Monday, 31 October 2011 - Monthly Climate Summary for Western Australia - Product code IDCKGC11R0

Western Australia in October 2011: Third wettest October on record

• Rainfall: 3rd wettest October for WA; above average for southwest WA
• Maximum temperature: Near average for WA
• Minimum temperature: Above average for WA; 3rd warmest for southwest WA.

Details Extremes Records Summaries Important notes the top

Rainfall

October 2011 rainfall was above to very much above average for most of WA, with sites in the Central West, Central Wheat Belt, Great Southern, Southeast Coastal, Goldfields, western Interior, and Kimberley registering their wettest October on record, and notably a significant number of these sites have over 100 years of rainfall recording history. Below average rainfall was mainly confined to western parts of the Southwest district, and parts of Pilbara (see October 2011 rainfall totals & deciles. When averaged across the state, October 2011 was the 3rd wettest October on record for WA (comparable records commenced in 1900), whilst the Southwest Land Division (SWLD) recorded its 7th wettest October.

A low pressure system over central WA combined with a middle level disturbance in the first few days of the month to bring widespread rainfall to the southern half of WA. Moderate to heavy rainfall with daily rainfall totals over 40 mm was reported at a number of locations in the southern Gascoyne, Central West, and Central Wheat Belt on the 3rd, with a few sites recording their highest daily October rainfall as a result, whilst further significant falls were reported in the Goldfields in the 24 hours to 9am on the 4th. Showers and thunderstorms brought isolated moderate falls to the SWLD, Goldfields and Eucla between the 7th and 12th, with Windrush in the South Coastal on the 9th, and Goomaling in the Central Wheat Belt on the 11th, recording October daily rainfall records. A cold front on the 18th brought some moderate falls to the SWLD, and a series of middle level disturbances brought showers and thunderstorms to large parts of the state in the last 11 days of October as moderate to heavy falls were reported and many sites in different regions of the state recorded their highest daily rainfall for October on record.

Maximum temperature

October 2011 maximum temperatures were near average across most of WA. Areas of above to very much above average maxima were observed in the western coastal strip south of Shark Bay, with mean maxima up to 2 °C above normal in western parts of the Lower West and Southwest. Below average maxima were experienced in southern parts of the Kimberley, near the west Pilbara coast, the southern Gascoyne, and Goldfields, where daytime temperatures were up to 2 °C below normal (see October 2011 mean maximum temperature deciles & anomaly maps).

When averaged across the state, the maximum temperature during October 2011 for WA was close to normal. The Lower Southwest (southwest of a line from Jurien Bay to Bremer Bay) also experienced near average daytime temperatures during October 2011, however, mean maximum temperatures for the Lower Southwest in each month of 2011 have been above the long-term average (comparable records commenced in 1950). As a result, the mean maximum temperature for the Lower Southwest for the 2011 January to October period is the highest on record.

Minimum temperature

October 2011 mean minimum temperatures were above to very much above average over much of WA including the southern half of the state and extending to the western and southern Pilbara and central Interior. Very much above average minima were recorded across the SWLD, Eucla, and southern Interior, with some areas reporting up to 3 °C warmer than normal mean minima, and several sites across the SWLD recorded their highest October mean minimum temperature. Below to very much below average mean minima were confined to the north and west Kimberley, with areas of up to 2 °C cooler than normal mean minima reported (see October 2011 minimum temperature deciles & anomaly maps).

October 2011 was above average when looking at WA as a whole, whilst the Lower Southwest ranked as the 3rd warmest October on record in terms of mean minimum temperature. Comparable records commenced in 1950.

Other Phenomena

Severe thunderstorms developed in the Southeast Coastal district and neighbouring areas during the afternoon on the 12th and a farmer near Salmon Gums reported hail to appoximately 4cm diameter. Roof damage was reported in Kununurra on the 21st as the result of wind gusts from an afternoon storm, whilst large hail that smashed car windscreens was reported at Ellendale, also in the Kimberley, on the 22nd. Geraldton was impacted on the 26th as shops in the main street reported minor inundation as a result of heavy rainfall, whilst Sandstone in the Gascoyne received minor damage to buildings after hail and severe wind gusts passed through the region on the same day.

Details Extremes Records Summaries Important notes the top

Details Extremes Records Summaries Important notes the top