Thursday, 1 October 2009 - Monthly Climate Summary for Tasmania - Product code IDCKGC17R0

Tasmania in September 2009: another wet month

  • Wettest September on record at some eastern sites
  • Temperatures mostly above average
  • Floods and damaging winds
  • A wet year so far

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

Another wet month

September was another wet month in Tasmania after a number of low pressure systems passed close to the state. It was the wettest September on record at some sites in the east, the southeast and the southern Midlands. Two that stand out are Oatlands where 116.8 mm was the wettest September in 122 years of record, and Bicheno where 180.2 mm while not quite a record was more than four times normal September rain. For many others (including Hobart) it was the second-wettest September on record or the wettest for many decades. Even the driest locations (Ouse and Hummocky Hills) had over 60 mm. Areas of the north and the southwest had near-normal rainfall for the month.
The wettest days were the 8th, 22−23rd and 27th. To 9 am on the 23rd a total of 122 mm fell at Gray (near St Marys in the northeast), which was the highest daily total for the month. Totals also exceeded 50 mm at a number of sites along or near the east coast on this day and a number had their highest September daily rainfall on record, including Eddystone Point and Bagdad.

A wet year so far

The rain of September, when added to that of the very wet August, a July that was wet in many areas, a June that was very wet in the east, and more rain scattered through the year has led to one of the wettest January-to-September periods for many decades, especially in the southeast.

An example is Hobart, where the total of 133.8 mm is the second-wettest September on record there (although well behind the record 202 mm in 1957). Hobart has had 672.6 mm in the nine months from January to September, which is the third-wettest on record (behind 713 mm in 1956 and 820 mm in 1946). This total is also above the average annual rain of 615 mm (over the period 1882 to 2008), and well beyond the 275 mm recorded in the nine months from January to September 2008. A table of some other records for the 9 month period appears below.

Some warm days, some cool days

There were several periods of cool weather, especially in the east and southeast when it was overcast and raining (such as the 9th, 22nd and 27th) or in the wake of cold fronts (such as the 1st and 14th). The warmest weather was on the 12th, when temperatures into the low 20s were reported in the east in northerly winds ahead of a cold front; Flinders Island Airport and Hogan Island (in northern Bass Strait) almost reached 25°C. The north of the state saw some more warm weather on the 28th, and for much of the south and west the warmest day was the 30th.

Overall, maximum daytime temperatures were mostly about half a degree warmer than usual for September, except in the inland east where they were cooler than usual by a similar amount.

Night temperatures mostly above average

Mild nights were much more common than cold ones right through the month. There were several sub-zero temperatures reported at some sites in the first few days, again on the 11th, and on the 29th, but these were more than balanced by several nights with temperatures staying in double digits. The night of the 12th and morning of the 13th were especially mild for the time of year, with overnight minimum temperatures in most areas kept high by strong winds as a cold front crossed. Bicheno had its warmest September night on record to 9am on the 13th, with the temperature there not dropping below 15.8 °C. The morning of the 17th was also very mild.

Overall, minimum temperatures were above average by around a degree, somewhat more in the inland northeast. Many sites had their warmest September nights since 2001.

Floods and damaging winds

The weather brought considerable damage across the state during the month. With sodden soils developing over previous months, the rain caused dramatic rises in streams and rivers. Moderate flooding was reported in many eastern and southern rivers through the month. A deep low pressure system close to the state on the 27th brought strong to gale force southerly winds and caused widespread damage. Two things that may have exacerbated the amount of damage were that the direction was unusual for such strong winds, and the wet ground had loosened some tree roots.

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
24.7°C at Flinders Island Airport and Hogan Island on the 12th
Warmest days on average
Highest mean daily maximum temperature
16.5°C at Scamander
Coolest days on average
Lowest mean daily maximum temperature
5.2°C at Mount Wellington
Coldest day
Lowest daily maximum temperature
0.2°C at Mount Wellington on the 1st
Coldest night
Lowest temperature
−5.7°C at Liawenee on the 29th
Coolest nights on average
Lowest mean daily minimum temperature
−1.1°C at Mount Wellington
Warmest nights on average
Highest mean daily minimum temperature
9.7°C at Hogan Island
Warmest night
Highest daily minimum temperature
15.8°C at Bicheno (Council Depot) on the 13th
Wettest overall
Highest total rainfall
298.8 mm at Lake Margaret Power Station
Driest overall
Lowest total rainfall
61.8 mm at Hummocky Hills
Wettest day
Highest daily rainfall
122.6 mm at Gray (Dalmayne Rd) on the 23rd
Highest wind gust
146 km/h at Maatsuyker Island Lighthouse on the 27th

