Monday, 3 September 2012 - Monthly Climate Summary for Tasmania - Product code IDCKGC27R0
Tasmania in August 2012: Only a few very cold days
Both temperatures and rainfall were generally close to average in Tasmania in August 2012. The main exceptions were the northeast (which was much drier than normal) and some of the northwest (which was wetter than normal). The most significant weather event of the month was on the 6th, when a deep low pressure system produced a record 20 m wave off Cape Sorell.
- Only a few very cold days
- Many cold nights
- Dry in the east
- Record 20 m wave at Cape Sorell
Only a few very cold days
Cool days were more common than mild days in August, but only a few of those days were especially cold. Even at Mount Wellington the temperature stayed below 1 °C on just 4 days, which is much less than the August average of 10 days. Most areas had their coldest day of the month on the 9th when the temperature generally remained below 12 °C. It was also cold on the 2nd and 6th, with ice and snow down to 300 metres on the 6th causing road closures across the south, west and Midlands areas. Another cold outbreak saw snow settle below 200 metres in the south on the morning of the 26th. Temperatures dropped again over the last few days of August, Mount Wellington only reaching a maximum temperature of -1.2 °C on the 31st, Tasmania's coldest August day this year.
There were only one or two mild days this August, in contrast with the many warm days experienced in the record-breaking August 2011. The 23rd was the warmest day, with temperatures approaching 20 °C at most locations. It was also the warmest day of winter: in Hobart the temperature reached 20.3 °C and Fingal 20.0 °C under sunny skies.
Overall, daytime temperatures were within a degree of average across Tasmania in August, but tending on the cool side at most sites.
Many cold nights, but none especially cold
Cold nights were frequent in the first half of August, whilst mild nights were more common in the latter half of the month. There were more cold nights this August than last, but some sites had a colder night in August 2011 than they did in August 2012. For example, the coldest night this August was -6.3 °C at Liawenee on the 13th, whereas last year the temperature at Liawenee dropped as low as -7.5 °C.
The mildest nights were on the 23rd and 28th when the temperature remained above 10 °C at many sites in the north and east: on the 23rd Friendly Beaches recorded a minimum of 11.9 °C (as did King Island on the 8th), Bicheno and Eddystone Point recorded a minimum of 11.5 °C.
Minimum temperatures were generally within one degree of average in August: just below average for most sites, but above average for several coastal sites. Overnight temperatures were generally cooler than 2011, but warmer than 2010.
Dry in the east
In contrast to the dry conditions in July, August rainfall was close to average across most of Tasmania. The exceptions were the northwest which was wetter than average, and the northeast which was drier than average. Most of the state's rain was delivered by cold fronts and low pressure systems.
The driest period was between the 10th and 14th when a ridge of high pressure extended across Tasmania, though even during this time some rainfall was still recorded in most areas.
Mount Read was the wettest location, receiving more than 399 mm of rain (the actual total is probably higher as some snow was not properly captured). By contrast, Scamander was the driest location with only 12 mm.
Record 20 m wave at Cape Sorell
A deep low pressure system passed to the south of Tasmania on the 5th and into the morning of the 6th, directing very strong winds across the Tasmanian region. A wind gust of 154 km/h was recorded at Maatsuyker Island that morning. The waverider buoy at Cape Sorell reported a wave height of 20.0 m at 4:27 am on the 6th. The wave was probably the result of two wave trains combining. This is a new record wave for Cape Sorell, eclipsing both the 18.68 m reported there in July 2011 and the 19.83 m reported from the old CSIRO buoy in July 1985.
Mild in Hobart
Maximum and minimum temperatures were above average in Hobart, but were not as as warm as August last year. The warmest day of the month was on the 23rd when the temperature reached 20.3 °C. The coldest days were on the 6th and the 9th when the temperature remained below 10 °C (although in a typical August, Hobart has 4 days below 10 °C).
Much of the first 3 weeks of August saw minimum temperatures below 6 °C in Hobart, but the coldest morning was the 26th when the temperature fell to 1.9 °C. An average August in Hobart sees 3 nights where the temperature drops below 2 °C.
