Monday, 2 July 2012 - Monthly Climate Summary for Western Australia - Product code IDCKGC21R0
Rainfall during June 2012 was near average for much of WA. Above to very much above average rainfall was observed in the South Coastal district, Central West, eastern parts of the Central Wheat Belt, the southern Gascoyne and parts of the Goldfields. Most of the Southwest Land Division (SWLD) saw near average totals. In what is typically a dry time of year in the north of WA, areas of above average rainfall were observed in small parts of the Pilbara, particularly around the Karratha area, while large areas of below average rainfall were observed in the Kimberley and central Interior.
When averaged across the state as a whole, June 2012 rainfall was near average. The Lower Southwest (southwest a line from Jurien Bay to Bremer Bay) also observed near average rainfall during June 2012; however, for the year to date (January to June) rainfall has been below average, primarily due to a very dry autumn (the 7th driest). Comparable rainfall records commenced in 1900.
June 2012 saw frequent rainfall in western and southern parts of the SWLD, with some sites recording rainfall on over 20 days in the month. A series of low pressure systems and cold fronts brought a number of significant weather events to the SWLD, which not only brought moderate to heavy rainfall, but also damaging winds and significant storm surges during the first half of the month, particularly between the 7th and 13th. The second half of the month saw mainly light to moderate rainfall events in the SWLD, with the passage of several more moderate cold fronts.
A slow moving trough and low pressure system moved over the SWLD at the end of May and the start of June, bringing moderate to heavy rainfall and thunderstorms to southern and eastern parts of the SWLD and adjacent Goldfields. A number of locations in the Southwest and South Coastal districts registered daily rainfall totals over 80 mm during the first two days of June. Warner Glen in the Southwest district recorded a total of 106.4 mm on the 1st, which was its wettest day in its 63 years of record. Tamaru in the South Coastal received a daily total of 116.2 mm on the 2nd, which was the highest daily total for any month in its 47 years of record, and also the heaviest daily rainfall event in the SWLD since late last year when 125.6 mm was recorded at Williams in the Great Southern on 13 December 2011. Several sites in the South Coastal district recorded their highest June total rainfall with the combination of this event and above average rainfall for the remainder of the month.
A low off the WA west coast on the 6th brought extensive cloud to much of the state resulting in areas of rain over much of western WA. Heavy falls were observed in the Pilbara and Central West, with totals over 50 mm reported near Roebourne, whilst highest June daily falls in 10 years were reported at some Pilbara sites.
A rapidly deepening tropical low off the northwest coast moved near the west coast during the morning and crossed the Southwest district during the afternoon on the 10th. The system brought very windy conditions to the Lower West, Southwest, South Coastal, and Great Southern districts. The highest recorded wind gust during the event was 146 km/h at Cape Naturaliste, which is the strongest wind gust observed at the site in almost 10 years or record, and the 4th strongest wind gust on record in Western Australia in the May to August period. Widespread property damage was reported in western parts of the SWLD with a significant number of trees downed, and 800 power lines southwest of a line from Geraldton to Ravensthorpe damaged. More than 170,000 homes lost power and it took several days for power to be restored to all residents in the region. A significant storm surge with minor coastal inundation was reported along the SWLD west coast. Some moderate to heavy falls were observed in the west Pilbara, west Gascoyne, and western parts of the SWLD during the event and a few locations in the northern Central West recorded their wettest June day on record as the result.
Most of WA, apart from the Kimberley, experienced a wet day on the 11th as a cold front moved through the SWLD and a cloudband moved across northwest and central parts of the state. Moderate to heavy falls were mainly confined to southern parts of the SWLD, whilst the west coast parts of the division endured more severe winds and a storm surge event.
A rapidly developing cold front and deep low pressure system moved through the SWLD during the afternoon and evening of the 12th, and through central and eastern parts of southern WA on the 13th. Widespread rainfall was recorded through the SWLD, with heavy falls in the 40 mm to 60 mm range in the Southwest and Lower West districts. Thunderstorms, moderate to heavy rainfall, and severe wind gusts were reported in the SWLD, particularly in the Southwest and neighbouring districts, as further roof damage was reported to buildings, trees were uprooted, and additional power lines were downed. Another storm surge occurred although it was weaker than previous recent events.
Above average maximum temperatureswere observed in much of western, central and southeastern WA in June 2012 , with areas of up to 3 °C warmer than normal in the western Interior. Below average daytime temperatures were mainly confined to the east Kimberley where temperatures were up to 2 °C cooler than normal.
