Monday, 2 November 2009 - Monthly Climate Summary for Tasmania - Product code IDCKGC17R0

Tasmania in October 2009: Cool at the start, warm at the end and drier than recent months

Tasmania's weather in October was mostly controlled by high pressure systems, resulting in few windy days and drier than usual conditions in all but the east. Most sites in the west received only half their usual October rain. There were several cold days and nights in the first two weeks, but the second half with warmer and temperatures climbed into the mid to high twenties on a few days. The last day of the month was the warmest at most sites.

An archive of previous monthly summaries for Tasmania is also available, as are summaries for other states and many other climate summaries and diagnostics.

Much drier than recent months

Because high pressure systems controlled the weather for most of the month, rainfall was below average except for a few parts of the east. Rain fell statewide with a complex area of low pressure that persisted near the state between the 12th and 15th, but most fronts that crossed the state were weak and had little effect. In the Midlands several sites received only around 25 mm - much less that the 100 mm or so of August and September. Only a few sites places over 100 mm, including Lake Margaret Power Station, Warra and Mount Barrow. Some sites in the west had their driest October on record or their driest October in around 30 years, and several had their driest month in nearly two years.

Several cold days, and no hot days until near the end

During the first two weeks of October nearly every day was cooler than usual in Tasmania. There were several days when southerly winds kept temperatures around five degrees below average, including on the 3rd, between the 6th and 9th, and in the north on the 13th. Mount Wellington had several days when it didn't rise much above 0°C, and on the 6th and 7th the temperature didn't exceed −1.2°C. The first warm to hot day was the 20th as northerly winds ahead of a weakening cold front pushed temperatures into the mid−20s at several sites. Some parts of the state were warm between the 27th and 29th, but the heat increased on the 30th and 31st as a north to northeast airflow and slow moving trough pushed temperatures higher. Strahan reached 27.5°C on the 30th, then Swansea, Scamander and Ouse all exceeded 30°C on the 31st. Some sites had their warmest October day in over 10 years. 

Overall, maximum temperature ranged from half a degree above average in the west to around a degree below average in the east. Orford and Swansea had their lowest October mean daily maximum temperature since 1976.

Many cold nights

Nearly every night until the 11th was cooler than usual due to a combination of light winds and cold airmasses. After that, several cloudy nights and warmer airmasses kept minima near or above average most of the time. Exceptions were the 25th and 26th, when temperatures plummeted as cloud cleared and winds dropped; Liawenee fell to −5.3°C on the morning of the 26th, the coldest temperature recorded in Tasmania during the month. Just a few nights later, the 30th and 31st were the warmest of the month, with overnight temperatures five of more degrees warmer than usual across the state. A number of sites didn't fall below 15°C, including Burnie and Orford which had their warmest October night on record.

Overall, there were more cool nights than warm ones so mean minima for the month were slightly below normal at most sites.

Further information

Ian Barnes-Keoghan
Meteorologist
Tasmania and Antarctica Climate Services Centre
Bureau of Meteorology
Phone (03) 6221 2043
Email climate.tas@bom.gov.au

Extremes

Hottest day
Highest temperature
30.9°C at Swansea Post Office on the 31st
Warmest days on average
Highest mean daily maximum temperature
18.0°C at Launceston (Ti Tree Bend)
Coolest days on average
Lowest mean daily maximum temperature
6.6°C at Mount Wellington
Coldest day
Lowest daily maximum temperature
−1.2°C at Mount Wellington on the 6th and 7th
Coldest night
Lowest temperature
−5.3°C at Liawenee on the 26th
Coolest nights on average
Lowest mean daily minimum temperature
−0.3°C at Mount Wellington
Warmest nights on average
Highest mean daily minimum temperature
10.1°C at Hogan Island
Warmest night
Highest daily minimum temperature
16.3°C at Orford (Aubin Court) on the 31st
Wettest overall
Highest total rainfall
 over 122 mm * at Lake Margaret Power Station
and Mount Read
Driest overall
Lowest total rainfall
17.8 mm at Flinders Island Airport
Wettest day
Highest daily rainfall
41.4 mm at Mount Barrow (South Barrow) on the 14th
Highest wind gust
126 km/h at Maatsuyker Island Lighthouse on the 20th

* Both Lake Margaret and Mount Read are missing some days during the month, but the available values sum to at least 122 mm.


