Monday, 1 October 2007 - Monthly Climate Summary for Tasmania - Product code IDCKGC17R0

Tasmania in September 2007: A wet and windy end

Summary

A burst of westerly winds and several cold fronts near the end of the month meant rainfall totals for September 2007 were close to normal in many parts of the state, but in the east it was yet  another in the long series of drier-than-usual months that Tasmania has experienced since the start of 2006. Warm days were more prevalent than cool ones, but there were several quite cold nights.

Details

Some rain, but dry in the east: There were some moderate to heavy falls of rain during the month, particularly as fronts crossed the state around the 2nd, the 24th and particularly over the final four days. Nonetheless, for most of the month most of the state was relatively dry, especially in the east. Totals for the month were below average near the East Coast and the northern Midlands, and well below average on the lower East Coast. South Bruny Island and parts of the inland northwest had totals above the long-term September average. As is often the case when westerly winds bring the rain, there was a stark contrast between the western highlands (with well over 200 mm) and the lower East Coast (with less than 20 mm).

Long-term deficits remain: Despite the recent rain and notable rainfall events during August and May, most of the last 21 months have been much drier than normal across Tasmania. The last extended period of above-average rain was at the end of 2005. To even begin to make up these deficits will require a sustained period of above-average falls. Just one example is Burnie, where the 971 mm recorded over the last 21 months is 735 mm less than the long-term average for the same period. The record wet October-to-December in 2005 provided Burnie with 424 mm, so even a repeat of that extraordinary rain would not remove the current long-term deficit. Similar stories emerge in other parts of the state.

Mild days: There were several warm days during September, notably the 19th when temperatures into the low 20s were reported in the southeast. There were very few particularly cold days, the main exception being the 3rd. The result was mean maximum temperatures above the long-term average across the state, typically by around half a degree in the north and about a degree in the southeast.

Some cold nights: There were several quite cold nights during the month: a very cold morning on the 4th, with another (in most areas) on the 9th, again on the 16th and both the 22nd and 23rd. A number of mild nights (notably the 2nd and 14th) were not enough to counter the colder ones, so mean minimum temperatures were below average in most parts of the state, typically by half a degree, although the northeast and southeast coasts were a little above average.

Less westerly winds than usual — until the end: September is often a time of strong westerly winds across Tasmania, but this month it was only the final week that saw sustained westerly winds and cold fronts. It was rain from that series of fronts that prevented the north and west from having another dry month, but it was accompanied by many gusts well over 100 km/h.

Further information

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

Extremes

Hottest day
Highest temperature
22.4°C at Dover on the 19th
Warmest days on average
Highest mean daily maximum temperature
17.1°C at Friendly Beaches
Coolest days on average
Lowest mean daily maximum temperature
5.7°C at Mount Read
Coldest day
Lowest daily maximum temperature
–1.6°C at Mount Wellington on the 3rd
Coldest night
Lowest temperature
–6.3°C at Liawenee on the 4th
Coolest nights on average
Lowest mean daily minimum temperature
–0.9°C at Liawenee
Warmest nights on average
Highest mean daily minimum temperature
9.4°C at Swan Island
Warmest night
Highest daily minimum temperature
13.0°C at Bicheno (Council Depot) on the 14th
Wettest overall
Highest total rainfall
293.6 mm at Lake Margaret Power Station
Driest overall
Lowest total rainfall
12.8 mm at Swansea Post Office
Wettest day
Highest daily rainfall
66.8 mm at Zeehan (West Coast Pioneers Museum) on the 30th
Highest wind gust
135 km/h at Hogan Island on the 28th
and Maatsuyker Island Lighthouse on the 29th
and Scotts Peak Dam on the 29th

Records

No monthly records appear to have been set in September 2007.

