Strange clouds and storms swirl over Sydney

Spectacular mammatus or 'mammary clouds' form over Sydney as storms swirl nearby

ABC

3 January 2019

As hail, heavy rain and storms continue to hit multiple areas across New South Wales, keen weather-watchers have documented unusual cloud formations called mammatus, or "mammary clouds", in the skies over parts of Sydney.

A number of people have posted snapshots to our ABC Weather Obsessed Facebook groupdocumenting the clouds.

Mammatus clouds appear as rounded pouches or bulges hanging underneath the base of a cloud, and are generally associated with severe weather or storm activity.

The word "mammatus" is a Latin term that means breast, udder or mammary gland, and the clouds form their distinctive shape when cold air sinks below the cloud.

Mammatus clouds appear as rounded pouches or bulges hanging underneath the base of a cloud, and are generally associated with severe weather or storm activity.

The word "mammatus" is a Latin term that means breast, udder or mammary gland, and the clouds form their distinctive shape when cold air sinks below the cloud.

PHOTO: Mammatus clouds photographed over Manly Dam on Sydney's northern beaches. (Supplied: Laurie Wilson, Facebook)

According to the Bureau of Meteorology (BOM) Storm Spotters Handbook, the clouds are "dramatic, beautiful adornments, especially when side-lit".

PHOTO: Mammary-shaped clouds seen over Sydney's Olympic Park. (Supplied: CJ Lightning, Facebook)

Mammatus clouds are often associated with extreme weather, but when they are formed in the sky it merely indicates "descending pockets of small droplets or ice crystals from an anvil surface", BOM said.

PHOTO: Unusual mammatus clouds over North Curl Curl beach on Sydney's northern beaches. (Supplied: Lorraine McManus, Facebook)

And, according to BOM, while they might look pretty dramatic and often appear around the same time as severe storms, mammatus clouds themselves are perfectly harmless.

PHOTO: Mammatus clouds in the sky above a suburban Sydney street. (Supplied: Debbie Barnes Reid, Facebook)

Australian weather

Meanwhile New Zealand is enjoying what must be some of the most equitable (if slightly cool) weather on the planet.

No summer rain as Victoria keeps baking

The Age,

3 February, 2014

A cardigan might be in order for Melbourne's 35-degree Monday, because by the evening commute, the temperature is expected to drop down to the low 20s.

The cool change is expected to breeze through about midday as low cloud cover and a south to south-easterly wind change brings the temperature down to about 26 degrees by about 3pm.

Senior forecaster Scott Williams said the temperature would drop.

"It is almost going to be cardigan weather as people are going home with a significant change," he said.

Tuesday is expected to provide the only reprieve from the 30-plus degree days this week as temperatures rise on Wednesday to 31 degrees, with 38 degrees expected on Saturday. Temperatures in the north of the state are tipped to drop from the low 40s to low 30s on Tuesday.

Mr Williams predicted Melbourne's weather would remain mostly hot, with temperatures over 30 and into the high 30s through February and into early March.

"We are not going to get rid of the heat in any great rush," Mr Williams said.

He said Melbourne had a very dry January, with just 13 millimetres of rain compared to the 47mm average. The highest rainfall day was January 25 with 5mm.

Mr Williams said normally a major rain pattern from the centre of the continent would push south to Victoria which would cool and refresh the state and add to rainwater reserves.

He said monsoonal weather in Queensland had little prospect of reaching Victoria.

"After a not particularly hot start to summer, it is shaping up to be a very intense rest of the summer," Mr Williams said.

December also had lower than average falls with 39mm recorded against the average of 59mm. The last "decent" rain was on December 10, when 10 mm fell, he said.

Mr Williams said the low rainfall was not as low at 2009 when there was just 0.8 mm of rain for January.