Tuesday, 1 May 2012 - Monthly Climate Summary for Tasmania - Product code IDCKGC17R0

Tasmania in April 2012: Very warm, especially at the start

April 2012 was much warmer than usual despite a couple of cold periods around the 9th and 29th. Several sites had their warmest start to April on record during the first six days. Most areas had near average rainfall, although the southeast was drier than usual with less than 30 mm falling at many locations.

• Record warm April days for Hobart
• 67 mm in 90 minutes at Maatsuyker Island
• Waves to 15 metres in the west on the 29th
• Chilly -4.3 °C at Ross on the 30th

Extremes Maps Records Summaries Important notes the top

A record warm start

Several sites around the state had their warmest start to April on record between the 1st and 6th. Daytime temperatures averaged 3 to 6 degrees warmer than usual for this time of the year, peaking at 29.1 °C at Ouse on the 5th, while overnight temperatures were 1 to 4 degrees above average after a couple of cool nights in some areas. The warmth was caused by a deep low pressure system well to the south of the Bight that combined with a ridge of high pressure over the Tasman Sea to direct a warm, generally northwesterly airflow over Tasmania.

Cold at times, but much warmer than usual overall

The coldest part of the month occurred between the 7th and 10th when several cold fronts crossed the state and southwesterly winds prevailed. Mount Wellington only reached -0.7 °C on the 9th as snow fell to around 600 metres, and Ross dropped to -4.0 °C early on the 10th. 

Warmer conditions returned on the 11th, and temperatures remained mostly above average until near the end of the month. A moist northeasterly airstream between the 19th and 21st brought the warmest nights, peaking on the 20th when Devonport (17.4 °C) and Maydena (14.0 °C) both had their highest April minimum temperature on record. Flinders Island had the two warmest nights of the month with 18.2 °C on the 20th and 17.9 °C on the 19th.

A cold front on the 28th brought a wintery end to the month with much cooler than usual temperatures, showers, snow to around 800 metres, destructive winds and large swells. The waverider near Cape Sorell reached 15.3 metres early on the 29th and swells reached 8 metres at Maatsuyker Island and 6 metres at Cape Bruny. It was cold and frosty on the morning of the 30th with the temperature at Ross falling to -4.3 °C.

On average, both maximum and minimum temperatures were up to two degrees warmer than usual for April. Some sites had their warmest average April maximum or minimum temperature on record.

A few bursts of rain and several thunderstorms

Tasmanian rainfall in April mostly came from cold fronts between the 6th and 9th and on the 28th, and low pressure systems between the 19th and 25th. There were thunderstorms on nearly all of these days and quite widespread hail on the 9th and 23rd; this is relatively uncommon for Tasmania. Thunderstorms in the far south early on the 24th brought exceptionally heavy rain to Maatsuyker Island with 67 mm falling in just 90 minutes. Maatsuyker's daily total reached 113 mm, making it their third wettest day in over 100 years, and their monthly total of 206 mm was their highest April rainfall total since 1986. Intense rain also fell at Friendly Beaches on the 20th, with 26 mm recorded in just one hour.

For the whole month, much of the state had near average rainfall. The southeast, including the lower Midlands, was drier than usual with many sites recording less than 30 mm. Dodges Ferry, with just 13.6 mm, was the driest site. The far south had more rain then usual, as did the north around Sheffield and Deloraine where monthly totals exceeded 80 mm. Mount Read was the wettest site, with at least 291 mm falling during the month (it is likely some snow was lost).

Record warm in Hobart

April was especially warm in Hobart with a near-record high average temperature of 15.0 °C (the record is 15.1 °C). Nights averaged at 10.5 °C, over a degree warmer than usual, while days averaged at a record 19.6 °C. The warmth was prominent at the start of the month with an average maximum temperature of 24.5 °C for the first six days. The 14th and 19th were also warm, making six days when the temperature reached at least 24 °C; this hasn't happened before in Hobart in April. 

Despite warm conditions overall, there were still some cold days with snow covering the mountain on the 9th and 29th. The temperature only reached 12.5 °C on the 9th, and dropped to 4.0 °C on the morning of the 30th. In contrast, the warmest night was 16.3 °C on the 20th and the warmest day was 28.9 °C on the 5th. 

