Australian
Weather NewsAustralian
Weather NewsSaturday 27 September 1997, 20.00 EST
A developing Tasman Sea low brought falls of up to 230mm and well below average temperatures to a large part of eastern NSW last Wednesday and Thursday, 24 and 25 September. Heaviest rain was concentrated in the southern Illawarra region around Nowra with Hampden Bridge in Kangaroo Valley scoring 232mm for the 24 hours ending 09.00 EST Thursday. Over the same period, Wottamolla received 126mm, Nowra RAN Air Station 111, Berry 105, and Robertson 85. The heaviest rain in this area fell in the early hours of Thursday morning, with Hampden Bridge receiving 58mm in one hour just before 03.00.
Elsewhere in the state, falls were more moderate, and heaviest near the coast. Steady rain fell in Sydney for most of Wednesday, with 35mm recorded in the City gauge between 09.00 and 18.00. Rose Bay had the top 24 hour Metropolitan registration with 58.8mm in the 24 hours to 09.00 Thursday. The Bureau's rain map for the 24 hours to 09.00 Wednesday and Thursday show the extent of the rain, though somewhat mask the extremes. Coming after recent falls, the rain has somewhat eased farmers' fears of an El Nino induced drought.
Due to the rain and heavy cloud cover, Wednesday was an especially cold day through most of eastern NSW. Sydney City's top temperature to 15.00 was only 12 degrees, 8 below normal, making it the coldest September day since 1908. Other substantial departures from normal were 10 below at Cessnock (12 degrees), and 9 below at Kempsey (14), Jerrys Plains (13), Gulgong (10), Lithgow (6), Katoomba (5) and Bankstown (12).
Sunday 21 September 1997, 23.10 EST
A band of thunderstorms passed through Sydney's western suburbs around noon yesterday bringing hail up to 2cm in diameter and heavy rain. Michael Bath reports that a storm developed towards the NW of Penrith, passing through Schofields with hail to 2cm. Another cell developed to the west of Oakhurst, and very quickly started to dump hail to 1cm and heavy rain by 13.00. Rain continued with close thunder and lightning for about 25 minutes with quite soft hail on and off throughout. 19mm fell. Further rain overnight gave Oakhurst a 24 hour to 09.00 this morning reading of 29.4mm. Other 24 hour falls in the storm path were Richmond Aerodrome 23, Merrylands 17.4, Oatley 19.4 and Lucas Heights 35.8.
The band of thunderstorms developed to the rear of the clearing edge of a cloudband that brought substantial rain to the state through Friday and early Saturday. It can be seen on satellite photos beginning over central NSW around mid-morning, and developing spectacularly out to sea late afternoon. The US MRF analysis charts for 10.00 EST yesterday show a very strong relative vorticity maximum bulls-eye at 500hPa (18,000 feet) just west of Sydney, together with an pool of cooler upper air over southeastern NSW. There was a band of moderate uplift on the 700hPa (10,000 feet) chart running roughly north-south through the Sydney area, associated with a pronounced upper trough. The vorticity maximum bulls-eye moved east to be around 400km east of Sydney by 22.00 at about the same strength, and was still a feature in the central Tasman on this morning's 10.00 EST chart, though considerably weakened.
Sunday 21 September 1997, 23.00 EST
Floodwaters in the South Esk River basin in northern Tasmania are now receding following last Friday's heavy rain in the northeast. Moderate flood levels were exceeded in the upper reaches of the basin during Saturday afternoon, with peaks of 1.60 metres at Mathinna about noon and 5.5m at Fingal about 20.00. Flood levels fell markedly overnight as the peak moved downstream, peaking at Llewellyn with 4.6m (minor flood height) around 18.00 today.
Saturday 20 September 1997, 13.00 EST
The rainband that has brought good falls of rain to much of southeastern Australia over the past 2 days is now moving out to sea, with its associated rather messy low pressure system now located over the southeast of the continent. Northeastern Tasmania received the heaviest falls in the 24 hours to 09.00 EST this morning, with the top registrations being 98mm at Gray and 96 at St Marys. Other heavy falls in the area were Cullenswood 67, Gladstone 54, Pyengana 65 and Storys Creek 56. A warning for minor flooding is out for the South Esk river basin as floodwaters from the rain, which eased off over the catchment around 04.30, move downstream over the weekend.