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 2007
Maximum temperatures
for September
(°C)
Minimum temperatures
for September
(°C)
Rainfall
for September
(millimetres)
Mean for
September
2007
Diff
from
normal
Highest for
September
2007
Mean for
September
2007
Diff
from
normal
Lowest for
September
2007
Total for
September
2007
Normal
for
September
Rank of
September
2007
Fraction of
September
normal
Northern (district 91)
Bridport 14.9 +0.2 19.5 17th 7.3 +0.4 1.8 4th 57.3 76.2 normal 75%
Burnie 14.5 +0.2 19.4 11th 7.9 +1.2 3.7 4th 76.4 87.4 normal 87%
Cape Grim BAPS 13.7 +0.4 16.4 13th 8.5 0 4.1 4th 92.4 74.3 normal 124%
Cressy Research Station 14.6 17.7 12th 3.2 –3.1 23rd 45.6
Devonport Airport 14.5 +0.5 18.1 17th 6.1 +0.2 0.1 4th 54.4 74.5 normal 73%
Launceston 15.8 +0.3 19.6 17th 5.2 0 –0.5 23rd 49.2 65.6 low 75%
Launceston Airport 15.0 18.1 17th 3.7 –2.2 22nd 41.4
Launceston Airport Comparison 14.3 +0.3 17.4 17th 3.9 –0.4 –2.2 4th 46.8 63.8 low 73%
Low Head 14.1 +0.2 16.5 17th 8.3 0 2.9 22nd 59.0 64.4 normal 92%
Luncheon Hill 12.8 +0.5 17.7 8th 5.6 +0.1 0.6 4th 187.0 177.9 normal 105%
Marrawah 14.0 +0.3 16.2 8th 7.8 +0.4 1.5 4th 109.4 104.5 normal 105%
Powranna 14.5 +0.2 18.0 17th 3.4 –0.5 –2.6 4th 42.4 60.6 low 70%
Scottsdale 14.1 –0.2 18.5 17th 4.6 –0.2 –2.5 22nd 97.0 99.6 normal 97%
Sheffield School Farm 13.1 0 16.9 25th 4.1 –0.7 –1.8 4th 118.4 136.3 low 87%
Smithton Aerodrome 15.1 +0.4 18.0 25th 5.7 –0.6 –1.4 22nd 97.6 108.0 normal 90%
Wynyard Airport 14.4 +0.2 18.3 11th 4.8 –0.1 –0.9 4th 106.0 94.7 normal 112%
East Coast (district 92)
Bicheno 16.9 +0.8 20.3 17th 8.6 +1.3 3.9 23rd 17.7 43.2 low 41%
Eddystone Point 16.1 +1.3 19.2 17th 8.4 +0.4 2.7 22nd 39.4 63.0 low 63%
Fingal 15.0 –0.3 18.8 18th 3.7 +0.5 –3.7 23rd 28.2 49.0 low 58%
Friendly Beaches 17.1 +0.5 21.1 18th 7.5 0 2.2 23rd 19.6 34.0 very low 58%
Lake Leake 11.6 +0.3 15.2 19th 1.5 –0.5 –4.9 23rd 42.8 70.0 low 61%
Maria Island 15.3 18.1 27th 8.8 5.1 4th 27.6
Orford 16.2 +0.5 20.0 18th 5.0 –0.6 –1.3 5th 23.2 50.3 low 46%
Scamander 16.7 +0.4 19.5 18th 7.5 +0.9 2.7 1st 21.2 51.2 low 41%
St Helens Aerodrome 15.8 18.1 21st 7.1 1.7 23rd 20.0
Swan Island 14.8 17.3 25th 9.4 4.6 22nd 43.4
Swansea Post Office 16.9 +0.9 20.9 18th 6.2 +0.4 –1.5 23rd 12.8 40.4 very low 32%
Midlands (district 93)
Ross 14.9 +0.5 17.9 8th 2.7 –1.0 –3.7 22nd 30.0 51.2 low 59%
Southeast (district 94)
Bull Bay 15.0 +0.3 21.5 19th 6.6 –0.3 2.8 22nd 59.8 52.7 normal 113%
Campania 16.4 21.4 18th 5.2 –0.1 5th 37.0