Records

Record lowest total October rainfall
Total rainfall
for October 2009 (mm)
Previous lowest
for October
Years of
record
Average for
October
Savage River Mine 64.6 69.4 in 1969 42 169.6
Strathgordon Village 84.3 114.3 in 1972 42 251.0
Zeehan (West Coast Pioneers Museum) 74.2 88.1 in 1969 41 210.6
Lake St Clair National Park 73.5 85.0 in 2008 21 178.3

Lowest total October rainfall for at least 20 years
Total rainfall
for October 2009 (mm)
Most recent lower
for October
Years since
lower
Average for
October
Butlers Gorge 71.6 66.2 in 1969 30 160.0
Waratah (Mount Road) 61.8 42.7 in 1963 27 200.0



Lowest October mean daily maximum temperature for at least 20 years
Mean daily maximum
temperature
for October 2009 (°C)
Most recent lower
for October
Years since
lower
Average for
October
Orford (Aubin Court) 15.7 15.0 in 1976 33 17.4
Swansea Post Office 16.5 14.1 in 1976 33 17.8



Record highest October daily minimum temperature
Highest daily minimum
temperature
in October 2009 (°C)
Previous highest
for October
Years of
record
Average for
October
Burnie (Round Hill) 15.9 on the 31st 15.6 on the 30th in 1992 45 8.0
Orford (Aubin Court) 16.3 on the 31st 15.8 on the 1st in 1993 42 7.2



Summaries

In this table, key sites have been highlighted to make them easier to find. This table is very wide and may not fit if printed.