Rainfall was well below average with just 22 mm for the month, around 40% of normal. The long-term average for April is 52 mm.

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Extremes in April 2012
Hottest day	29.1 °C at Ouse Fire Station on the 5th
Warmest days on average	20.2 °C at Campania (Kincora)
Coolest days on average	9.5 °C at Mount Read
Coldest day	-0.7 °C at Mount Wellington on the 9th
Coldest night	-4.3 °C at Ross (The Boulevards) on the 30th
Coolest nights on average	3.1 °C at Liawenee
Warmest nights on average	13.3 °C at Swan Island
Warmest night	18.2 °C at Flinders Island Airport on the 20th
Warmest on average overall	16.0 °C at Swan Island
Coolest on average overall	6.6 °C at Mount Wellington
Wettest overall	290.6 mm at Mount Read **
Driest overall	13.6 mm at Dodges Ferry
Wettest day	113.2 mm at Maatsuyker Island Lighthouse on the 24th
Highest wind gust	150 km/h at Hogan Island on the 7th

** The true total at Mount Read is probably higher, as it is likely some snow was lost.

Extremes Maps Records Summaries Important notes the top

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Maps
	Observed	Anomaly	Decile rank
Total rainfall
Mean daily maximum temperatures
Mean daily minimum temperatures

Click on a map to show it full size in a pop-up window

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Highest total April rainfall for at least 20 years
	Total rainfall for April 2012 (mm)	Most recent April at least this wet		Years since wetter	Average for April
Maatsuyker Island Lighthouse	206.0	237.6	in 1986	26	108.9

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Record highest April mean daily maximum temperature
	Mean daily maximum temperature for April 2012 (°C)	Previous warmest for April		Years of record	Average for April
Hobart (Ellerslie Road)	19.6	= 19.6	in 1993	130	17.3

Highest April mean daily maximum temperature for at least 20 years
	Mean daily maximum temperature for April 2012 (°C)	Most recent April at least this warm		Years since warmer	Average for April
Cape Sorell	17.6	17.8	in 1904*	67	15.4
Maatsuyker Island Lighthouse	15.8	16.7	in 1989	23	14.5

* note: there are gaps in the historical record at this site, so it is possible a higher value has gone unreported.

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Record highest April daily minimum temperature
	Highest daily minimum temperature in April 2012 (°C)		Previous warmest for April		Years of record	Average for April
Devonport Airport	17.4	on the 20th	16.7	on the 1st in 1994	21	8.7
Maydena Post Office	14.0	on the 20th	13.4	on the 3rd in 2005	20	5.4

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Record highest April mean daily minimum temperature
	Mean daily minimum temperature for April 2012 (°C)	Previous warmest for April		Years of record	Average for April
Butlers Gorge	5.3	= 5.3	in 1956	49	3.3
Strathgordon Village	8.2	7.9	in 2005	29	6.9
Tarraleah Village	6.1	5.8	in 2010	27	4.1
Lake St Clair National Park	4.7	4.4	in 2010	21	2.8

Highest April mean daily minimum temperature for at least 20 years
	Mean daily minimum temperature for April 2012 (°C)	Most recent April at least this warm		Years since warmer	Average for April
Lake Leake (Elizabeth River)	5.5	5.7	in 1990	22	4.2

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Highest April mean temperature for at least 20 years
	Mean daily temperature for April 2012 (°C)	Most recent April at least this warm		Years since warmer	Average for April
Cape Sorell	14.8	14.9	in 1939*	32	12.8
Cape Bruny Lighthouse	14.3	14.4	in 1989	23	12.5
Maatsuyker Island Lighthouse	13.3	14.2	in 1989	23	12.0

* note: there are gaps in the historical record at this site, so it is possible a higher value has gone unreported.

