Wednesday, 1 May 2013 - Monthly Climate Summary for Western Australia - Product code IDCKGC21R0
Rainfall during April 2013 was below to very much below average across large parts of the Southwest Land Division (SWLD), parts of the Gascoyne and in the central and eastern Interior. Above average rainfall was observed in the eastern Pilbara and in parts of the Kimberley, mainly due to heavy rainfall during the first few days of the month, while much of the remainder of the state saw near average rainfall for April 2013.
Averaged across the state as a whole, rainfall during April 2013 was close to average for WA. For the Lower Southwest (southwest of a line from Jurien Bay to Bremer Bay), and the SWLD, rainfall was below average. Comparable records commenced in 1910.
A weak tropical low moved westward to the north of the Kimberley from the 1st to 5th, resulting in showers and thunderstorms with moderate to heavy falls in parts of the Kimberley and east Pilbara. Particularly heavy rainfall totals were observed in the Kimberley in the 24 hours to 9am on the 3rd when a number of sites observed their wettest April day on record. Abney Hill observed the highest total of the month in WA with 127.0 mm, while Kingston Rest recorded 103.0 mm which is its wettest April day in 33 years of record. Wiluna in the far northern Goldfields also observed its wettest April day in 110 years of record with 98.2 mm.
A cloudband associated with ex-tropical cyclone Victoria brought moderate rainfall to southwest parts of the SWLD from the 11th to 13th, with daily totals generally in the 10 mm to 20 mm range. A band of middle level cloud moved across the southern half of WA on the 17th to 19th, bringing rain and isolated thunderstorms with some moderate falls mainly in the 10 mm to 35 mm range. A thunderstorm produced a heavy downpour at Mount William during the evening of the 17th with 16.0 mm recorded in the 10 minute period ending 2125 WST, which is considered an one in ten year event. The passage of a trough and cold fronts brought light to moderate rainfall to mainly southern WA from the 20th to 22nd.
A middle level trough combined with a surface trough in the Pilbara to produce showers and thunderstorms with some heavy falls in the region on the 26th and 27th. The heaviest daily rainfall total was recorded in the 24 hours to 9am on the 27th at Yarrie (Pilbara) with 95.0 mm, which was the third wettest April day on record at the site. In the south, showers with some moderate rainfall were observed in the South Coastal and Eucla as a cold front moved through southern WA.
Maximum temperatures during April 2013 were above to very much above average throughout much of WA, with areas of highest on record observed in western and southeastern parts of the state. A number of sites in the SWLD and Eucla observed their warmest April on record; while most of the southern half of WA was more than 3 °C warmer than normal, grading to up to 6 °C warmer than normal in inland parts. The only areas of the state to observe near average daytime temperatures during April 2013 were in the east Kimberley, east Pilbara and northwestern Northern Interior.
When averaged across the state as a whole, the mean maximum temperature for WA during April 2013 was very much above average and ranked as the 3rd warmest April since comparable records commenced in 1910. Similarly in the Lower Southwest (southwest of a line from Jurien Bay to Bremer Bay) daytime temperatures were very much above average, also ranking as the 3rd warmest April on record.
Warm to hot conditions were observed across much of western and southern WA to begin April 2013 with a trough near the west coast and a strong high in the Bight directing generally northeasterly winds over the area from the 1st to 5th. Conditions were particularly hot in the SWLD on the 3rd to 5th, with temperatures in the mid-to-high thirties. Jarrahwood in the Southwest observed a maximum temperature of 34.7 °C, which is its hottest day in April in 30 years of record. The trough moved eastward on the 5th and 6th, relieving temperatures in the southwest of the state, although maxima remained high over central and southeastern parts. The trough redeveloped near the west coast on the 7th and remained near stationary through to the 10th, with hot conditions returning to the SWLD, apart from the far southwest. A number of sites observed their hottest April day on record during this period with temperatures mainly in the mid-to-high thirties. The west coast trough gradually cleared eastward as a cloudband developed over southwest WA on the 11th, extending over much of the southern half of the state during subsequent days, with the hot conditions contracting to central and southeastern parts of the state. Maximum temperatures remained high in northern parts of the SWLD on the 11th, with Eneabba reaching 40.0 °C which is its new April record and the only 40 °C day of the month in the SWLD. The unseasonably hot start to the month was a major contributor to a number of sites across the SWLD and Eucla observing their warmest April on record.
