TAS: Records smashed as torrential rain brings flash floods to Hobart
Fri 11 May 2018

Rain and thunderstorms brought the heaviest rain on the record books to a large part of SE TAS overnight Thu 10^th/Fri 11^th May. The heaviest rain fell in during the middle of the night around Hobart and the Wellington Range behind the city. The BoM said it was caused when "A complex low pressure system crossed Tasmania on the 10^th, then deepened to the northeast during the 11^th bringing [a] strong, gusty and moist southerly flow over the state."

Some of the rainfall totals were unbelievable for Tasmania, and more akin to heavy tropical downpours. The weather station on Mount Wellington Pinnacle (kunanyi) reported 236.2mm in the 24 hours to 0900 11^th, the second-highest daily fall ever recorded for TAS in May. Leslie Vale, 12km SW of Hobart and on the southern side of Mt Wellington, reported 226.4mm, the third highest May daily rainfall ever in the state. Some idea of the intensity of the rain on Mt Wellington summit is given by their 7-hour total of 151.8mm between 2100 10^th and 0400 11^th, and of that 58.4mm fell in the hour from 2200 to 2300 11^th with 20.2mm falling in 10 minutes to 2240. Conditions on the summit must have been unbearable, because, on top of the torrential rain, wind gusted to 132km/h at 2000.

The Hobart BoM Regional Office in Ellerslie Road, close to the centre of the city, recorded 129.2mm for the 24 hours to 0900 11^th, nearly trebling its previous May record of 47.0mm in a 125-year history. 43mm of that fell in just one hour. Also to 0900, the Bureau's office recorded its windiest 24 hours in May in a 68-year history with an average of 39.1km/h. The large number of May and all-time records broken indicate how widespread and exceptional this event was.

The resulting fast-flowing flash flooding off the mountains caused widespread damage to buildings, vehicles and public infrastructure, with estimates by the end of May indicating nearly $30m in insurance claims in addition to nearly $30m in damage to municipal infrastructure. The Guardian gave this detailed account of the event, including social media posts while it was happening. This video compilation by the ABC shows the flash flooding in progress. Over 13,000 properties lost power, while 19 schools and the University of Tasmania's Sandy Bay Campus were closed due to flooding or safety concerns [SMH].

In the aftermath, well documented in this ABC photo gallery, the Insurance Council of Australia declared the event a catastrophe, opening a hotline to help prioritise mounting claims. The ABC opened a live reporting page, and Tasmanian emergency services briefed the media. As usually happens, early reports during the clean-up underestimated its severity, but by Monday 14^th a clearer picture was emerging, with insurance claims put at $20m and rising. [ABC]

The day after the event, Adam Morgan, Senior Meteorologist at the BoM, wrote in The Conversation about the meteorology behind it, and the difficulties in forecasting such an event. On a lighter note, The Guardian cartoonist, First Dog on the Moon, himself a resident in the affected area, provided his take on the events of the night.

WA: Heat builds ahead of front Sun 3 Jun 2018 - June heat has been building across much of the WA inland over the past four days. A nearly stationary high pressure system over the southeastern states has pushed dry air from the tropical NT into the state, giving much of inland WA day and night time temperatures 4 to 8° above the June average, and up to 9 above at Newman on Friday morning. While most coastal areas were below or close to normal, the high temperatures broke through to the Pilbara and Gascoyne coasts on Friday 1^st. Carnarvon recorded a top temperature of 31.6 on Sunday 3^rd, 8.1 above average and only 0.6 off its hottest June day in 72 years of observations.

AUS: Failure of May rains puts winter crops at risk Fri 1 Jun 2018 - Australia's May average rainfall nationally came in at a mere 8.7mm, or 69% of average, making it the third driest May in the 119-year national record, according to the BoM's National Monthly Summary. It was only 0.9mm shy of the record dry May of 2008. QLD, NSW, SA and WA were all hard hit, with QLD receiving only 17% of normal May rain, NSW 25%, WA 26% and SA 42%.

Unfortunately, some of the driest parts were the farming areas looking for an autumn break to get winter crops in before the sowing window closed. These included large areas of southern WA, southern QLD and northern and eastern NSW. Fairfax Media reported that winter plantings were expected to be down 11% in QLD and 7% in NSW compared to 2017.