Extremes Maps Records Summaries Important notes the top

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Summary statistics for April 2012
	Maximum temperatures for April (°C)				Minimum temperatures for April (°C)				Rainfall for April (millimetres)
	Mean for April 2012	Diff from average	Highest for April 2012		Mean for April 2012	Diff from average	Lowest for April 2012		Total for April 2012	Average for April	Rank of April 2012	Fraction of April average
Northern (district 91)
Bridport (Sea View Villas)	18.7	+0.6	23.8	3rd	10.2	+0.7	2.4	29th	53.5	62.1	average	86%
Burnie (Round Hill)	19.1	+1.4	23.4	3rd	11.2	+1.2	3.8	10th	52.6	74.6	average	71%
Cape Grim	16.8		21.5	5th	12.4		6.8	10th	78.8
Cape Grim BAPS (Comparison)	17.2	+0.8	22.3	5th	12.4	+1.0	6.8	10th	85.4	68.2	average	125%
Cressy Research Station	19.2	+1.0	24.6	3rd	6.3	+0.7	-2.4	30th	44.2	45.3	average	98%
Devonport Airport	18.6	+1.0	21.7	18th	9.1	+0.4	2.0	10th	30.4	61.3	low	50%
Launceston (Ti Tree Bend)	19.6	+0.8	24.5	5th	8.2	+0.7	0.3	10th	37.8	53.1	average	71%
Launceston Airport	19.2		24.6	5th	7.2		-0.6	10th	34.0
Low Head	18.3	+0.7	21.6	5th	12.0	+0.9	6.4	30th	42.6	57.5	average	74%
Luncheon Hill (Forestry)	16.4	+0.8	23.6	5th	9.1	+1.0	2.6	10th	109.6	104.0	average	105%
Marrawah	17.6	+0.8	24.0	5th	11.5	+1.2	6.0	10th	98.6	85.7	average	115%
Scottsdale (West Minstone Road)	18.1	+0.1	24.0	5th	8.1	+0.2	0.8	29th	54.0	80.9	average	67%
Sheffield School Farm	16.9	+0.4	22.4	5th	7.2	+0.2	0.0	10th	99.8	66.5	high	150%
Smithton Aerodrome	18.5	+0.8	22.2	4th	7.8	0.0	1.2	10th	66.2	59.4	average	111%
Wynyard Airport	18.8	+1.4	23.3	3rd	7.8	+0.7	0.2	10th	46.8	73.8	average	63%
East Coast (district 92)
Bicheno (Council Depot)	19.3	+0.5	26.5	15th	11.0	+0.7	4.5	30th	39.6	59.9	average	66%
Eddystone Point	19.7	+1.6	25.7	5th	11.8	+0.3	3.7	10th
Fingal (Legge Street)	19.3	+1.0	27.1	4th	5.4	-0.1	-3.8	30th	40.8	52.0	average	78%
Friendly Beaches	19.4	+0.8	25.9	15th	10.7	+1.0	2.4	30th	70.2	54.4	average	129%
Lake Leake (Elizabeth River)	15.3	+1.2	22.9	5th	5.5	+1.3	-3.0	30th	43.0	69.5	average	62%
Maria Island (Point Lesueur)	18.9		25.1	5th	12.0		5.8	10th	41.6
Orford (Aubin Court)			26.4	6th	8.9	+0.5	2.4	29th	50.6	58.1	average	87%
Scamander	19.3	+0.5	26.6	4th	10.1	+0.3	3.2	30th	36.6	69.0	average	53%
St Helens Aerodrome	19.3	+1.0	25.4	3rd	10.1	+0.5	2.9	30th	32.0	61.1	low	52%
Swan Island	18.6	+0.4	21.9	5th	13.3	+0.5	6.5	10th	38.4	50.3	average	76%
Swansea (Francis Street)	19.5		26.5	15th	9.2		1.0	30th	42.4
Midlands (district 93)
Ross (The Boulevards)	18.8	+1.3	24.6	3rd	6.0	+0.3	-4.3	30th	24.4	37.3	low	65%
Southeast (district 94)
Bull Bay (Lauriston)	18.5	+1.3	25.0	6th	10.4	+0.9	5.4	10th	33.8	48.1	average	70%
