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BAMOS May 2026
Charts of the Past with Blair Trewin 1 May, 1997
1997 is best known climatically for its very strong El Niño. In Australia, the rainfall impacts were more limited than in some other comparable El Niño events, and some of the most significant dry periods of the year occurred before the El Niño had fully developed. March and April, particularly April, were very dry months for much of southeast Australia. April was the driest month on record at any time of year for New South Wales and the Murray-Darling Basin, and Mildura had its longest dry spell on record, an 82-day period extending from 11 February to 3 May.
Much of April was dominated by strong high pressure over southern Australia, with the last major blocking high in the sequence forming from the 25th onwards. This blocking high moved gradually eastwards and was centred in the Tasman by the end of April, directing a northwesterly airstream over much of southeastern Australia. It then strengthened as the first in a sequence of fronts approached at the start of May.
A warm spell that had built up through the last few days of April reached its peak on 1 May, and with the timing at the start of the month, numerous records were broken, most notably in eastern Victoria and parts of Tasmania. Bairnsdale reached 29.4 ° C, at the time a May record for southern Victoria( since broken in 2018), and other key Gippsland sites set May records, including Sale( 28.3 ° C) and Wilsons Promontory( 25.7 ° C). Flinders Island( 27.4 ° C) had a site May record and the highest May temperature in Tasmania since 1936. There were also some May records in southern inland New South Wales, including Hay( 30.0 ° C) and Deniliquin( 29.2 ° C). The temperatures at Hobart( 25.7 ° C) and Launceston Airport( 21.8 ° C) set May records at the time, although both were surpassed in 2026.
With strengthening winds and the very dry antecedent conditions, fire weather conditions were also highly unusual for so late in autumn. A total fire ban was declared for the Central and Southwestern districts of Victoria, the only time this has occurred in May, although no serious fires occurred. The front in the west brought some rain to western parts of Western Australia, although falls were mostly light, with only a few sites receiving more than 10 mm.
Generally, northwesterly flow persisted until the 4th, but an increasingly moist flow and approaching fronts brought a wetter regime to the region. This was especially significant in northern Tasmania. Breona, on the north side of Great Lake, received 275.2 mm over the three days 2−4 May, and Quamby Bluff received 154.0 mm on the 4th. This resulted in flooding, particularly in the Meander River, with evacuations occurring in Deloraine. While falls were lighter on the mainland, much of southwest Victoria and southeast South Australia received 25−50 mm over the three days, with a peak daily fall of 75.6 mm on the 4th at Wyelangta in the Otway Ranges. Temperatures remained above average, with Melbourne recording minimum temperatures above 15 ° C on each of the first four days of the month. An upper-level low off the southern Queensland coast also brought significant rain to coastal regions there and northern New South Wales, with totals of up to 150 mm on 5 May in the Gold Coast hinterland.
Synoptic chart for 0000 UTC, 1 May 1997