Hobart received 58 mm of rain, just above the August average of 54 mm, and a few millimetres more than last year. Most of this rain was delivered with the passage of cold fronts. 15 mm of rain was recorded with a vigorous cold front on the 6th, the wettest day of the month.
Record warm at Macquarie Island
August 2012 was the warmest on record for Macquarie Island. It's mean maximum temperature of 6.3 °C beat the previous record of 6.2 °C set in 1980, and its mean minimum temperature of 3.5 °C beat the previous record of 3.2 °C set in 1971. The two combined to give an overall mean temperature of 4.9 °C, beating the previous mean temperature record of 4.6 °C set in 1989. The morning of the 9th was also record warm: the minimum of 6.3 °C equalling the highest minimum temperature record for August set on the 6th in 1985. Macquarie Island, while 1500 km southeast of Hobart, is actually part of Tasmania.
2012 so far
Both days and nights have been warmer than average this year so far, by up to one degree in most areas. There are a few exceptions: day-time temperatures have been slightly cooler than usual at a few sites in the Central Plateau and West Coast districts.
Rainfall has generally been close to average following a mix of dry and wet months this year so far, but some sites in the northwest, including Marrawah, Smithton and Wynyard, have had above average rain for the January to August period. A few sites in the northeast have had below average rainfall.
|Extremes in August 2012|
|Hottest day||20.3 °C at Hobart (Ellerslie Road) on the 23rd|
|Warmest days on average||14.8 °C at Bicheno (Council Depot)|
|Coolest days on average||3.0 °C at Mount Wellington|
|Coldest day||-1.2 °C at Mount Wellington on the 31st|
|Coldest night||-6.3 °C at Liawenee on the 13th|
|Coolest nights on average||-1.8 °C at Mount Wellington|
|Warmest nights on average||8.1 °C at Swan Island|
11.9 °C at King Island Airport on the 8th|
and at Friendly Beaches on the 23rd
|Warmest on average overall||10.8 °C at Swan Island|
|Coolest on average overall||0.6 °C at Mount Wellington|
|Wettest overall||399.2 mm at Mount Read *|
|Driest overall||11.9 mm at Scamander|
|Wettest day||40.2 mm at Lorinna on the 22nd|
|Highest wind gust||154 km/h at Maatsuyker Island Lighthouse on the 6th|
* The true total at Mount Read is probably higher, as it is likely some snow was lost.
Click on a map to show it full size in a pop-up window
|Summary statistics for August 2012|
|Northern (district 91)|
|Bridport (Sea View Villas)||13.7||0.0||17.0||23rd||5.4||-0.4||2.0||7th||88.4||87.7||average||101%|
|Burnie (Round Hill)||13.7||+0.6||17.5||11th||6.7||+0.6||1.8||31st||138.6||110.3||high||126%|
|Cape Grim BAPS (Comparison)||12.5||-0.3||14.7||23rd||7.6||-0.8||5.0||6th||139.8||93.4||high||150%|
|Cressy Research Station||12.6||-0.4||18.1||23rd||2.1||-0.5||-2.5||2nd||50.0||71.2||low||70%|
|Launceston (Ti Tree Bend)||13.8||0.0||19.6||23rd||3.4||-0.3||-1.6||2nd||70.4||86.4||average||81%|
|Luncheon Hill (Forestry)||10.7||-0.7||14.2||28th||4.4||-0.7||0.2||31st||263.4||206.5||high||128%|
|Scottsdale (West Minstone Road)||12.4||-0.2||17.7||23rd||3.8||-0.2||-1.4||7th||118.2||120.5||average||98%|
