Thursday, 1 August 2013 - Monthly Climate Summary for Western Australia - Product code IDCKGC11R0
Rainfall in July 2013 was below to very much below average over the western and southern Gascoyne, central Goldfields, and much of the Southwest Land Division (SWLD). Pockets of above to very much above average rainfall were observed in the Great Southern, western Southeast Coastal, southern Goldfields, and Eucla, largely as a result of a significant rainfall event that moved through these areas from the 11th to 13th. Little if any rainfall was reported across much of the Pilbara, Kimberley, and northern Interior during July 2013, and although large parts of the Pilbara and west Kimberley reported below to very much below average rainfall, it is typically a dry month in the north. The remainder of the State saw near average rainfall.
For WA as a whole, as well as for the Lower Southwest (southwest of a line from Jurien Bay to Bremer Bay) and the SWLD, rainfall during July 2013 was below average. As a result of June being extremely dry in the SWLD, the June-July period for both the Lower Southwest and SWLD was the fourth driest since comparable records commenced in 1900. Only 1976, 2006 and 2001 were drier in the Lower West, whilst for the SWLD as a whole, only 1976, 2006, and 1977 were drier.
A number of weak cold fronts and subsequent onshore flow produced mainly light rainfall in the SWLD and Eucla between the 2nd and the 7th, with some moderate falls near the SWLD south coast, while a weak trough over central parts of the State produced areas of rain in the northern Goldfields on the 7th. A cold front and associated cloudband moved through southern WA on the 9th and 10th, bringing widespread rainfall to the SWLD and southern Goldfields with moderate falls in the Lowest West and adjacent Southwest district. A complex low pressure system moved across the southern half of the State into the Bight between the 11th and 13th bringing widespread significant rainfall to the SWLD and adjacent Gascoyne and Goldfields. A number of sites in the Central Wheat Belt, Great Southern, and South and Southeast Coastal recorded their wettest July day on record during the event, including Tamaru in the South Coastal which recorded 99.3 mm in the 24 hours to 9am on the 13th, its wettest July day in 48 years of record. A slow moving cold front moved through the SWLD on the 15th bring widespread showers to the region and heavy falls of 60 mm to 100 mm were reported in the Margaret River region of the Southwest district with some localised flooding. A daily total of 99.4 mm at Witchcliffe on the 15th was the highest daily rainfall of the month in the State. A strong cold front moved through the SWLD, Gascoyne, Goldfields, and Eucla on the 16th and 17th, bringing widespread rainfall to these regions, with thunderstorms and damaging winds reported in the SWLD. A strong cold front and cloudband moved across western and southern WA on the 24th to produce widespread rainfall in the southern Gascoyne and SWLD, with moderate to heavy falls in the Southwest and Lower West districts. Wokalup in the Southwest recorded 63.6 mm in the 24 hours to 9am on the 24th, its highest July daily fall in 62 years of record. Another strong cold front and cloudband moved across the southern half of WA on the 26th and 27th producing widespread rainfall with moderate falls, particularly in the Lower West. A weak cold front brushed through the southwest corner overnight on the 31st bringing generally light showers to much of the SWLD with moderate falls observed in the Southwest and Lower West.
Above to very much above average mean maximum temperatures were observed in the Kimberley and adjacent Northern Interior, the southern Pilbara, west Gascoyne, SWLD, eastern Eucla, and eastern Southern Interior, with areas up to 3 °C warmer than normal in the eastern Eucla. Much of the Pilbara, east Gascoyne, Goldfields, Southern Interior, and Southeast Coastal saw near average temperatures.
Averaged across the state as a whole, the mean maximum temperature for WA in July 2013 was above average. For the Lower Southwest (southwest of a line from Jurien Bay to Bremer Bay) the mean maximum temperature was also above average.
