to penetrate further inland thus reaching some of the drier western and southern areas during the period 31 December 2020 to the 6 January 2021. Rainfall models do suggest falls of 25 mm to 50 mm for the drier regions with continued rain for the eastern half of the state.

The attached photo taken just east of Albury (27/12/2020 looking west) is showing the typical weather conditions being experienced in southern New South Wales ahead of the most recent cool change being thin high cloud as temperatures soared close to 36C. However with elevated fire danger, fires have been a concern. The plume of smoke from a grass or bushfire is visible on the distant hills. With forecast rain over coming days, the elevated fire danger should be reduced.

Rain and storms December 29 and 30 2020 while dry in SW New South Wales.

The attached model from the Bureau of Meteorology "Water and the Land" site prepared on the 30/12/2020 is showing forecast rainfall up to the 6/1/2021. It is showing that most of New South Wales including the drier areas should benefit from the developing weather system.

Rain and storms December 29 and 30 2020 while dry in SW New South Wales.

Rain, storms, heat and wind – NSW – A state of contrasts – 22 to 28 December 2020

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Rain, storms, heat and wind - NSW - A state of contrasts - 22 to 28 December 2020

The Christmas period across New South Wales has seen significant variations of weather ranging from flooding rains to storms to hot dry and windy conditions.

During the period 22 to the 28 December, New South Wales has been a state of two halves with the north and eastern half being saturated with rain, some of which has been significant while the west and south west has been bathed in sunny and often hot conditions.

In particular and just prior to Christmas (22/12/2020), the region surrounding Tamworth and Gunnedah and other nearby towns were saturated with heavy rain with falls of up to 98 mm occurring. Much of the North West slopes and plains of New South Wales received between 50 and 98 mm of rain during this event and localised flooding of rivers and streams occurred.

During the 26/12/2020, there were thunderstorms on the ranges and the Hunter Valley of New South Wales although no such chase could be undertaken as my wife and I were in Albury on the New South Wales Victorian State border.

It is interesting to see that west of Conroys Gap (West of Yass New South Wales), the impacts of the La Nina weather pattern is significantly less. The region further west is typically dry with the grass having dried out. Near Albury, it is significantly dry and the fire risk is heightened. Where we are staying, it has been quite hot and it reached 35.6C on the 27/12/2020. Further west, it has been hotter.

Near Robinvale in North West Victoria, a bushfire was burning out of control by evening on the 27/12/2020 due to high winds and high temperatures. It reached 40C at Mildura and the high 30s across south west New South Wales on the 27/12/2020 being the areas not impacted by the recent rain events.

During the evening of the 27/12/2020, a strong cool change passed through southern New New South that brought little if any rain but brief wind gusts of 52 km/h at Albury Airport. The cool change brought little rain across northern Victoria but its impact in eastern New South Wales will be different to that of northern Victoria due to more moisture being available.

The attached rainfall plot produced on the Bureau of Meteorology "Water and the Land" website prepared on the 24/12/2020 is showing the weekly accumulative rainfall for the Murray Darling Basin. As shown, the heaviest falls have occurred across the north east of New South Wales. There is a narrow corridor focused on northern Victoria and south west New South Wales that has missed most of the recent rainfall events. This is the region that has been experiencing the high summer temperatures and where the bushfire threat is most high.

Rain, storms, heat and wind - NSW - A state of contrasts - 22 to 28 December 2020

The second plot is showing the location of the rain event to 9 am 22/12/2020 across the north west New South Wales.

Rain, storms, heat and wind - NSW - A state of contrasts - 22 to 28 December 2020