Campania (Kincora)	20.2	+1.4	28.3	6th	7.7	+0.4	-0.6	30th	16.6	37.4	low	44%
Cape Bruny (Cape Bruny)	17.5	+1.2	24.7	5th	11.1	+1.3	5.0	9th	87.4	55.2	high	158%
Cape Bruny Lighthouse	17.1	+1.6	23.8	5th	11.2	+1.6	5.2	9th	88.8	80.0	average	111%
Dover	18.0	+1.3	25.0	4th	7.9	+0.8	1.0	30th	76.8	67.5	high	114%
Dunalley (Stroud Point)	19.1		25.9	5th	11.5		5.7	30th	19.2
Geeveston (Cemetery Road)	17.9	+0.7	26.2	5th	7.6	+1.3	-0.4	30th	95.4	65.0	high	147%
Grove (Research Station)	18.7		26.8	5th	5.9		-1.8	30th	61.4
Hobart (Ellerslie Road)	19.6	+2.3	28.9	5th	10.4	+1.5	4.0	30th	22.0	51.4	low	43%
Hobart Airport	19.8	+1.7	27.5	5th	9.2	+0.4	2.5	30th	14.0	43.0	low	33%
Maatsuyker Island Lighthouse	15.8	+1.3	24.3	19th	10.9	+1.4	5.2	9th	206.0	108.9	v high	189%
Melton Mowbray (North Stockman)	18.4	+1.2	26.4	6th	7.1	+1.4	0.4	30th	20.2	30.0	average	67%
Mount Wellington	9.7	+1.3	18.0	5th	3.4	+1.2	-3.1	9th
Tasman Island	16.0	+1.2	23.9	5th	10.7	+1.0	3.9	10th	73.4	70.4	average	104%
Tunnack Fire Station	16.9	+1.7	23.6	6th	6.6	+1.4	-3.2	30th
Derwent Valley (district 95)
Bushy Park (Bushy Park Estates)	19.4	+1.5	28.1	5th	6.2	0.0	-0.8	30th	38.2	46.5	average	82%
Maydena Post Office	16.3	+0.4	25.0	6th	7.1	+1.7	1.5	10th	95.6	83.5	high	114%
Ouse Fire Station	19.1	+0.8	29.1	5th	6.2	+1.4	-0.6	30th	42.4	31.7	high	134%
Tarraleah Village	13.8	-0.1	22.3	6th	5.8	+1.7	-0.9	30th	89.9	95.0	average	95%
Central Plateau (district 96)
Butlers Gorge	13.9	+0.9	22.0	6th	5.3	+2.0	-1.8	2nd	108.6	144.5	average	75%
Lake St Clair National Park	13.6	+0.6	22.1	5th	4.7	+1.9	-1.7	30th	143.4	135.4	average	106%
Liawenee	12.7	+0.5	21.7	5th	3.1	+1.5	-4.2	30th	71.0	73.3	average	97%
West Coast (district 97)
Cape Sorell	17.6	+2.2	22.8	6th	12.0	+1.7	7.0	10th	99.8	110.0	average	91%
Hartz Mountain (Keoghs Pimple)	11.8	+0.8	19.9	6th	5.8	+1.4	-0.6	9th
Low Rocky Point	17.3		28.1	6th	11.2		6.8	9th	141.6	111.5	high	127%
Mount Read	9.5	+0.6	17.4	6th	4.3	+1.0	-1.9	9th
Scotts Peak Dam	15.9	+1.3	24.2	6th	8.1	+1.5	1.7	9th	153.0	127.3	high	120%
Strahan Aerodrome	18.1	+1.5	27.2	6th	9.5	+1.1	4.3	10th	133.2	114.2	average	117%
Strathgordon Village	15.1	+0.9	22.9	5th	8.2	+1.3	2.0	9th	196.6	201.5	average	98%
Warra	14.5		21.9	5th	6.8		0.7	9th	168.2
King Island (district 98)
King Island Airport	18.6	+1.0	27.5	6th	11.2	+0.7	5.9	16th	66.0	57.2	high	115%
Flinders Island (district 99)
Flinders Island Airport	19.4	+0.7	24.5	3rd	11.7	+1.0	1.8	10th	38.4	59.2	average	65%
Antarctica and Macquarie Island (district 300)
Macquarie Island	7.8	+0.9	9.9	20th	4.9	+1.2	-1.8	30th	87.8	93.1	average	94%

Extremes Maps Records Summaries Important notes the top

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