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Wednesday 18 October 2000

Gales, torrential rain as Low slams Adelaide and surrounds
Cold in southern WA, central and southern NT
Above: The surface chart for 9.30am CST shows the low crossing the SA coast near Kangaroo Island, with a major trough extending into the NT. BoM
Below: The infrared satellite image for the same time. Cloud can be seen streaming around the back of the low. In the NT, the thick cloudband kept daytime temperatures well below normal. The yellow/orange spot in central NT marks high (cold) cloud tops above a storm that gave Pigeon Hole, near Victoria River Downs, 62.6mm for the 24 hours to 9am. JCU
A low pressure system that developed in the heat low over Western Australia two days ago and moved slowly ESE brought a day of heavy rain and gale force winds to Adelaide, Kangaroo Island, Eyre Peninsula and nearby areas today. October one-day rainfall records were broken at several centres, with Port Lincoln recording 45.6mm for the 24 hours to 9am, 7mm higher than its previous record in over a century of rainfall readings (see panel below and for 19 October for details of other records).

The low deepened to 997hPa overnight in response to colder air moving in aloft, and picked up substantial moisture from waters around Eyre Peninsula which are currently 1.5 to 2 warmer than normal. The first band of heavy rain crossed Kangaroo Island, the Fleurieu Peninsula and Adelaide Hills overnight, bringing falls of up to 60mm to 9am at Second Valley, on the coast 70km south of Adelaide. Most other centres in the area recorded more than 40mm -- unusually high for the area.

As the low crossed the SA coast near Kangaroo Island and moved slowly towards western Victoria, the rain band wrapped around its southern side and returned to the same area from the south to give even heavier rain during the afternoon and evening. The Clare Valley and Northern Mount Lofty Ranges caught the heaviest falls, with 24 hour to 9am Thursday totals of 62.4mm at Watervale and 56.4 at Mintaro in the Clare Valley, and 59.2 at Laura in the Northern Mount Lofty Ranges east of Port Pirie. Flooding was reported between Clare and Leasingham, parts of the Main North Road were under water, and at least three houses had to be sandbagged at Watervale. Cape Willoughby, at the eastern end of Kangaroo Island, recorded 50mm to 9am Thursday, its heaviest October one-day fall in 111 years of record, and following on from a near-record-breaking 42mm to 9am today. Victor Harbour, with 42.4mm, came within 0.2mm of equalling its 116-year October record, while Neptune Island had the distinction of exceeding its record over 33 years on two consecutive days, with falls of 36 and 34mm. Among the heaviest totals for the 2 days to 9am Thursday were 93.4mm at Yankalilla on the southern Fleurieu Peninsula, and 92mm at Penneshaw, Allandale and Cape Willoughby, all on Kangaroo Island.

As the low moved slowly into Victoria, the tightening pressure gradient between it and a high over the Bight brought gale force winds across the area from late afternoon into the night. Winds gusted to 113km/h at Neptune Island, and 85km/h inland at Clare. In Adelaide, trees and powerlines were downed, causing over 10,000 homes to lose power, while roofs were damaged and roads blocked by debris and flooding. Over 300 emergency calls were lodged, with the worst damage reported from North Beach on Yorke Peninsula, where a shack's roof was blown away and a refrigerator lifted into a neighbouring yard.

Temperatures across central and southern Northern Territory today were 12 to 15 below the October average as a huge cloudband, lying in the northern extension of the trough that crossed SA today, kept sunshine away. In southern WA, both Albany Airport and Salmon Gums, between Norseman and Esperance, equalled their October record low minimum temperatures this morning, as high pressure moved in behind the cold airmass that is sweeping across SA today.

Today's highest rainfall totals for the 24 hours to 9am

74.0 Spring Creek Kununurra WA
62.6 Pigeon Hole NT
60.0 Second Valley Parawa SA
55.8 Sharon Parawa SA

Other heavy falls in SA:
55.2 Bridgewater
54.6 Lenswood Res Centre
49.8 Myponga
46.4 Heathfield
45.6 Port Lincoln
45.6 Mt Compass
44.6 Yankalilla
44.0 Kingscote AP
43.6 Woodside
43.0 Allandale
43.0 Lobethal

High falls for other periods:

Western Australia:
Halls Ck AP:
21.4mm in 34m to 7.30am

South Australia:
Port Lincoln:
25mm in 6h to 3pm
Neptune Is: 20mm in 6h to 3am and 32mm in 6h to 3pm
Clare: 37mm in 6h to 9pm
Maitland: 49mm in 12h to 9pm
Kingscote AP: 29mm in 6h to 3am
Kingscote town: 23mm in 3h to 3pm
Cape Willoughby: 30mm in 6h to 3am and 30mm in 6h to 9pm
Parawa: 33mm in 6h to 3am and 42mm in 6h to 9pm

New South Wales:
Wagga AP:
19mm in 3h to 9pm
Griffith AP: 17mm in 19m to 5.08pm

Today's highest & lowest temps

Wind (mean refers to the average windspeed over 10 minutes; gust is the highest speed recorded):

Neptune Is SA: mean 89km/h at 1.28pm and 2pm, gust to 113km/h at 1.40pm
Clare SA: gust to 85km/h at 4.30pm
Cape Willoughby SA: gust to 91km/h at 7.30pm
Falls Ck Vic: gust to 102km/h at 12.44pm
Mt Hotham summit Vic: 109km/h at 1pm
Kilmore Gap Vic: gust to 93km/h at 11.40am

Records set this day

Highest daily rainfall for October (previous record and years of computerised record shown in brackets):
Port Lincoln SA: 45.6 (37.0, 101)
Neptune Is SA: 36.0 (25.1, 33)
Gum View Elliston SA: 39.0 (31.0, 33)
Lenswood Res Stn SA: 54.6 (50.0, 32)

Lowest minimum temperature for October (previous record and years of computerised record shown in brackets):
Albany AP WA: 1.0, equalling previous record in 35 years
Salmon Gums Res Stn WA: -2.0, equalling previous record in 29 years

 

Maximum Minimum
39.0 Wyndham AP WA 28.0 Wyndham AP
5.7 Mt Hotham Vic -3.0 Crackenback NSW

Greatest variations from normal

Maximum Minimum
+6.4
32.2 Eneabba PO WA
+9.1
24.4 Thargomindah PO Qld
-14.9
23.0 Elliott NT
-14.7
20.0 Tennant Creek AP NT
-12.1 Jervois NT
-9.6
-2.0 Salmon Gums WA