Parts of coastal New South Wales could receive up to 120mm of rain over the weekend with heavy falls expected from late Saturday.
The rainfall comes 10 days after Sydney broke a century-old temperature record, with 184 days of temperatures exceeding 20C.
A low pressure system is expected to form offshore that will bring heavy rain and possible thunderstorms to areas including the Illawarra, Sydney and the Central Coast.
Severe Weather Warning issued in #Illawarra and #SouthCoast between #JervisBay and #BatemansBay for possible HEAVY RAIN and DAMAGING WINDS tonight and Sunday morning. 6hr totals between 80-120 mm possible. Warning at: https://t.co/EIDIQ98q7d pic.twitter.com/1mwyx5ui9O
— Bureau of Meteorology, New South Wales (@BOM_NSW) April 29, 2023
Scattered showers and storms could occur during the day on Saturday as a result of an earlier rain band but coastal areas are forecast to see much larger rainfall totals from Saturday evening and into Sunday.
“There’s still some uncertainty around it – it depends how close the low pressure system is to the coast,” Miriam Bradbury, a senior meteorologist at the Bureau of Meteorology, said.
“But widespread falls of 20-30mm are expected today and tomorrow about those southern coasts.”
Areas south of Sydney, including the Illawarra region could receive up to 100mm across the weekend.
“Especially if we get thunderstorms pushing through, that will push those rainfall totals up,” Bradbury said.
“We just recommend that everyone keeps an eye on the radar and is also aware that whether it’s 20mm or 50mm of rain it could produce hazardous driving conditions.”
The low pressure system could also bring strong winds, with gales expected in southern marine areas around the Illawarra to the Eden coasts with the potential for strong winds pushing onshore.
On Saturday afternoon the bureau issued warnings for heavy falls and dangerous winds from Nowra through to Batemans Bay on Saturday night.
Six-hourly rainfall totals of between 80 and 120mm were predicted, with strong to damaging winds of between 50 and 70km/h, and 90km/h gusts.
Areas at risk include Batemans Bay, Huskisson and Ulladulla with conditions expected to ease on Sunday afternoon.
The NSW State Emergency Service has urged people to keep track of weather updates, prepare their homes and avoid driving if possible.
“Localised flash flooding could result in roads being closed at short notice. Please do not take the risk and find an alternate route if you need to travel,” SES assistant commissioner Nicole Hogan said.
“Landslips are also possible, and I would urge the public to remain vigilant.”
Despite the weekend forecast for coastal NSW, the longer term outlook for the majority of Australia is for below median rainfall through the remainder of autumn and into winter.
May to July days are likely to be warmer than median for most of the country and there is the possibility of both an El Niño developing later in the year as well as a positive Indian Ocean dipole.
Some models are raising the possibility later this year of an extreme, or “super El Niño”, that is marked by very high temperatures in a central region of the Pacific around the equator.
The last extreme El Niño in 2016 helped push global temperatures to the highest on record, underpinned by human-caused global heating that sparked floods, droughts and disease outbreaks.