Elsewhere in southeastern Australia, the best 24 hour falls were received from widely scattered parts of NSW, but particularly around the slopes, from northeastern Victoria and southern Queensland. The Bureau map shows the extent of the rain. Best falls were Griffith 48mm, Granite Heights 46, Gunnedah 45, Mullaley 52, Woolbrook 42, Tooraweenah 42, Coonabarabran 40 and Walcha 41 in NSW, Yarrawonga 35, Whitlands 24 and Rochester and Shepparton 21 in Victoria, and Karara 42, The Deep 41 and Leyburn 40 in the East Darling Downs in Queensland.
Many of the heavier falls again occurred with thunderstorms, a substantial belt of which formed in western NSW yesterday afternoon and moved east overnight. Some heavy short-duration falls were Condobolin 20mm and Forbes Airport 11 between 21.00 last night and 00.00 this morning, Nullo Mountain in the upper Hunter 14mm between 00.00 and 03.00, Coonabarabran 20mm, Parkes 15, and Dubbo Airport 16 betwen 21.00 and 03.00, Murrurundi 13, Scone Airport 12 and Wagga Airport 13 between 03.00 and 06.00, and Armidale Airport 13 between 06.00 and 09.00.
Friday 19 September 1997, 20.15 EST
Falls of 10 to 40mm have been common over much of eastern South Australia, all of NSW and parts of Victoria over the past 24 hours or so. The rain has been caused by a broad, rather shallow low pressure system which was located over the SA/Victorian border late this afternoon, moving slowly east-south-east. Moist winds ahead of the low are converging and rising, assisted by strong upper divergence which has the effect of giving extra "suck" aloft, to enhance vertical velocity and the development of rain in moist air. Cooler patches in the atmosphere aloft have also enhanced thunderstorm development, with some serious storm activity reported from South Australia yesterday and western and northeastern NSW this afternoon. The balloon ascent from Adelaide Airport at 09.00CST this morning reported a tot-tots reading of 55. Tot-tots is a measure of instability, and 55 is a pretty high reading.
A weak low developed in a trough near the Head of the Great Australian Bight yesterday. Ceduna, to its east, reported storms at every three-hourly observation other than at noon and 15.00, with 24mm in the gauge at 09.00 yesterday mostly falling overnight. A band of storms and patchy heavy rain moved over the Eyre Peninsula during yesterday evening and across the Yorke Peninsula and Kangaroo Island and the nearby South Australian mainland early this morning. Eudunda, in the hills about 100km north of Adelaide, recorded 16mm between 18.00 and 21.00 yesterday, whilst on the Yorke Peninsula, Warooka reported 36 and Edithburgh 32 between 21.00 last night and 03.00 this morning. Cygnet River on Kangaroo Island reported 27mm for the same period. The top 24-hour totals to 09.00 CST this morning in South Australia were all from southern Yorke Peninsula and Kangaroo Island -- Kingscote 38, Edithburgh AWS 37, Warooka 36, Corny Point 34. Not far behind on the mainland were Crystal Brook and Tanunda on 27mm and Kimba on the Eyre Peninsula with 26mm, 22 of which fell in a severe thunderstorm between 06.00 and 09.00. A broad area of central south-eastern SA, and adjoining parts of Victoria, benefited from 10 to 25mm of rain to 09.00 this morning, as shown on today's Bureau map.
In NSW, a broad area of rain with some embedded thunderstorms developed in the state's north and central west overnight giving most of the region from 10 to 20mm by 09.00 EST. Narrabri West received 19mm in the 3 hours to 09.00 from a storm to give a 24 hour total of 22, while other good falls were Coonamble and Dubbo Airport 20, and Coonabarabran 21. In the 6 hours to 15.00 today, the heaviest falls continued to be reported from the north and central west, and spread to the northern half of the coast. Coonamble received a further 18mm and Coonabarabran a further 15mm from storms between 09.00 and noon. Other good falls between 09.00 and 15.00 were Gunnedah 22, Tamworth 21, Glen Innes 18, Grenfell 17, and in Victoria Yarrawonga 9, with very few places in NSW or Victoria not reporting at least a few millimetres. Between 15.00 and 18.00, the main rain area moved to southern NSW and northern Victoria, where falls of 3 to 7mm in the 3 hours were common. Ballina reported 12mm in a thunderstorm, whilst heavy storms were again reported from the far west, with Wilcannia reporting 15mm of rain and strong winds from a thunderstorm around 17.15.