The first week or so of July 2013 saw varying cool to warm conditions across the State, but from the 9th to 16th warmer than normal conditions dominated most regions. Relatively cool conditions were most common from the 17th to 21st, but from the 23rd to the end of the month, mostly warmer than normal conditions prevailed. Wet and cloudy conditions resulted in a cold day in the Goldfields and southern Gascoyne on the 7th, and Yeelirrie in the Goldfields recorded the lowest maximum temperature of the month in the State with 9.3 °C on the 7th, its second coldest July day in 39 years of record, only behind a maximum of 9.0 °C on 13 July 2004. Light winds and a warming airmass in the north saw consecutive hot days in the Kimberley on the 14th and 15th with daily maxima over 35.0 °C at a number of sites. Curtin Aerodrome in the west Kimberley observed the highest maximum temperature of the month in the State with 36.5 °C on the 14th, which was the second hottest July day in 21 years of record at the site, only behind 36.7 °C on 30 July 1992. A cold day was observed in much of the SWLD on the 17th as cold southerly winds and wet conditions swept across the region. Both Manjimup and Mount Barker recorded a daily maximum temperature of 9.6 °C.
A broad area extending from the Pilbara, through the adjacent Northern Interior, Southern Interior, eastern Goldfields, and Eucla, saw above to very much above average mean minimum temperatures in July 2013, as did parts of the east Kimberley. Means up to 3 °C warmer than normal were recorded in the inland southern Pilbara and far northern Gascoyne, as well as in the far east Kimberley. In contrast, below to very much below average mean minimum temperatures occurred in the southwest Gascoyne and much of the northern and central SWLD, with means up to 2 °C cooler than normal reported in these regions.
Averaged across the state as a whole, the mean minimum temperature for WA in July 2013 was near average, while averaged across the Lower Southwest (southwest of a line from Jurien Bay to Bremer Bay) the mean minimum temperature was also near average.
Varying conditions, in terms of minimum temperatures, were reported across the State during the beginning of July but from the 10th to 17th predominantly warmer than normal conditions prevailed, before returning to more variable conditions for the remainder of the month. Persistent fresh northwesterly winds and above average sea surface temperatures resulted in a record high minimum temperature at Cape Leeuwin on the 1st. A minimum of 17.7 °C was the highest minimum during July in 106 years of record, easily exceeding the previous record of 16.7 °C on 5 July 1913. In contrast, cold nights were reported across southern WA from the 5th to the 9th as a result of generally clear skies and light winds. Many sub-zero temperatures were reported, aided by particularly dry soils following an extremely dry June, and a number of sites in the SWLD experienced their coldest or equal coldest night in July on record on the 8th. Wandering in the Great Southern recorded a minimum of -4.8 °C on the 8th, the lowest temperature recorded in WA in July 2013. Cloudy skies and northwesterly winds on the 15th kept temperatures unusually mild overnight in southwest WA with stations in the Southwest and South Coastal districts breaking their highest minimum temperature on record for July. Cold nights were again observed in western parts of the State between the 18th and 22nd as Lancelin in the Lower West recorded a temperature of 1.5 °C on the 21st, its equal lowest temperature in 49 years of record, equal with a minimum of 1.5 °C on 25 July 1979.
A series of cold fronts moved through the SWLD between the 15th and 17th, bringing heavy rainfall and damaging winds to southern districts. Flash flooding was reported in the Southwest as rainfall totals in the 60 mm to 100 mm range were reported on the morning of the 15th and a river crossing was washed away as a result. Severe wind gusts of 100 km/h to 115 km/h were recorded at coastal sites in the Lower West, Southwest, and Southeast Coastal on the 16th and 17th, resulting in more than 6000 homes in the Perth metropolitan area and southwest WA without power. The WA Department of Fire and Emergency Services (DFES) received more than 138 calls for assistance.