When averaged across the state as a whole, the mean maximum temperature for WA during June 2012 was near average, whilst for the Lower Southwest, daytime temperatures were also near average. The Lower Southwest has experienced a very warm first half of 2012. The mean maxima for the first six months (January to June ) was 0.9 °C above normal and ranked the 5th warmest January - June period on record, largely due to an above average January and a very warm autumn (the 5th warmest). Comparable temperature records commenced in 1950. This "warm" run of temperatures has persisted for almost three years as the Lower West has only recorded two below average months, in terms of maximum temperature, since September 2009.
A trough inland from the west coast and a high to the south of the state brought a very warm day to the eastern Central Wheat Belt on the 2nd, with a daily maxima in mid-twenties. Narembeen registered its warmest June day in 41 years of record, with a maximum temperature of 25.9 °C, exceeding the previous record of 25.4 °C set on 7 June 1988. Conversely, the coldest day of the month was the 13th when a deep low brought a cold airmass over the SWLD, with daily maxima barely over 10 °C in the southern parts of the SWLD. Snow fell on Bluff Knoll in the Stirling Ranges in the South Coastal district on the morning and early afternoon of the 13th.
June 2012 saw below to very much below average minimum temperatures in northern and eastern parts of WA, with overnight temperatures up to 5 °C cooler than normal in the far northeast Kimberley. Western parts of WA, from the west Pilbara to the South Coastal, reported above to very much above average mean minimum temperatures, with areas up to 2 °C warmer than normal in the southwest Gascoyne and much of Central West.
When averaged across the state as a whole, the June 2012 mean minimum temperature was near average, whilst the Lower Southwest observed above average overnight temperatures. Comparable records commenced in 1950.
Cloudy skies and northerly winds in the western parts of the state brought a warm night to the southwest Pilbara on the 10th, and western Central West on the 11th, with Emu Creek Station and Kalbarri observing their warmest June nights on record on the 10th and 11th respectively.
During the first half of 2012, WA as a whole has observed its 7th coolest January to June period on record in terms of minimum temperature, with each of the first six months this year seeing a cooler than normal minimum. In contrast, the Lower Southwest has observed its 8th warmest start to the year on record, with May being the only month to record a below average monthly minimum. In fact the warm conditions have persisted for almost two years in the Lower West as May 2012 has been the only below average month for the region since October 2010.
A trough off the west coast of the SWLD associated with a low southwest of the state produced severe thunderstorms over the Lower West and neighbouring districts in the late morning and early afternoon on the 7th. Tornadoes struck the suburbs of Dianella and Morley in Perth, and near York in the Central Wheat Belt, causing significant damage to homes and businesses as 5000 properties lost power. The tornadoes were the result of non-cold front related severe thunderstorms, which are highly unusual in southwest WA in winter.
|Extremes in June 2012|
|Hottest day||34.2 °C at Wyndham Aero on the 15th|
|Warmest days on average||30.7 °C at Kalumburu|
|Coolest days on average|| 15.8 °C at Bickley
15.8 °C at Katanning
|Coldest day|| 10.6 °C at Katanning
on the 13th
10.6 °C at Mount Barker on the 13th
|Coldest night||-4.0 °C at Eyre on the 15th|
|Coolest nights on average||4.1 °C at Eyre|
|Warmest nights on average||
21.9 °C at Troughton
|Warmest night|| 24.7 °C at Troughton
Island on the 3rd
22.3 °C at Port Hedland on the 11th
|Wettest overall||303.3 mm at Tamaru|
|Wettest day||116.2 mm at Tamaru on the 2nd|
|Highest wind gust||146 km/h at Cape Naturaliste on the 10th|
|Record highest June daily rainfall|
| Highest daily rainfall
in June 2012 (mm)
| Previous wettest
