Charts of the Past with Blair Trewin
BAMOS 2021 / 2022
Summer 21
17 November 1988
November 1988 marked a clear climatic shift in Australia as a significant La Niña event developed . October had been a hot and dry month over most of mainland Australia , which continued into the first few days of November ; Sydney ' s 39.2 ° C on the 3rd was their highest temperature between February 1986 and December 1990 . After that , conditions cooled significantly and moisture became abundant .
A trough crossed southeastern Australia on the 13th and 14th . A low formed in Bass Strait on the 14th before moving east of Tasmania on the 15th . Lows went on to form in a trough along the New South Wales coast on the 16th , consolidating into a single large low on the 17th , centred south of Sydney with a central pressure of 985 hPa . This low moved slowly southeast over the next 24 hours , and more quickly away from the coast after that .
The early stages of the system brought rain and cold weather to Victoria and Tasmania . Hobart ' s maximum of 10.4 ° C on the 14th was its coldest November day of the last 50 years , whilst Melbourne only reached 13.5 ° C on the 15th .
The most significant cold occurred the next day as moist southeast winds covered much of eastern New South Wales . The coldest days occurred in the Central Tablelands ; snow fell at Oberon ( where the maximum was only 5.4 ° C ) and Lithgow , and November record low maxima occurred at Orange ( 6.0 ° C ) and Bathurst ( 8.6 ° C ). Although the absolute values were higher , perhaps the most significant low temperatures were in metropolitan Sydney . Sydney itself , less than two weeks after having its hottest day of the year , had its coldest day of the year ( 12.6 ° C ) and broke its November record by more than a degree . Richmond ( 13.5 ° C ) also set a November record . Rainfall was significant although not exceptional , with Sydney recording 42.8 mm in the 24 hours to 9am on the 16th , and 34.4 mm the next day , and Canberra 36.0 mm on the 17th . The rain contributed to a spate of road accidents in which eight lives were lost . The cool air extended north in the southerly flow as far north as northern Queensland , with a November record minimum of 11.4 ° C at Croydon in the Gulf Country on the 18th .
The system also brought very heavy rain to east Gippsland in Victoria , and the far southeast of New South Wales . A number of sites on both sides of the border exceeded 150 mm on the 17th . 218.8 mm fell at Combienbar , which was a Victorian November record at the time , although it only lasted for 10 days ( before being broken at Rotamah Island in the Gippsland Lakes on the 27th ). Falls at Cabbage Tree Creek ( 195.4 mm ) and Club Terrace ( 194.2 mm ) also rank in the top five November falls for Victoria . Flooding occurred in a number of Gippsland rivers . This combined with the late November event to give much of the region its wettest November on record .
Synoptic chart for 0000 UTC , 17 November 1988