A byproduct of the systems producing the rain has been some unusual temperature anomalies. In Queensland, minimum temperatures this morning from the Central Highlands to the Warrego and Far Southwest were typically 6 to 11 degrees above the September norm as warmer, tropical air moved over the region. Birdsville recorded 23 degrees, 11 above, after yesterday's maximum temperature of 38 degrees, which was also 11 above average. At the other extreme, most of northeastern NSW shivered today thanks to rain and cloud cover, with top temperatures mostly 5 to 8 below average -- Gunnedah and Jerry's Plains both reported 14 degrees, both 8 below average.
Sunday 07 September 1997, 22.00 EST
Two substantial rain events have brought much-needed falls of between 1 and 4 inches (25 to 100mm) to coastal southwest WA, the southeast quarter of SA, south central Qld, the central two-thirds of NSW, most of Victoria and northern Tasmania. The falls have come just in time to save winter crops in much of the eastern wheat belt.
In the first rain event early last week, a slow-moving low pressure area with several centres developed over SA with a rainband spawned in the moist northerly air ahead of it bringing good rain to most of southeastern Australia. There were some heavy falls in northern Tasmania where flood warnings have been current continuously since late last weekend. In the 24 hours to 09.00 Friday, Erriba reported 80mm, Sheffield 63, Barrington 73, Forthside 77, and Devonport Airport 69. The Mersey experienced moderate flooding at Kimberley with a peak of 3.4 metres about 09.00 Friday, whilst the South Esk peaked at Fingal at a minor flood level of 4.66m at 06.00 Saturday. Flooding below minor flood levels was reported from many other northern Tasmanian streams.
On Friday, a low pressure centre developed off the NSW south coast in the east of this broad low pressure area, bringing brief heavy rain to east Gippsland and far southeastern NSW. Mallacoota reported 111mm for the 24 hours to 09.00 EST Saturday, with 83mm falling between 12.00 and 21.00 Friday. Other heavy 24 hour falls were Merimbula 51mm and Brogo Dam 56 in NSW, and Point Hicks 56 and Gabo Island 65 in Victoria. An area of heavy showers from the cloud mass which brought these falls moved up the coast on Saturday afternoon giving Point Perpendicular Lighthouse on Jervis Bay 28mm between noon and 15.00.
Meanwhile, a deep low just off the southwest tip of WA on Friday moved east-south-eastwards over the weekend, to be west of Tasmania this afternoon. In WA, it brought widespread strong to galeforce winds during Friday afternoon and Saturday morning, along with thunder and hail. Rainfalls of 10 to 40mm in the 24 hours to 09.00 Saturday were the norm in the Central and South West and Great Southern. The heaviest were recorded in thunderstorms on Friday afternoon and evening in the wake of an active cold front, Perth Airport receiving 33mm between 15.00 and 21.00.
By this morning, with the low down to 980hPa and positioned south of SA, widespread light to moderate rain was again spreading over SA, Victoria and Tasmania, whilst strong to galeforce winds were being experienced across both mainland states. In SA, strong winds were reported this afternoon from many inland locations in the settled areas, the strongest wind gust reported for the state being 98km/h at Neptune Island. In Victoria, the automatic weather station on Mount Hotham recorded at top gust of 109km/h, and that on Dunns Hill, on the western flanks of Mount Dandenong, recorded 91km/h. In northern Tasmania, isolated rainfalls of 20 to 30mm overnight on already sodden ground lead to minor flood warnings being extended to all northern rivers this morning. Rain eased late in the morning, but renewed heavy falls from mid afternoon in the northeast and northwest again have streams rising.
Monday 01 September 1997, 17.30 EST
Heavy rain yesterday and overnight in Tasmania's northeast highlands has caused minor flooding today in the South Esk River basin with a peak of 1.4m at Mathinna about noon today. Heaviest falls in the 24 hours to 09.00 EST today were 120mm at Storys Creek, 84 at Pyengana and 79 at Mathinna, whilst St Helens on the east coast recorded 44mm.
Light to moderate rain has fallen yesterday and today over much of southern Northern Territory, South Australia, NSW, Victoria and northern Tasmania, with many locations reporting totals between 10 and 20mm up to 15.00 this afternoon. The Bureau of Meteorology rain maps for the 24 hours to 09.00 yesterday and today show the gradual eastward movement of the rain which is sorely needed after a very dry August and winter over most of southeastern Australia. The rain is being produced east of a developing and slow-moving low near Adelaide which is drawing moist air south from the tropics.