Summary statistics for October 2009
Maximum temperatures
for October
(°C)
Minimum temperatures
for October
(°C)
Rainfall
for October
(millimetres)
Mean for
October
2009
Diff
from
average
Highest for
October
2009
Mean for
October
2009
Diff
from
average
Lowest for
October
2009
Total for
October
2009
Average
for
October
Rank of
October
2009
Fraction of
October
average
Northern (district 91)
Bridport 16.0 −0.4 21.6 31st 7.2 −0.7 3.1 7th 46.5 59.5 average 78%
Burnie 16.8 +0.9 21.8 31st 8.6 +0.6 4.6 7th 38.0 85.5 low 44%
Cape Grim BAPS 14.7 +0.5 19.4 31st 9.1 −0.1 5.0 7th 35.2 60.1 low 59%
Cressy Research Station 16.8 −0.3 26.1 31st 4.9 −0.1 0.6 26th 41.0 49.3 average 83%
Devonport Airport 16.1 +0.4 21.2 23rd 6.8 −0.4 1.7 7th 34.2 64.5 low 53%
Launceston 18.0 0.0 26.4 31st 6.2 −0.7 0.9 10th 32.6 51.1 low 64%
Launceston Airport 16.9   26.4 31st 5.2   0.9 2nd 44.0
Low Head 15.4 +0.2 19.1 31st 9.0 −0.5 5.5 7th 33.4 52.6 average 63%
Luncheon Hill 15.6 +1.1 24.8 31st 5.7 −0.2 0.4 7th 66.2 131.4 low 50%
Marrawah 15.3 +0.4 21.3 31st 7.8 −0.3 3.5 7th 49.4 88.1 very low 56%
Scottsdale 16.1 −0.4 24.5 31st 5.6 −0.2 −0.1 2nd 49.6 84.0 low 59%
Sheffield School Farm 15.0 −0.1 22.2 31st 5.0 −0.7 −0.1 8th 57.0 78.0 average 73%
Smithton Aerodrome 16.7 +0.5 21.7 31st 6.3 −0.7 0.8 7th 31.4 78.8 very low 40%
Wynyard Airport 16.9 +1.0 22.7 31st 5.9 −0.2 0.6 3rd 44.0 98.0 very low 45%
East Coast (district 92)
Bicheno 16.2 −1.3 26.6 20th 8.3 −0.2 4.4 26th 68.6 56.0 high 123%
Eddystone Point 16.9 +0.6 21.2 31st 9.0 −0.1 4.2 2nd 58.0 69.3 average 84%
Fingal 16.4 −1.0 29.1 31st 5.0 +0.2 −0.6 2nd 41.8 54.8 average 76%
Friendly Beaches 17.0 −1.0 27.4 31st 8.0 −0.7 4.2 11th 29.0 62.2 low 47%
Lake Leake 12.9 −0.8 25.1 31st 2.8 −0.7 −2.4 26th 34.4 75.6 low 46%
Maria Island 15.3   24.1 31st 8.7   6.1 4th 36.4
Orford 15.7 −1.7 24.9 31st 7.4 +0.2 3.1 11th 58.8 60.0 average 98%
Scamander 16.2 −1.3 30.3 31st 8.0 0.0 3.4 3rd 36.9 62.6 average 59%
St Helens Aerodrome 16.5   29.7 31st 7.7   2.9 2nd 62.6
Swan Island 15.7   22.8 31st 9.5   6.1 8th 50.8
Swansea Post Office 16.5 −1.3 30.9 31st 6.3 −0.8 1.1 2nd 42.4 53.3 average 80%
Midlands (district 93)
Ross 16.2 −0.8 26.7 31st 4.5 −0.4 −1.6 26th 25.8 42.3 low 61%
Southeast (district 94)
Campania 16.5   24.5 20th 5.9   0.5 10th 42.4 41.4 average 102%
Cape Bruny 14.7 −0.5 20.2 20th 8.1 −0.2 4.2 10th 53.0 67.8 low 78%
Cape Bruny Lighthouse 13.9 −0.5 19.5 20th 8.1 +0.2 4.0 25th 67.6 83.6 average 81%
Dover 14.8 −1.4 21.1 20th 6.0 −0.5 0.5 4th 75.4 86.8 average 87%
Geeveston 16.0 −0.3 20.9 20th 6.1 +0.1 −0.6 4th 75.2 92.2 average 82%
Grove 16.1   25.7 30th 5.5   −1.0 4th 74.8
Hobart 16.3 −0.7 24.9 20th 7.6 −0.1 3.1 10th 62.4 61.8 average 101%
Hobart Airport 16.0 −1.3 25.2 20th 7.7 +0.2 3.2 4th 37.6 46.8 average 80%
Maatsuyker Island Lighthouse 12.9 −0.4 19.8 29th 7.8 +0.4 4.8 6th 62.0 106.2 very low 58%
Melton Mowbray 15.5 −1.1 27.1 31st 5.5 −0.1 0.0 26th 38.8 42.7 average 91%
Mount Wellington 6.6 −0.4 18.8 31st −0.3 −0.4 −4.7 10th 74.4 77.5 average 96%
Tasman Island 13.0   20.5 31st 7.3   4.3 7th 62.6
Tunnack Fire Station 13.6 −0.8 23.7 31st 4.2 −0.2 −1.7 26th 41.0 55.7 average 74%
Derwent Valley (district 95)
Bushy Park 17.2 −0.4 28.7 31st     −0.1 4th 38.0 57.4 low 66%
Maydena Post Office 15.6 0.0 26.9 31st 4.1 −0.7 −2.4 8th 53.5 122.7 very low 44%
Ouse Fire Station 17.6 0.0 30.1 31st 4.8 −0.6 −1.9 8th 24.0 54.7 very low 44%
Tarraleah Village 13.6 +0.1 25.6 31st 3.4 +0.2 −1.5 7th 51.9 111.1 very low 47%
Central Plateau (district 96)
Butlers Gorge 12.9 +0.5 24.4 31st 2.0 −0.4 −4.2 26th 71.6 160.0 very low 45%
Lake St Clair National Park 13.4 +0.8 24.9 31st 1.4 −0.6 −3.5 26th 73.5 178.3 lowest 41%
Liawenee 12.0   21.6 31st 0.3   −5.3 26th 30.2
West Coast (district 97)
Hartz Mountain 10.4 −0.3 22.8 30th 2.5 −0.1 −1.1 8th 98.6 93.1 average 106%
Mount Read 8.8 +1.4 19.3 31st     −3.0 8th
Scotts Peak Dam 15.3 +1.2 28.1 30th 4.9 −0.1 1.2 7th 84.6 168.5 very low 50%
Strahan Aerodrome 16.4 +0.4 27.5 30th 7.2 −0.1 1.0 7th 58.2 103.7 low 56%
Strathgordon Village 14.2 +0.7 23.5 30th 5.1 −0.3 −0.2 8th 84.3 251.0 lowest 34%
Warra 13.0   22.9 31st 4.2   −1.1 8th 116.4
King Island (district 98)
King Island Airport 15.9 +0.3 24.9 30th 8.6 −0.1 3.5 9th 49.0 74.3 low 66%
Flinders Island (district 99)
Flinders Island Airport 16.5 −0.2 27.5 31st 7.9 −0.7 2.1 4th 17.8 59.9 very low 30%
Hogan Island 15.8   26.3 31st 10.1   7.6 8th 23.2
Antarctica and Macquarie Island (district 300)
Macquarie Island 5.8 0.0 7.9 16th 1.9 −0.1 −0.9 28th 58.4 75.4 low 77%

Notes

This statement has been prepared based on information available at 9 am on Monday 2 November 2009. 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 decile ranking (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.

Further information

Ian Barnes-Keoghan
Meteorologist
Tasmania and Antarctica Climate Services Centre
Bureau of Meteorology
Phone (03) 6221 2043
Email climate.tas@bom.gov.au