Numerous damaging wind gusts (between 90 km/h and 102 km/h) were recorded across southern WA as a strong cut off low and associated cold front passed over the region from the 25th to the 27th. DFES received a total 53 calls for help during this period, with damage reported in the Mandurah suburbs of Halls Head and Silver Sands, as well as in Kalgoorlie, Moora, and York. In the Perth metropolitan area, 22 calls for assistance were received overnight on the 26th and on the morning of the 27th with damage occurring in the northern suburbs of Heathridge and Beldon.
|Extremes in July 2013|
|Hottest day||36.5 °C at Curtin Aero on the 14th|
|Warmest days on average||32.8 °C at Wyndham Aero|
|Coolest days on average||14.9 °C at Katanning|
|Coldest day||9.3 °C at Yeelirrie on the 7th|
|Coldest night||-4.8 °C at Wandering on the 8th|
|Coolest nights on average||2.4 °C at York|
|Warmest nights on average|| 23.4 °C at Troughton
19.2 °C at Truscott
|Warmest night|| 25.2 °C at Troughton
Island on the 23rd
24.5 °C at Wyndham on the 8th
|Wettest overall||275.0 mm at Mount William|
|Wettest day||99.4 mm at Witchcliffe on the 15th|
|Highest wind gust||115 km/h at Cape Naturaliste on the 16th|
|Record highest July daily rainfall|
| Highest daily rainfall
in July 2013 (mm)
| Previous wettest
|Corrigin||62.5||on the 12th||45.6||on the 30th in 2001||104|
|Colorado||61.0||on the 12th||46.0||on the 8th in 1930||101|
|Koorikin||59.4||on the 12th||45.2||on the 30th in 2001||101|
|Ardath||57.0||on the 12th||50.0||on the 12th in 1990||96|
|Kondinin||71.0||on the 12th||45.6||on the 30th in 2001||96|
|Narembeen||38.6||on the 12th||31.0||on the 15th in 1978||87|
|Warner Glen||78.0||on the 15th||76.2||on the 3rd in 1955||64|
|Wokalup||63.6||on the 24th||52.3||on the 26th in 1960||62|
|Mount Walker||47.0||on the 12th||31.2||on the 5th in 1963||55|
|Tamaru||99.3||on the 13th||94.5||on the 20th in 1991||48|
|Record highest July daily minimum temperature|
Highest daily minimum
in July 2013 (°C)
|Cape Leeuwin||17.7||on the 1st||16.7||on the 5th in 1913||107||11.3|
|Manjimup||13.6||on the 15th||13.3||on the 20th in 1959||54||6.4|
|Albany Airport Comparison||13.6||on the 15th||13.4||on the 1st in 1985||49||7.5|
|Jarrahwood||15.0||on the 15th||14.0||on the 30th in 2007||31||4.8|
|Record lowest July temperature|
in July 2013 (°C)
|Northam||-3.2||on the 8th||= -3.2||on the 12th in 1997||105||5.4|
|Kellerberrin||-4.5||on the 8th||-3.5||on the 12th in 2005||102||5.6|
|Narrogin||-2.7||on the 8th||= -2.7||on the 1st in 1920||94||5.2|
|Salmon Gums Res.Stn.||-4.4||on the 8th||= -4.4||on the 4th in 1962||76||4.6|
|Corrigin||-4.2||on the 8th||-3.8||on the 20th in 1987||66||4.9|
|Lancelin||1.5||on the 21st||= 1.5||on the 25th in 1979||46||9.9|
|Beverley||-3.8||on the 8th||-2.6||on the 19th in 2012||44||5.1|
|Summary statistics for July 2013|
|North Kimberley (district 01)|
|Troughton Island||29.3||+1.2||31.3||9th||23.4||+1.3||19.6||27th||0||2.7||v low||0%|
|East Kimberley (district 02)|
|Argyle Aerodrome||30.9||+1.3||34.7||15th||16.7||+1.1||10.0||25th||0||1.3||v low||0%|
|Halls Creek Airport||28.4||+1.2||33.2||15th||14.0||+1.4||6.8||27th||0.2||6.0||average||3%|
|West Kimberley (district 03)|
|Broome NTC AWS||27.3||31.3||15th||18.9||15.1||26th|