Minimum temperatures during April 2013 were above to very much above average across southern and western WA with areas of up to 4 °C above normal in mainly inland southern parts. Areas of highest on record were observed through much of the SWLD, and in the southeastern Gascoyne, parts of the Goldfields, western Eucla with numerous sites, some with over 100 years of record, observing their warmest April on record. The record warm April in the SWLD was mainly a result of a very warm start to the month, combined with cloudy conditions through the middle of April and a general lack of frontal activity. Below average overnight temperatures were observed mainly in the north Kimberley, with an area of up to 2 °C below normal in the far northeast of the district, while the remainder of the state was near average.
When averaged across WA as a whole, the mean minimum temperature during April 2013 was very much above average, ranking as the 5th warmest on record, whilst the Lower Southwest (southwest of a line from Jurien Bay to Bremer Bay) ranked as the warmest April on record. Comparable temperature records commenced in 1910.
After hot day in the SWLD on the 10th, temperatures remained high overnight with daily minima in low twenties. Eneabba observed the highest minimum temperature in the SWLD with 23.6 °C on the 11th, which was the third hottest night in April on record at the site, while Badgingarra observed their warmest April night on record with 22.9 °C.
|Extremes in April 2013|
|Hottest day||42.6 °C at Roebourne on the 20th|
|Warmest days on average||37.7 °C at Roebourne|
|Coolest days on average||22.1 °C at Albany|
|Coldest day||14.7 °C at Ongerup on the 28th|
|Coldest night||2.8 °C at Eyre on the 1st|
|Coolest nights on average||11.8 °C at Collie East|
|Warmest nights on average|| 27.0 °C at Troughton
23.8 °C at Truscott
|Warmest night|| 28.8 °C at Troughton
Island on the 1st
28.4 °C at Broome Airport on the 1st
|Wettest overall||179.8 mm at Abney Hill|
|Wettest day||127.0 mm at Abney Hill on the 3rd|
|Highest wind gust||83 km/h at Roebourne Aero on the 26th|
|Record highest April daily rainfall|
Highest daily rainfall
in April 2013 (mm)
|Wiluna||68.2||on the 3rd||57.5||on the 9th in 2003||110|
|Lake Argyle Resort||64.4||on the 3rd||54.6||on the 29th in 1989||44|
|Kununurra Aero||73.6||on the 3rd||50.8||on the 29th in 2006||39|
|Kingston Rest||103.0||on the 3rd||61.0||on the 29th in 2006||33|
|Record highest April temperature|
in April 2013 (°C)
|Geraldton Airport Comparison||39.7||on the 11th||39.4||on the 6th in 1959||71||27.7|
|Perth Airport||37.7||on the 8th||= 37.7||on the 2nd in 1972||69||25.5|
|Corrigin||37.1||on the 10th||36.6||on the 6th in 1959||65||24.2|
|Pearce RAAF||39.4||on the 8th||38.6||on the 4th in 1972||56||26.3|
|Manjimup||34.4||on the 8th||33.6||on the 2nd in 1972||54||21.1|
|Dwellingup||34.7||on the 8th||34.4||on the 2nd in 1972||53||22.4|
|Merredin||38.0||on the 11th||36.5||on the 5th in 1998||48||25.4|
|Karnet||35.0||on the 8th||= 35.0||on the 2nd in 1972||47||23.2|
|Narembeen||37.6||on the 10th||36.7||on the 2nd in 1972||46||25.8|
|Eneabba||40.0||on the 11th||39.7||on the 1st in 1972||40||29.3|
|Hyden||38.2||on the 10th||37.4||on the 4th in 1978||40||25.6|
|Paynes Find||38.2||on the 10th||38.0||on the 7th in 1986||32||28.4|
|Jarrahwood||34.7||on the 3rd||34.6||on the 4th in 1991||30||23.7|
|Record highest April mean daily maximum temperature|
| Mean daily maximum
for April 2013 (°C)
| Previous warmest
|Perth Metro*||28.5||28.2||in 1999, 1987||116||25.8|
|Geraldton Airport Comparison||30.6||30.2||in 2011||70||27.7|
|Wongan Hills||29.5||28.8||in 1994||44||26.4|
