Monday, 12 January 2009 - Monthly Climate Summary for Tasmania - Product code IDCKGC17R0

Tasmania in September 2008: Some very cold nights, dry in the southeast

September saw average or above rainfall across the state, except in the southeast and through northern parts of Bass Strait. There were many windy days, as is typical for this time of the year. Days were sometimes warm and sometimes cool, and nights were extremely cold at the start of the month.

This summary updates the previous version, issued on 1 October 2008.

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

Details

Dry in the southeast but wetter elsewhere: The pattern of below average rainfall in southeastern Tasmania continued in September with many locations receiving only half of their normal September total. Nugent and Orielton in the southeast had their lowest total September rainfall on record, but the driest location was Seven Mile Beach which received only 13.2 mm for the month. Northern parts of the Bass Strait Islands were also drier than usual, but the rest of the state recorded near or above average rainfall. More than 50 mm fell in many parts of the Midlands, where some locations had their wettest month for almost three years. The most significant rain fell on the 1st, 12th, 15th and 22nd as active cold fronts crossed the state, bringing in excess of 30 mm to the west and 10 to 20 mm to northern locations. Despite the wet September in some parts of the state, totals for most of Tasmania are well below average so far this year.

Many windy days: September saw many days of strong winds, as is typical for this time of the year. It was particularly windy from the 12th to the 15th and again from the 20th to the 23rd, as multiple fronts crossed the state while a high pressure system persisted over the Tasman Sea. Strong winds also lead to waves as high as 15 metres near Cape Sorell on the 16th, and combined with warm temperatures on the 25th and 26th to produce the first very high fire dangers for the season. Several buildings were damaged when gusts reached 106 km/h in Hobart early on the 26th, but this is still well short of the 128 km/h recorded in April this year. There were 7 days with gusts over 80 km/h in Hobart, compared to the September average of 3 such gusty days.

Warm in the east, cooler elsewhere: Vigorous cold fronts in September saw bursts of warm weather  followed by a few cool days. The warmest days occurred ahead of cold fronts on the 11th to 14th, 19th and 25th, while the coldest days (the 2nd, 3rd, 8th and 16th) followed cold fronts and kept temperatures in the low teens. Over the whole month, maxima were generally around a degree above average in the east (an artefact of the predominately westerly winds) and half a degree below average elsewhere. The temperature exceeded 20 C on six days at Bicheno, making it one of the warmest locations in the state. 

Some very cold nights: The first part of the month saw a number of very cold nights, particularly on the 3rd and 4th when Ross, Swansea, Fingal and Bicheno fell below their coldest winter temperature for this year and Bushy Park, Fingal and Lake Leake set new records for their lowest September temperature. In contrast, windy conditions during the 24 hours to 9am on the 26th meant that the temperature at Swansea didn't fall below 15 C, the warmest night for the month. Strong winds also kept overnight temperatures up on the 12th to 14th and on the morning of the 22nd. Across the whole month, minima were generally half a degree below average - except for a few sites in the west and southeast which were slightly above average. Many locations had their coolest September nights on average since 2003.

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
23.5 C at Campania on the 25th
Warmest days on average
Highest mean daily maximum temperature
17.2 C at Bicheno
Coolest days on average
Lowest mean daily maximum temperature
4.0 C at Mount Read
Coldest day
Lowest daily maximum temperature
-1.4 C at Mount Wellington on the 16th
Coldest night
Lowest temperature
-7.4 C at Liawenee on the 3rd
Coolest nights on average
Lowest mean daily minimum temperature
-1.6 C at Mount Wellington
Warmest nights on average
Highest mean daily minimum temperature
9.2 C at Hogan Island
Warmest night
Highest daily minimum temperature
15.0 C at Swansea Post Office on the 26th
Wettest overall
Highest total rainfall
425.1 mm at Cradle Valley (Waldheim)
Driest overall
Lowest total rainfall
13.2 mm at Seven Mile Beach
Wettest day
Highest daily rainfall
43.2 mm at Strathgordon Village on the 16th
Highest wind gust
156 km/h at Mount Wellington on the 26th

Records


Record lowest total September rainfall
Total rainfall
for September 2008 (mm)
Previous lowest
for September
Years of
record
Average for
September
Orielton (East Orielton Road) 13.4 13.6 in 1978 40 43.2
Nugent (Twilight Valley) 24.8 26.2 in 1999 26 67.4