|Curtin Aero||32.0||+1.1||36.5||14th||15.7||+0.4||9.9||27th||0||7.5||v low||0%|
|Fitzroy Crossing Aero||31.4||+0.7||35.8||15th||12.1||0.0||4.8||25th||0||6.3||v low||0%|
|West Roebuck||30.1||-0.8||34.0||14th||13.6||+1.2||8.2||25th||0||18.2||v low||0%|
|De Grey (district 04)|
|Marble Bar||27.1||-0.1||31.7||16th||12.2||+0.1||7.4||26th||0||17.8||v low||0%|
|Port Hedland Airport||27.5||+0.4||31.5||16th||13.2||+0.9||8.4||21st||0||11.0||lowest||0%|
|Fortescue (district 05)|
|Barrow Island Airport||23.2||-0.5||25.4||16th||17.3||-0.2||13.3||21st||0.2||12.8||low||2%|
|West Gascoyne (district 06)|
|Carnarvon Airport||23.2||+0.9||28.6||23rd||9.9||-1.0||4.0||22nd||0.2||44.7||v low||0%|
|Emu Creek Station||25.8||+0.3||30.1||14th||11.3||0.0||7.5||21st||0.1||21.5||low||0%|
|Shark Bay Airport||22.7||0.0||26.0||23rd||10.0||-0.5||4.3||22nd||10.2||28.9||low||35%|
|East Gascoyne (district 07)|
|Murchison (district 07A)|
|Mount Magnet Aero||19.6||+0.9||27.9||15th||7.0||0.0||0.3||18th||8.6||31.2||low||28%|
|North Coast (district 08)|
|Central Coast (district 09)|
|Badgingarra Research Stn||17.7||+0.1||21.4||23rd||6.2||-1.0||3.2||12th||83.6||104.2||average||80%|
|Garden Island HSF||17.9||+0.1||21.8||23rd||11.0||0.0||6.5||8th||120.0||114.9||average||104%|
|Medina Research Centre||18.9||+0.6||22.7||23rd||6.9||-1.3||0.8||18th||113.6||146.8||low||77%|
|South Coast (district 09A)|
|North Central (district 10)|
|South Central (district 10A)|
|Newdegate Research Station||15.3||+0.1||20.2||23rd||3.4||-0.6||-3.8||8th||38.4||47.5||average||81%|
|Eucla (district 11)|
|Red Rocks Point||19.0||26.6||16th||8.0||4.1||8th||70.2||41.1||v high||171%|
|South East (district 12)|
|Norseman Aero||16.7||-0.6||22.1||9th||3.7||-0.3||-3.9||8th||55.2||22.5||v high||245%|
|Salmon Gums Res.Stn.||16.4||+0.3||21.4||15th||4.5||-0.1||-4.4||8th||44.4||37.0||high||120%|
|Southern Cross Airfield||17.4||+0.8||24.4||15th||2.8||-0.6||-2.9||6th||20.4||33.7||low||61%|
|North East (district 13)|
|Giles Meteorological Office||20.7||+0.7||27.3||12th||6.7||-0.1||2.1||20th||2.0||11.5||average||17%|
A Monthly Climate Summary is prepared to list the main features of the weather in Western Australia using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.
This statement has been prepared based on information available at 10 am on Thursday 1 August 2013. Some checks have been made on the data, but it is possible that results will change as new information becomes available.
Averages are long-term means based on observations from
all available years of record, which vary widely from site to site.
They are not shown for sites with less than 10 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of long-term average rain.
The Rank indicates how rainfall this time compares with the climate record for the site,
based on the
(very low rainfall is in decile 1, low in decile 2 or 3,
average in decile 4 to 7, high in decile 8 or 9
and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a percentage of the long-term mean.
The ACORN-SAT dataset is being used for temperature area averages from December 2012 onwards. The major change from earlier datasets is that the ACORN-SAT dataset commences in 1910, rather than 1950, and hence rankings are calculated using a larger set of years.