SIGNIFICANT WEATHER - MAY 1997

INTRODUCTION

TROPICAL CYCLONES

Western Australia

A low, well to the west of the Cocos (Keeling) Islands, developed into tropical cyclone RHONDA on the 11th. The system move along a generally south-eastward path and by the 14th had intensified to be a severe tropical storm (category 4) while approximately 400 km to the south of Cocos.
Continuing in a similar direction, TC RHONDA weakened during the 15th and 16th and dissipated into a rain-bearing depression early on the 17th when located approximately 400 km to the west of Carnarvon.
TC RHONDA did not have a direct effect on Cocos or WA and only light rains (mostly less than 10mm) were generally registered in the Gascoyne, Murchison and Pilbara. However, several localities in the west Gascoyne recorded higher totals including Carnarvon (39mm) and Minilya (to the north of Carnarvon, 46mm).

SEVERE STORMS

New South Wales

An East Coast Low produced gale force winds, large seas and heavy rainfall along parts of the NSW coast over the weekend of the 10th/11th. A Sydney Ports Corporation buoy off Botany Bay recorded maximum wave heights of 16.7m on the 10th. Strongest wind gusts recorded included: Norah Head 107km/h; Sydney Airport 106km/h; Point Perpendicular 102km/h; Botany Bay 98km/h; Bellambi 91km/h; and Ulladulla 94km/h. The strongest mean wind speeds included 81km/h at Norah Head and Botany bay and 74km/h at Sydney Airport. Rainfall totals for the 24hrs to 9am on the 11th included 131mm at French's Forest and 124mm at Norah Head. The State Emergency Service received 1000 calls for assistance with most relating to roof damage and fallen trees. Local flooding was reported in many areas and coastal erosion occurred near Wyong and Terrigal, on Sydney's northern beaches and near Nowra. A surf club storage shed in the Royal National Park was destroyed and much equipment was lost. Many yachts and other boats were washed ashore.

FLOODING

Tasmania

Heavy rain during the first three days of May caused flooding in the north of the State. The worst flooding was along the Meander River with sandbags used to stop flooding in Meander and the evacuation of the Deloraine caravan park.

WIND

Western Australia

On the 23rd, tree and minor building damage occurred near Busselton during the passage of an active cold front. Cape Naturaliste, to the north- west of Busselton, recorded wind gusts to 100km/h.

TEMPERATURE

Lowest Daily Minimum Temperature for May

                                   Previous          Years of
Station            Actual   Date    Lowest    Year    Record
                     øC               øC
Western Australia

Meekathara          12.0     9      12.8      1970      47

Lowest Mean Minimum Temperature for May

                              Previous             Years of
Station             Actual     Lowest      Year     Record
                      øC         øC
Queensland

Coen Airport        17.9        18.5       1971       30
Mount Isa           11.3        11.4       1971       32

RAINFALL

Western Australia

Several systems of tropical origin produced rainfall about parts of Western Australia during May. On the 4th and 5th thundery showers occurred in the Pilbara, Gascoyne and interior as a northwest cloudband moved across the region. Another cloudband interacting with a mid-level disturbance brought record daily rainfall to parts of the Kimberley between the 9th and 13th, including Kuri Bay registering 250.4 mm on the 11th. Numerous other localities in the West Kimberley and De Grey reported daily totals of more than 50 mm while the cloudband persisted over northern parts of the state.

Highest Daily Rainfall on Record for May

                                   Previous              Years of
Station            Actual   Date    Highest      Year     Record
                     mm               mm
Western Australia 

Broome             125.6     10      119.4       1964       57
Cygnet Bay         124.0     13      115.6       1964       34
Kuri Bay           250.4     11      210.8       1970       31

Highest Monthly Rainfall on Record for May

                                 Previous             Years of
Station                 Actual    Highest     Year     Record
                          mm        mm
Tasmania

Forthside                202.0     180.6      1988       31

Western Australia

Broome                   267.8     175.8      1950       57
Carnegie                  91.6      89.6      1970       41
Cygnet Bay               365.6     217.4      1968       34
Kuri Bay                 425.8     324.1      1970       31
Mandora                  214.0     166.8      1988       84