Lowest total September rainfall for at least 20 years
Total rainfall
for September 2008 (mm)
Most recent lower
for September
Years since
lower
Average for
September
Seven Mile Beach (Royal Hobart Golf Club 13.2 10.3 in 1978 29 41.1
Bream Creek (Stroud) 20.4 8.0 in 1981 26 53.4
Opossum Bay 21.2 17.8 in 1986 22 41.0



Record lowest September temperature
Lowest temperature
in September 2008 (C)
Previous lowest
for September
Years of
record
Normal for
September
Bushy Park (Bushy Park Estates) -3.7 on the 4th -3.4 on the 8th in 2003 48 3.9
Fingal (Legge Street) -6.2 on the 4th -4.8 on the 13th in 1993 24 3.1
Lake Leake (Elizabeth River) -6.3 on the 4th -6.1 on the 29th in 1994 20 1.9



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 2008
Maximum temperatures
for September
(C)
Minimum temperatures
for September
(C)
Rainfall
for September
(millimetres)
Mean for
September
2008
Diff
from
average
Highest for
September
2008
Mean for
September
2008
Diff
from
average
Lowest for
September
2008
Total for
September
2008
Average
for
September
Rank of
September
2008
Fraction of
September
average
Northern (district 91)
Bridport 14.5 -0.2 17.1 13th 6.4 -0.4 -0.1 3rd 77.1 76.0 average 101%
Burnie 14.2 -0.1 17.0 13th 7.2 +0.5 3.4 17th 87.4 87.4 average 100%
Cape Grim BAPS 13.5 +0.1 17.1 13th 8.5 0.0 4.0 4th 84.4 74.8 average 113%
Cressy Research Station 14.1 -0.6 16.3 7th 3.3 -0.5 -4.4 3rd 71.0 68.7 average 103%
Devonport Airport 14.0 0.0 16.7 7th 5.6 -0.3 0.1 3rd 54.5 74.3 average 73%
Launceston 15.0 -0.5 17.5 19th 4.9 -0.2 -1.6 3rd 81.6 66.3 average 123%
Launceston Airport 14.1   17.0 19th 3.2   -3.0 3rd 74.6
Launceston Airport Comparison 13.3 -0.7 15.9 19th 3.8 -0.4 -2.4 3rd 86.0 64.1 high 134%
Low Head 13.5 -0.4 15.9 13th 8.2 -0.1 2.8 3rd 50.0 63.5 low 79%
Luncheon Hill 11.0 -1.2 16.1 6th 4.0 -1.4 -0.1 16th 183.0 178.3 average 103%
Marrawah 13.7 0.0 17.2 13th 7.6 +0.2 3.3 3rd 97.2 104.3 average 93%
Powranna 13.7 -0.7 16.1 13th 3.3 -0.6 -3.0 3rd 119.3 64.0 very high 186%
Scottsdale 13.4 -0.8 16.3 13th 3.7 -1.0 -1.9 3rd 84.4 99.1 average 85%
Sheffield School Farm 12.2 -0.8 15.5 13th 3.8 -0.8 -1.8 3rd 121.8 134.9 low 90%
Smithton Aerodrome 14.6 -0.2 18.4 13th 6.0 -0.2 -0.6 3rd 91.4 106.6 average 86%
Wynyard Airport 14.5 +0.3 16.9 13th 4.2 -0.7 -0.9 8th 76.3 94.2 average 81%
East Coast (district 92)
Bicheno 17.2 +1.2 22.6 19th 6.9 -0.4 1.7 4th 31.0 43.1 average 72%
Eddystone Point 15.7 +0.9 19.5 19th 7.8 -0.2 3.5 3rd 45.6 62.8 average 73%
Fingal 15.4 +0.1 20.9 19th 2.0 -1.2 -6.2 4th 51.6 49.1 average 105%
Friendly Beaches 17.1 +0.4 23.2 19th 7.1 -0.4 1.2 17th 25.8 33.3 average 77%
Lake Leake 11.3 0.0 14.6 19th 1.1 -0.8 -6.3 4th 103.8 70.3 high 148%
Maria Island 15.6   20.0 13th 8.1   4.3 8th 16.6
Orford 16.4 +0.6 20.2 20th 5.4 -0.1 -0.6 4th 38.2 50.1 average 76%
Scamander 16.7 +0.4 21.7 19th 6.0 -0.7 1.2 3rd 60.0 51.6 high 116%
St Helens Aerodrome 15.8   20.1 19th 5.9   -0.1 3rd 53.4
Swan Island 14.3   16.4 19th 8.7   4.5 3rd 63.8