Records

Record highest September daily rainfall
Highest daily rainfall
in September 2009 (mm)
Previous highest
for September
Years of
record
Eddystone Point 85.8 on the 23rd 73.6 on the 6th in 1983 102
Bagdad Post Office 44.0 on the 23rd 38.4 on the 15th in 1957 86
Mount Wellington 73.8 on the 23rd 50.0 on the 13th in 1999 29
Nugent (Twilight Valley) 88.4 on the 23rd 72.2 on the 12th in 2005 27
Scamander 90.0 on the 23rd 50.6 on the 22nd in 1984 26
Richmond (Strathayr) 27.4 on the 27th 19.0 on the 20th in 1996 21



Record highest total September rainfall
Total rainfall
for September 2009 (mm)
Previous highest
for September
Years of
record
Average for
September
Oatlands Post Office 116.8 110.8 in 1966 122 42.9
Levendale 210.0 126.4 in 1984 64 59.4
Orford (Aubin Court) 170.4 162.9 in 1960 57 52.2
Tooms Lake (Tooms River) 160.4 135.0 in 1984 47 49.5
Huonville (Tutton Avenue) 180.6 160.4 in 2003 39 79.2
Risdon Vale (Poplar Road) 120.4 92.0 in 2005 31 45.7
Nugent (Twilight Valley) 245.6 152.1 in 1984 27 74.0
Mount Wellington 225.4 188.0 in 1997 24 72.0
Tea Tree (The Point) 132.8 87.4 in 2005 24 48.1

Highest total September rainfall for at least 20 years
Total rainfall
for September 2009 (mm)
Most recent higher
for September
Years since
higher
Average for
September
Eddystone Point 158.4 173.3 in 1916 93 63.7
Hobart (Ellerslie Road) 133.8 201.6 in 1957 52 53.2
Swansea Post Office 151.0 161.6 in 1960 49 41.1
Lewis Hill (St Pauls River) 154.2 202.0 in 1966 43 52.0
Bicheno (Council Depot) 180.2 186.5 in 1959 42 44.7
Fort Direction 92.2 96.8 in 1966 36 40.7
Blackmans Bay Treatment Plant 126.4 130.8 in 1983 25 57.0
Fingal (Legge Street) 129.2 139.4 in 1984 25 49.7
Grove (Comparison) 169.0 174.6 in 1983 25 74.7
Lake Leake (Elizabeth River) 175.0 188.7 in 1984 25 71.2
Rotherwood 125.6 140.8 in 1984 25 56.3
York Plains (Handroyd) 104.2 126.9 in 1984 25 44.4
Copping 138.0 139.0 in 1983 24 62.2
Taroona (Taroona Crescent) 121.8 137.0 in 1983 23 54.0


Record highest September daily minimum temperature
Highest daily minimum
temperature
in September 2009 (°C)
Previous highest
for September
Years of
record
Average for
September
Bicheno (Council Depot) 15.8 on the 13th 15.5 on the 29th in 1998 35 7.3



Records for the 9 months from January to September


Record highest total January to September rainfall
Total rainfall
for January to September 2009 (mm)
Previous highest
for January to September
Years of
record
Average for
January to September
Grove (Comparison) 836.2 808.0 in 1996 56 548.0
Copping 868.0 815.5 in 1996 40 570.7
Rotherwood 625.0 573.4 in 2003 37 421.3
Geeveston (Cemetery Road) 978.8 873.1 in 1996 34 651.7
Zeehan (West Coast Pioneers Museum) 2289.4 2253.4 in 1980 34 1854.0
Risdon Vale (Poplar Road) 639.2 621.6 in 1996 27 399.5
Nugent (Twilight Valley) 1143.0 924.6 in 1996 25 609.2
Blackmans Bay Treatment Plant 673.8 651.6 in 1996 21 447.1
Campbell Town (Elizabeth R) 522.2 491.8 in 1970 21 371.1
Cape Grim BAPS 797.0 775.4 in 1988 21 603.5