|Record highest April daily minimum temperature|
Highest daily minimum
in April 2013 (°C)
|Bencubbin||22.2||on the 12th||= 22.2||on the 1st in 1989||55||12.8|
|Badgingarra Research Stn||22.9||on the 11th||22.8||on the 13th in 2009||45||13.5|
|Gascoyne Junction||27.9||on the 17th||26.5||on the 10th in 2011||41||18.6|
|Record highest April mean daily minimum temperature|
Mean daily minimum
for April 2013 (°C)
|Cape Leeuwin||17.8||17.1||in 1999||116||15.4|
|Cape Naturaliste||16.2||15.8||in 1937||109||13.9|
|Kalgoorlie-Boulder Airport||16.1||15.4||in 1945||72||12.6|
|Perth Airport||16.1||15.2||in 1978||68||12.9|
|Pearce RAAF||16.3||16.0||in 1978||51||13.3|
|Albany Airport Comparison||13.7||12.8||in 1965||48||11.6|
|Onslow Airport||23.5||23.3||in 2005||46||21.3|
|Badgingarra Research Stn||16.3||16.0||in 1994||44||13.5|
|Summary statistics for April 2013|
|North Kimberley (district 01)|
|Troughton Island||32.6||-0.1||33.9||19th||27.0||+0.2||24.3||5th||77.0||32.9||v high||234%|
|East Kimberley (district 02)|
|Argyle Aerodrome||35.0||+0.2||38.8||23rd||22.1||-0.7||17.7||29th||69.0||26.4||v high||261%|
|Halls Creek Airport||34.1||+0.3||38.5||23rd||20.7||+0.3||16.7||29th||8.4||21.4||average||39%|
|Kununurra Aero||35.2||0.0||38.1||23rd||20.0||-1.9||14.1||28th||120.0||30.4||v high||395%|
|West Kimberley (district 03)|
|Fitzroy Crossing Aero||36.7||+0.2||40.3||23rd||20.1||-0.6||12.7||29th||28.8||33.3||average||86%|
|De Grey (district 04)|
|Port Hedland Airport||36.5||+1.3||41.4||20th||21.7||+0.3||18.0||13th||0||22.1||lowest||0%|
|Fortescue (district 05)|
|Barrow Island Airport||32.4||+1.3||34.9||8th||25.3||+0.8||22.2||13th||0.2||41.8||low||0%|
|West Gascoyne (district 06)|
|Emu Creek Station||37.0||+2.1||41.9||15th||14.4||20.3||average||71%|
|Shark Bay Airport||33.0||+2.1||38.6||4th||19.8||+1.7||15.5||2nd||0.2||9.2||low||2%|
|East Gascoyne (district 07)|
|Murchison (district 07A)|
|Mount Magnet Aero||32.6||+3.9||37.3||6th||18.9||+2.8||9.6||22nd||1.4||20.5||low||7%|
|North Coast (district 08)|
|Geraldton Airport Comparison||30.6||+2.9||39.7||11th||17.0||+1.6||11.0||23rd||4.2||23.4||low||18%|
|Central Coast (district 09)|
|Badgingarra Research Stn||29.7||+2.5||37.2||8th||16.3||+2.8||9.3||21st||12.2||27.0||low||45%|
|Garden Island HSF||25.7||+1.9||35.7||8th||18.3||+2.5||13.6||29th||26.4||43.2||low||61%|
|Medina Research Centre||39.8||average||69%|
|South Coast (district 09A)|
|Albany Airport Comparison||22.5||+0.6||34.4||4th||13.7||+2.1||8.4||29th||0||60.1||lowest||0%|
|North Central (district 10)|
|South Central (district 10A)|
|Newdegate Research Station||26.3||+2.1||35.7||9th||12.9||+2.7||6.0||21st||4.8||26.2||low||18%|
|Eucla (district 11)|
|Red Rocks Point||25.0||37.6||12th||15.2||8.3||22nd||28.0|
|South East (district 12)|
|Leinster Aero||32.0||+4.3||36.1||19th||17.7||+2.3||9.3||22nd||0.4||26.8||v low||1%|
|Munglinup West||26.0||+1.8||36.5||9th||14.6||+2.6||7.9||21st||0||32.1||v low||0%|
|Salmon Gums Res.Stn.||26.3||+2.6||35.7||11th||12.3||+2.4||5.2||24th||9.8||27.1||low||36%|
|Southern Cross Airfield||29.3||+3.1||37.0||11th||14.7||+3.3||6.3||23rd||3.0||23.4||low||13%|
|North East (district 13)|
|Giles Meteorological Office||31.1||+1.7||36.8||20th||16.9||+0.4||12.7||24th||0||15.5||lowest||0%|
|Offshore Islands (district 200)|
|Christmas Island Aero||28.8||+0.6||29.4||19th||24.4||+0.9||22.2||15th||409.8||224.3||v high||183%|
|Cocos Island Airport||30.5||+0.8||31.3||15th||26.5||+1.3||24.5||9th||8.8||253.7||lowest||3%|
|Varanus Island||32.3||+1.2||34.1||14th||26.9||+0.9||24.3||27th||0||44.1||v low||0%|
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 Wednesday 1 May 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.