|Sheffield School Farm||11.5||-0.2||15.6||11th||2.9||-1.1||-1.2||2nd||159.6||133.0||average||120%|
|East Coast (district 92)|
|Bicheno (Council Depot)||14.8||+0.1||18.0||28th||6.6||+0.2||2.6||16th||19.4||51.1||low||38%|
|Fingal (Legge Street)||13.1||-0.2||20.0||23rd||1.4||+0.1||-4.6||7th||35.2||60.4||average||58%|
|Lake Leake (Elizabeth River)||9.1||-0.4||16.9||23rd||0.9||+0.1||-4.5||2nd||46.0||79.1||low||58%|
|Maria Island (Point Lesueur)||12.8||17.0||23rd||7.3||3.9||26th||40.2|
|Orford (Aubin Court)||13.7||-0.3||18.0||23rd||3.8||-0.5||-1.0||7th||37.4||62.1||average||60%|
|St Helens Aerodrome||14.3||0.0||18.4||23rd||4.9||-0.6||-0.1||7th||23.6||70.4||v low||34%|
|Swansea (Francis Street)||14.1||19.4||23rd||4.3||-0.1||7th||26.8|
|Midlands (district 93)|
|Ross (The Boulevards)||12.1||-0.5||17.7||23rd||2.1||-0.3||-2.8||31st||30.2||48.3||average||63%|
|Southeast (district 94)|
|Bull Bay (Lauriston)||13.2||-0.1||18.5||23rd||6.2||+0.2||2.0||26th||55.4||56.6||average||98%|
|Cape Bruny (Cape Bruny)||12.7||-0.2||18.9||23rd||6.5||-0.2||2.9||26th||73.2||90.2||low||81%|
|Cape Bruny Lighthouse||12.5||+0.6||18.3||23rd||7.0||+0.7||1.2||27th||81.8||93.0||average||88%|
|Dunalley (Stroud Point)||13.6||19.8||23rd||6.2||2.3||2nd||39.0|
|Geeveston (Cemetery Road)||12.9||-0.1||19.4||23rd||3.2||+0.2||-1.0||10th||111.8||104.3||average||107%|
|Grove (Research Station)||13.1||19.6||23rd||2.5||-1.9||10th||69.8|
|Hobart (Ellerslie Road)||13.8||+0.7||20.3||23rd||5.7||+0.5||1.9||26th||57.8||53.6||average||108%|
|Maatsuyker Island Lighthouse||11.0||-0.2||14.6||23rd||6.7||+0.2||3.2||26th||144.2||123.3||high||117%|
|Melton Mowbray (North Stockman)||12.2||-0.5||17.5||23rd||2.6||-0.2||-2.2||2nd||51.6||51.8||average||100%|
|Tunnack Fire Station||9.8||-0.9||15.6||23rd||1.6||-0.6||-4.0||2nd||66.2||66.2||average||100%|
|Derwent Valley (district 95)|
|Bushy Park (Bushy Park Estates)||13.7||+0.6||19.9||23rd||2.2||-0.2||-1.1||10th||40.8||54.0||average||76%|
|Maydena Post Office||11.6||-0.4||17.9||23rd||2.9||+0.3||0.4||10th||141.7||152.6||average||93%|
|Ouse Fire Station||13.3||-0.4||18.3||23rd||1.6||-0.6||-2.4||19th||44.2||62.1||average||71%|
|Central Plateau (district 96)|
|Lake St Clair National Park||7.7||-0.5||12.6||23rd||0.5||+0.2||-3.5||19th||214.6||246.1||average||87%|
|West Coast (district 97)|
|Hartz Mountain (Keoghs Pimple)||6.5||-0.2||13.0||23rd||0.8||-0.7||-2.8||26th|
|Low Rocky Point||12.5||14.7||23rd||6.8||3.9||13th||118.6||147.9||low||80%|
|Scotts Peak Dam||10.2||-0.2||18.8||23rd||3.4||-0.2||0.2||31st||231.4||212.3||average||109%|
|King Island (district 98)|
|King Island Airport||13.3||-0.4||16.4||28th||7.7||-0.1||2.5||1st||142.2||118.1||average||120%|
|Flinders Island (district 99)|
|Flinders Island Airport||13.8||0.0||19.8||23rd||5.9||-0.7||-0.8||2nd|
|Antarctica and Macquarie Island (district 300)|
* The true total at Mount Read is probably higher, as it is likely some snow was lost.
A Monthly Climate Summary is prepared to list the main features of the weather in Tasmania 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 8 am on Monday 3 September 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, 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.