Highest total January to September rainfall for at least 20 years
Total rainfall
for January to September 2009 (mm)
Most recent higher
for January to September
Years since
higher
Average for
January to September
Dover 896.0 1186.2 in 1946 56 646.5
Hobart (Ellerslie Road) 672.6 713.2 in 1956 53 444.2
Hobart Airport 528.6 584.3 in 1960 49 355.1
Oatlands Post Office 589.6 648.5 in 1960 46 390.9
Orford (Aubin Court) 753.4 761.2 in 1960 45 483.2
Premaydena Hatchery 807.4 821.4 in 1964 43 586.2
Lake Leake (Elizabeth River) 893.6 1296.7 in 1970 39 619.4
Levendale 919.0 923.1 in 1970 39 541.5
York Plains (Handroyd) 527.4 555.6 in 1970 38 396.8
Lewis Hill (St Pauls River) 671.0 702.8 in 1974 33 464.3
Irishtown 1071.8 1258.0 in 1975 28 926.0
Gladstone (Old Post Office) 814.9 946.1 in 1977 27 647.5
Savage River Mine 1787.8 1860.0 in 1975 24 1515.1
St Marys (Clive Street) 1085.8 1121.3 in 1984 22 767.4

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 September 2009
Maximum temperatures
for September
(°C)
Minimum temperatures
for September
(°C)
Rainfall
for September
(millimetres)
Mean for
September
2009
Diff
from
average
Highest for
September
2009
Mean for
September
2009
Diff
from
average
Lowest for
September
2009
Total for
September
2009
Average
for
September
Rank of
September
2009
Fraction of
September
average
Northern (district 91)
Bridport 15.1 +0.4 17.9 23rd 7.3 +0.5 3.8 2nd 82.8 76.4 average 108%
Burnie 15.2 +0.9 19.0 28th 8.1 +1.3 5.2 11th 98.0 87.5 average 112%
Cape Grim BAPS 13.8 +0.5 17.4 12th 9.2 +0.6 7.2 11th 103.6 76.0 high 136%
Cressy Research Station 14.4 −0.3 18.6 12th 5.2 +1.5 −1.0 2nd 75.4 64.4 average 117%
Devonport Airport 14.7 +0.7 17.6 23rd 6.7 +0.8 1.9 10th 86.2 74.6 average 116%
Launceston 15.4 −0.1 19.7 12th 6.3 +1.1 1.6 2nd 71.0 66.5 average 107%
Launceston Airport 14.5   18.7 12th 4.9   1.3 2nd 83.0
Low Head 14.3 +0.4 17.0 27th 9.5 +1.2 5.2 2nd 87.2 65.5 high 133%
Luncheon Hill 12.7 +0.5 18.0 12th 5.6 +0.2 2.7 11th 184.2 178.7 average 103%
Marrawah 14.1 +0.4 19.0 12th 8.1 +0.7 4.0 11th 147.0 105.4 high 139%
Scottsdale 14.1 −0.1 17.5 12th 5.7 +1.0 0.8 2nd 82.6 98.7 average 84%
Sheffield School Farm 13.2 +0.1 16.7 10th 4.9 +0.2 1.6 5th 122.6 128.7 average 95%
Smithton Aerodrome 15.1 +0.3 18.0 12th 6.4 +0.2 0.5 11th 103.0 106.3 average 97%
Wynyard Airport 15.6 +1.3 18.8 10th 5.4 +0.6 0.9 11th 100.0 94.6 average 106%
East Coast (district 92)
Bicheno 16.2 +0.1 22.2 12th 8.2 +0.8 4.6 5th 180.2 44.7 very high 403%
Eddystone Point 15.9 +1.1 21.2 12th 8.8 +0.8 5.4 2nd 158.4 63.7 very high 249%
Fingal 14.8 −0.5 20.7 12th 4.7 +1.5 −0.9 2nd 129.2 49.7 very high 260%
Friendly Beaches 16.4 −0.3 24.0 12th 8.1 +0.6 4.1 11th 99.8 38.8 very high 257%
Lake Leake 11.1 −0.2 16.3 12th 3.4 +1.4 −1.3 2nd 175.0 71.2 very high 246%
Maria Island 14.8   18.6 12th 8.5   4.8 1st 134.8
Orford 15.8 0.0 20.3 12th 6.3 +0.8 2.1 2nd 170.4 52.2 highest 326%
Scamander 16.5 +0.2 22.2 12th 7.4 +0.8 3.8 2nd 146.2 55.2 very high 265%