|Eradu||62.2||on the 10th||58.9||on the 28th in 1910||70|
|Warner Glen||106.4||on the 1st||91.2||on the 20th in 1967||63|
|Coolangatta||54.4||on the 10th||42.0||on the 14th in 1982||61|
|Tamar||85.2||on the 2nd||65.8||on the 14th in 1990||51|
|Albany Airport Comparison||96.4||on the 2nd||61.6||on the 25th in 2007||49|
|Tamaru||116.2||on the 2nd||36.1||on the 25th in 2007||47|
|Record highest total June rainfall|
| Total rainfall
for June 2012 (mm)
| Previous wettest
|Albany Airport Comparison||253.0||223.8||in 1978||48||108.0|
|Record highest June temperature|
in June 2012 (°C)
|Narembeen||25.9||on the 2nd||25.4||on the 7th in 1998||41||17.5|
|Record highest June daily minimum temperature|
Highest daily minimum
in June 2012 (°C)
|Emu Creek Station||22.2||on the 10th||21.3||on the 4th in 1991||41||12.6|
|Kalbarri||19.4||on the 11th||18.9||on the 28th in 2007||39||11.0|
|Summary statistics for June 2012|
|North Kimberley (district 01)|
|Wyndham Aero||30.3||-0.6||34.2||15th||13.7||-1.7||10.1||27th||0||3.8||v low||0%|
|East Kimberley (district 02)|
|Argyle Aerodrome||28.3||-0.8||33.6||15th||13.4||-2.5||9.1||25th||0||4.6||v low||0%|
|Halls Creek Airport||26.1||-1.1||31.3||15th||11.4||-2.2||7.8||21st||0||5.5||lowest||0%|
|West Kimberley (district 03)|
|Curtin Aero||30.1||-0.6||33.7||17th||14.4||-2.1||9.1||21st||0||8.4||v low||0%|
|Fitzroy Crossing Aero||29.6||-0.5||33.5||17th||10.5||-2.1||4.2||25th||0||7.9||v low||0%|
|West Roebuck||30.0||-0.5||33.2||17th||12.2||-0.4||3.6||25th||0||9.7||v low||0%|
|De Grey (district 04)|
|Port Hedland Airport||27.7||+0.1||30.9||17th||13.5||-0.6||8.6||23rd||11.2||20.7||average||54%|
|Roebourne Aero||27.1||-0.8||30.3||20th||13.0||-0.4||7.6||1st||83.0||23.4||v high||355%|
|Fortescue (district 05)|
|Barrow Island Airport||24.0||-0.3||27.4||10th||18.8||+0.2||15.1||27th||33.4||25.3||high||132%|
|West Gascoyne (district 06)|
|Emu Creek Station||26.6||+0.6||30.0||12th||13.1||+0.5||7.7||3rd||24.1||36.8||average||65%|
|Shark Bay Airport||24.1||+0.2||29.8||3rd||13.2||+1.4||8.8||18th||90.6||44.1||high||205%|
|East Gascoyne (district 07)|
|Murchison (district 07A)|
|Mount Magnet Aero||19.7||-0.2||25.0||2nd||9.3||+1.1||1.9||22nd||48.8||21.1||high||231%|
|North Coast (district 08)|
|Geraldton Airport Comparison||21.4||+0.5||28.7||4th||12.3||+1.3||6.2||22nd||113.4||99.4||average||114%|
|Morawa Airport||19.9||-0.2||26.0||2nd||9.7||+2.3||3.8||30th||97.2||41.5||v high||234%|
|Central Coast (district 09)|
|Badgingarra Research Stn||19.0||+0.3||25.8||3rd||9.8||+1.4||4.7||21st||113.2||104.0||average||109%|
|Garden Island HSF||18.9||-0.2||23.1||3rd||12.8||+0.7||7.7||22nd||139.6||121.8||high||115%|
|Medina Research Centre||19.5||+0.2||24.3||3rd||10.3||+1.3||2.1||22nd||153.2||148.3||average||103%|
|South Coast (district 09A)|
|Albany Airport Comparison||16.9||+0.3||20.7||9th||8.8||+0.7||3.2||25th||253.0||108.0||highest||234%|
|Rocky Gully||15.9||+0.4||20.1||3rd||8.1||+0.5||1.5||21st||150.8||90.3||v high||167%|
|North Central (district 10)|
|South Central (district 10A)|
|Lake Grace Comparison||17.0||+0.5||23.9||2nd||7.4||+0.7||1.8||23rd||33.4||50.6||low||66%|
|Newdegate Research Station||17.2||+0.6||24.0||2nd||5.4||+0.3||0.0||23rd|
|Eucla (district 11)|
|Red Rocks Point||18.5||24.8||19th||8.4||1.3||15th||33.4|
|South East (district 12)|
|Salmon Gums Res.Stn.||17.5||+0.6||23.9||1st||5.7||0.0||-0.6||25th||38.2||38.3||average||100%|
|Southern Cross Airfield||17.9||0.0||23.7||2nd||6.3||+1.9||-0.2||23rd||54.2||28.6||high||190%|
|North East (district 13)|
|Giles Meteorological Office||19.9||-0.4||25.6||13th||6.2||-1.9||0.0||23rd||1.4||17.3||average||8%|
|Offshore Islands (district 200)|
|Christmas Island Aero||27.0||0.0||28.6||1st||23.6||+0.4||20.8||10th||83.2||153.9||average||54%|
|Cocos Island Airport||29.0||+0.5||30.0||23rd||24.8||+0.3||22.7||9th||219.6||211.8||average||104%|
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 Monday 2 July 2012. 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.
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.
Records in this summary are based on sites with at least 30 years of data.