Monday, 5 January 2009 - Monthly Climate Summary for Tasmania - Product code IDCKGC17R0
It was cool end to the year with most temperatures in December cooler than normal and only a few warm days. Nights were also cold, especially near the start of the month when Liawenee dropped to −4.5°C, the third coldest December temperature for Tasmania. A low pressure system on the 13th brought flooding rain to the northeast and led to above average rainfall there and in the northwest, but rainfall for the rest of the state was mostly near average.
Few warm days: It was a cool start to summer
with temperatures for the first three weeks generally below
average and struggling to reach into the low 20s. There were even
snowfalls on the higher peaks for a number of days in the first week.
The coldest days were behind cold fronts on the 1st to 3rd and 10th,
and in easterly winds with cloud and rain on the 13th. It finally
warmed up on the 21st and 22nd as a northerly pattern developed.
Temperatures reached into the low 30s in the southeast on the 22nd, and
this combined with very strong winds gusting over 100 km/h to
produce some extreme fire dangers. The following week was mild, but a
series of cold fronts on the final three days saw a
return to cooler conditions with highland snow. Average daytime
temperatures for the month were mostly 1 to 2 degrees below normal, and
most places had their coolest December since 2001.
Cool nights too: There were several cold nights in the first half of the month, especially on the 4th and 10th when light winds and a cold, clear airmass allowed temperatures to drop below 2°C across much of the state. On these mornings, temperatures were up to 10 degrees below average and several sites had their coldest December night in over 10 years. Liawenee fell to −4.5°C early on the 10th, the third coldest December temperature recorded in Tasmania and the coldest since 1969. Overnight temperatures were milder in the last part of the month, but mean minima for December were still around a degree below normal. Many locations had their coolest December nights since 1996 or 2001.
Flooding in the northeast: A low pressure system to the northwest of Tasmania on the 12th intensified as it moved near Flinders Island on the 13th and brought rainfalls in excess of 80 mm to many sites in the northeast. St Marys was the wettest location, receiving 173 mm over 2 days, including 103 mm in the 24 hours to 9am on the 14th. The rain caused moderate flooding of the South Esk River at Fingal and flooding of several buildings on Flinders Island. Wind gusts reached 113 km/h at Swan Island, but Flinders Island bore the brunt of the strong and gusty southeasterly winds which accompanied the low, and significant damage was reported.
Rainfall mostly around average: Apart from a few sites in the southeast, rainfall for December was average or above. The rain event on the 13th led to wetter than normal conditions in the northeast and northwest, and a series of thunderstorms on the 9th, 16th, 18th and 20th pushed totals above average for a few sites in the lower east. Many sites in the east had their wettest December since 1993 or 1995. Most of the rainfall in the west came from a series of cold fronts near the start and end of the month, each of which saw falls in the order of 15 to 25 mm. These fronts were not strong enough to bring much rainfall to the southeast, and a number of sites there had below average rainfall. Hobart Airport and Ross were the driest locations in the state, receiving only 25.6 mm for the month.
|31.0°C at Dover and Geeveston on the 22nd|
|Warmest days on average|
Highest mean daily maximum temperature
21.7°C at Bushy Park (Bushy Park Estates)|
|Coolest days on average|
Lowest mean daily maximum temperature
9.4°C at Mount Read|
Lowest daily maximum temperature
3.6°C at Mount Read on the 7th|
−4.5°C at Liawenee on the 10th|
|Coolest nights on average|
Lowest mean daily minimum temperature
|1.0°C at Mount Wellington|
|Warmest nights on average|
Highest mean daily minimum temperature
12.1°C at Swan Island|
Highest daily minimum temperature
16.2°C at Hobart (Ellerslie Road) on the 23rd|
Highest total rainfall
355.6 mm at Mount Read|
Lowest total rainfall
|25.6 mm at Hobart Airport and Ross|
Highest daily rainfall
102.6 mm at St Marys (Clive Street) on the 14th|
|Highest wind gust||
128 km/h at Mount Wellington on the 22nd|
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 December 2008|
|Northern (district 91)|
|Cape Grim BAPS||16.0||−1.2||20.6||22nd||10.9||−1.0||8.4||10th||83.4||44.5||very high||187%|
|Cressy Research Station||21.0||27.8||23rd||7.0||−2.2||4th||51.6|
|Launceston Airport Comparison||19.7||−1.5||26.0||22nd||8.1||−0.7||1.6||4th||51.8||50.7||average||102%|
|Sheffield School Farm||17.7||−1.9||23.7||27th||7.1||−2.0||1.2||4th||61.6||61.7||average||100%|
|Smithton Aerodrome||18.2||−1.2||22.3||14th||8.6||−1.1||1.1||10th||118.6||63.2||very high||188%|
|East Coast (district 92)|
|St Helens Aerodrome||19.7||26.1||27th||10.6||4.3||4th||140.8|
|Swansea Post Office||20.1||−0.6||29.4||22nd||9.4||−1.1||3.7||10th||66.2||59.9||average||111%|
|Midlands (district 93)|
|Southeast (district 94)|
|Cape Bruny||17.4||−0.8||30.9||22nd||9.5||−1.2||6.5||4th||32.0||61.3||very low||52%|
|Cape Bruny Lighthouse||16.6||−0.3||29.9||22nd||9.7||−0.7||7.0||4th||44.8||76.9||low||58%|
|Maatsuyker Island Lighthouse||14.2||−1.5||26.9||22nd||8.7||−0.8||5.4||2nd||66.0||90.4||average||73%|
|Tunnack Fire Station||17.8||−1.9||24.4||27th||6.4||−1.1||−1.0||4th||75.8||52.0||high||146%|
|Derwent Valley (district 95)|
|Maydena Post Office||17.6||−2.2||28.2||22nd||7.2||−0.2||1.6||10th||97.5||89.6||average||109%|
|Ouse Fire Station||21.0||−2.1||30.3||21st||7.9||−0.7||1.4||10th||33.6||37.1||average||91%|
|Central Plateau (district 96)|
|Lake St Clair National Park||15.0||−2.4||24.8||21st||4.2||−0.9||−1.0||10th||139.4||134.6||average||104%|
|West Coast (district 97)|
|Scotts Peak Dam||17.1||−1.3||28.6||22nd||6.5||−1.5||2.7||10th||151.3|
|King Island (district 98)|
|King Island Airport||17.4||−1.2||26.3||22nd||10.2||−0.7||2.8||11th||63.6||50.9||high||125%|
|Flinders Island (district 99)|
|Flinders Island Airport||18.8||−1.3||25.5||5th||11.3||−0.4||4.5||11th||134.4||58.0||very high||232%|
|Antarctica and Macquarie Island (district 300)|
This statement has been prepared based on information available at 9 am on Monday 5 January 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
(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.