St Helens Aerodrome 16.0   21.5 12th 7.5   2.7 2nd 123.2
Swansea Post Office 16.2 +0.2 22.4 12th 6.3 +0.5 1.5 20th 151.0 41.1 very high 367%
Midlands (district 93)
Ross 13.8 −0.6 17.9 12th 5.0 +1.4 −0.8 2nd 89.2 54.9 high 162%
Southeast (district 94)
Campania 15.8   20.7 12th 5.7   0.0 11th 115.4
Cape Bruny 14.6 +0.2 20.0 30th 7.5 0.0 3.8 11th 91.0 66.1 high 138%
Cape Bruny Lighthouse 14.1 +0.8 19.1 30th 8.0 +1.0 5.1 11th 106.8 80.8 high 132%
Dover 15.0 +0.3 20.9 30th 5.3 +0.4 −0.1 11th 143.0 83.3 high 172%
Geeveston 15.4 +0.6 19.5 30th 5.0 +0.7 −0.8 11th 144.6 91.9 high 157%
Grove 15.6 +0.8 20.5 30th 5.5 +1.4 0.1 2nd 169.0 74.7 very high 226%
Grove 15.2   20.3 19th 5.0   −0.8 2nd 176.0
Hobart 16.1 +1.0 21.2 30th 7.1 +0.7 3.1 29th 133.8 53.2 very high 252%
Hobart Airport 15.6 +0.3 20.4 12th 6.9 +0.9 2.5 15th 98.0 41.8 very high 234%
Maatsuyker Island Lighthouse 12.8 +0.6 18.0 3rd 7.5 +0.7 3.7 1st 102.0 109.4 average 93%
Melton Mowbray 14.2 −0.5 19.5 12th 5.0 +0.7 −0.5 11th 104.8 54.8 very high 191%
Mount Wellington 5.2 +0.9 9.8 30th −1.1 +0.3 −4.9 1st 225.4 72.0 highest 313%
Tasman Island 12.9   19.3 12th 7.3   3.3 1st 115.4
Tunnack Fire Station 11.8 −0.7 16.0 12th 3.8 +0.6 0.0 2nd 208.2 66.4 very high 314%
Derwent Valley (district 95)
Bushy Park 16.4 +0.9 21.4 12th     −1.7 11th
Maydena Post Office 14.0 +0.3 19.0 30th 4.0 +0.7 −0.7 11th 155.1 140.1 average 111%
Ouse Fire Station 16.0 +0.2 20.9 12th 3.9 +0.2 −1.7 11th 62.0 73.4 average 84%
Tarraleah Village 11.5 +0.3 16.3 13th 2.7 +0.9 −1.9 11th 136.1 119.7 average 114%
Central Plateau (district 96)
Butlers Gorge 10.6 +0.5 15.7 12th 1.8 +0.9 −3.2 11th 186.2 167.8 average 111%
Lake St Clair National Park 10.4 +0.4 16.0 18th 1.6 +0.8 −2.3 29th 241.8 213.4 average 113%
Liawenee 8.5   14.8 18th −0.1   −5.7 29th 149.8
West Coast (district 97)
Hartz Mountain 8.9 +0.2 14.2 30th 2.0 +0.1 −1.6 1st 135.6 99.1 high 137%
Scotts Peak Dam 12.4 +0.2 17.9 3rd 4.6 +0.3 1.1 1st 227.6 210.3 average 108%
Strahan Aerodrome 14.7 +0.4 18.7 19th 6.8 +0.6 3.3 22nd 176.4 136.7 high 129%
Strathgordon Village 12.5 +1.0 17.4 30th 5.1 +0.7 1.5 11th 265.4 276.8 average 96%
Warra 11.6   18.0 30th 3.6   −1.2 11th 204.8
King Island (district 98)
King Island Airport 14.9 +0.3 22.2 12th 9.1 +0.9 5.5 2nd 115.2 88.3 high 130%
Flinders Island (district 99)
Flinders Island Airport 16.0 +0.9 24.7 12th 8.5 +1.0 3.7 2nd 107.0 64.1 high 167%
Hogan Island 15.3   24.7 12th 9.7   5.9 27th 96.4
Antarctica and Macquarie Island (district 300)
Macquarie Island 5.9 +0.5 7.8 28th 2.4 +0.9 −2.1 23rd 69.0 74.1 average 93%


Notes

This statement has been prepared based on information available at 10 am on Thursday 1 October 2009 Some checks have been made on the data, but it is possible that results will change as new information becomes available. This Summary will most likely not be updated; more complete results will be given in the Monthly Weather Review published later this month.

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