Cape Bruny 14.8 +0.5 22.1 19th 7.6 0 4.7 22nd 79.4 64.1 high 124%
Cape Bruny Lighthouse 14.2 +1.0 21.0 19th 7.8 +0.8 4.0 4th 91.6 80.5 high 114%
Dover 15.2 +0.7 22.4 19th 4.6 –0.4 –0.8 5th 82.6 82.7 normal 100%
Geeveston 15.6 +0.9 21.6 19th 4.0 –0.4 –1.7 5th 98.4 90.0 normal 109%
Grove 16.1 +1.3 21.5 19th 3.9 –0.2 –1.4 23rd 73.2 73.3 normal 100%
Grove 15.8 21.1 19th 3.2 –2.3 23rd 77.8
Hobart 15.8 +0.8 20.9 18th 6.9 +0.5 2.8 5th 63.0 52.7 high 120%
Hobart Airport 16.3 +1.0 21.4 18th 6.3 +0.3 1.2 5th 33.2 41.2 normal 81%
Maatsuyker Island Lighthouse 13.0 +0.9 18.0 23rd 7.8 +1.0 4.7 4th 102.8 109.5 normal 94%
Melton Mowbray 14.5 –0.2 19.5 18th 3.8 –0.6 –0.9 5th 56.0 52.0 normal 108%
Mount Wellington 5.9 +1.7 11.6 18th –0.2 +1.2 –4.8 4th
Tasman Island 12.8 16.2 19th 7.6 2.7 22nd 66.2
Tunnack Fire Station 12.6 0 15.3 7th 2.9 –0.5 –3.6 4th 34.6 55.8 low 62%
Derwent Valley (district 95)
Bushy Park 16.5 +1.0 21.9 19th 3.1 –0.8 –3.0 5th 63.0 53.8 normal 117%
Maydena Post Office 14.1 +0.4 20.0 19th 2.9 –0.5 –1.5 7th 131.4 136.5 normal 96%
Moogara 12.1 +0.8 16.0 19th 3.7 +0.5 0.5 3rd 89.6 92.1 normal 97%
Ouse Fire Station 15.7 –0.1 20.5 18th 2.5 –1.4 –4.2 23rd 66.6 73.1 normal 91%
Tarraleah Village 12.1 +1.0 16.6 18th –2.8 4th 111.9 118.3 normal 95%
Central Plateau (district 96)
Lake St Clair National Park 10.8 +0.7 15.2 8th 0.4 –0.3 –4.4 4th 201.8 205.7 normal 98%
Liawenee 8.5 13.7 18th –0.9 –6.3 4th 107.4
West Coast (district 97)
Hartz Mountain 9.9 +1.3 15.7 19th 2.3 +0.4 –2.0 4th 100.0 95.5 normal 105%
Mount Read 5.7 +0.1 12.4 8th 0.6 +0.1 –4.0 4th
Scotts Peak Dam 13.5 19.3 13th 4.4 0.1 4th 200.2
Strahan Aerodrome 15.2 +1.0 19.2 13th 6.1 0 –0.3 5th 147.8 152.5 normal 97%
Strathgordon Village 12.6 +1.0 17.5 13th 3.9 –0.3 –1.0 5th 283.4 274.8 normal 103%
Warra 11.9 18.4 19th 3.4 –1.8 4th 226.8
King Island (district 98)
King Island Airport 15.4 +1.0 19.9 23rd 8.3 +0.1 1.1 22nd 68.2 87.5 normal 78%
Flinders Island (district 99)
Flinders Island Airport 15.3 +0.3 18.3 19th 7.6 +0.1 –1.2 23rd 27.0 63.7 low 42%
Hogan Island 14.2 17.7 19th 9.3 6.6 29th 59.4
Macquarie Island (district 300)
Macquarie Island 5.9 +0.5 6.9 28th 2.0 +0.5 –1.9 4th 75.2 73.4 normal 102%

Notes

This statement has been prepared based on information available at 10 am on Monday, 1 October 2007. 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 "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
Tasmania and Antarctica Climate Services Centre
Bureau of Meteorology
Phone (03) 6221 2043
Email climate.tas@bom.gov.au