Swansea Post Office 17.0 +1.0 22.1 19th 5.1 -0.6 -1.5 10th 23.0 40.2 average 57%
Midlands (district 93)
Ross 14.3 -0.1 17.0 19th 3.3 -0.3 -4.8 4th 72.4 52.6 average 138%
Southeast (district 94)
Bull Bay 15.6 +0.8 22.0 25th 6.5 -0.3 2.5 29th 21.0 51.5 very low 41%
Campania 16.6   23.5 25th 5.1   -1.2 3rd 19.2
Cape Bruny 14.6 +0.2 20.0 25th 7.1 -0.5 3.4 4th 63.0 64.0 average 98%
Cape Bruny Lighthouse 14.0 +0.7 19.6 25th 6.8 -0.2 3.0 29th 85.0 80.6 average 105%
Dover 14.8 +0.2 21.3 25th 4.8 -0.1 -0.6 4th 72.4 82.5 average 88%
Geeveston 14.9 +0.2 21.4 25th 4.5 +0.2 -1.6 4th 111.8 90.5 high 124%
Grove 15.3 +0.5 22.0 25th 4.8 +0.8 -2.6 4th 62.6 73.1 average 86%
Grove 15.1   21.7 25th 4.1   -3.2 4th 67.8
Hobart 16.5 +1.5 22.6 25th 7.1 +0.7 2.2 4th 26.8 52.5 low 51%
Hobart Airport 16.6 +1.3 22.8 25th 6.5 +0.5 0.9 4th 15.0 40.7 very low 37%
Maatsuyker Island Lighthouse 12.0 -0.2 19.1 13th 6.7 0.0 3.9 23rd 119.6 109.5 average 109%
Melton Mowbray 14.6 -0.1 20.9 25th 4.0 -0.3 -3.2 4th 35.4 50.6 low 70%
Mount Wellington 4.7 +0.4 11.3 25th -1.6 -0.3 -5.1 29th
Tasman Island 13.2   19.1 13th 6.6   2.3 29th 45.0
Tunnack Fire Station 12.1 -0.4 16.8 13th 2.5 -0.7 -3.2 3rd 30.8 53.5 low 58%
Derwent Valley (district 95)
Bushy Park 15.9 +0.5 22.7 25th 2.7 -1.2 -3.7 4th 45.8 53.7 average 85%
Maydena Post Office 13.2 -0.5 19.8 25th 3.3 -0.1 -2.7 5th 177.9 139.1 average 128%
Ouse Fire Station 15.2 -0.6 20.7 25th 3.6 -0.1 -3.2 4th 88.4 74.5 average 119%
Tarraleah Village 10.7 -0.5 15.6 25th 2.5 +0.7 -2.7 3rd 210.6 119.5 very high 176%
Central Plateau (district 96)
Butlers Gorge 9.5 -0.6 14.7 25th 1.0 +0.1 -5.2 4th 295.0 165.2 very high 179%
Lake St Clair National Park 9.2 -0.8 14.3 25th 1.1 +0.3 -5.5 4th 310.0 211.9 high 146%
Liawenee 7.5   11.7 25th -1.0   -7.4 3rd 168.4
West Coast (district 97)
Hartz Mountain 8.0 -0.7 15.4 11th 1.2 -0.6 -1.8 29th 102.2 96.0 average 106%
Mount Read 4.0 -1.5 9.1 25th -0.4 -0.7 -3.7 9th
Scotts Peak Dam 11.7 -0.5 18.2 11th 4.0 -0.3 0.6 3rd 245.2
Strahan Aerodrome 14.3 0.0 18.3 13th 6.6 +0.4 0.0 4th 165.6 153.2 average 108%
Strathgordon Village 11.6 +0.1 16.5 13th 4.0 -0.4 -0.5 5th 370.6 277.1 high 134%
Warra 10.9   16.9 25th 3.1   -1.2 4th 285.8
King Island (district 98)
King Island Airport 14.8 +0.2 20.1 13th 8.3 +0.2 3.7 3rd 77.0 87.5 average 88%
Flinders Island (district 99)
Flinders Island Airport 16.5 +1.4 23.1 19th 7.4 -0.1 -0.5 4th 43.0 63.4 low 68%
Hogan Island 15.0   20.9 13th 9.2   6.1 17th 32.2
Antarctica and Macquarie Island (district 300)
Macquarie Island 5.5 +0.2 7.0 13th 2.3 +0.8 -0.6 25th 91.6 73.7 high 124%


Notes

This statement has been prepared based on information available at 10 am on Monday 12 January 2009. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

Normals 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 ("normal") 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, normal in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of normal 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