Tasmania in April 2011: Wet continues in the east

It was another wet month in the east of Tasmania after very heavy falls between the 10th and 13th. In the west it was drier than usual, despite cold fronts that brought some rain. Temperatures were were mostly slightly warmer than usual, but neither extremely hot nor extremely cold.

  • 153 mm in a day and 57 mm in an hour at Eddystone Point
  • Wettest April day on record in parts of the southeast
  • Hobart's wettest day in over 50 years

Extreme rainfall in the east

Heavy rain fell in eastern Tasmania between the 10th and 13th as an active and complex low pressure system moved nearby, bringing the fourth heavy rain event to the state for the year. The heaviest rain fell in the far northeast overnight on the 10-11th, with Eddystone Point receiving 57 mm in the hour around midnight and 153 mm in the 24 hours to 9 am on the 11th. Rainfall of this intensity is expected to occur less than once every 100 years in this region.

The heaviest rain moved slowly southwards, affecting the area around St Helens on the 11th and 12th (with the airport receiving 176 mm in 2 days) and the southeast of Tasmania from the afternoon of the 12th until the morning of the 13th. Hastings Chalet (125 mm), Mount Nelson (124 mm), Leslie Vale (112 mm) and Kingston (107 mm) were some of the sites in the southeast that had over 100 mm in a day, and several sites had their wettest April day on record.

Although not as damaging as the events in January or March, the rain did cause local flash flooding and minor to moderate flooding of some rivers.

Very wet in the east but drier than usual in the west

Heavy rain between the 10th and 13th ensured it was a very wet April in eastern Tasmania with many sites having at least double their April average. Eddystone Point (268 mm) and Gladstone (247 mm) reported the most rain for the month, both having their second-wettest April on record. They also had their wettest April in over 20 years along with Bicheno, Huonville and Scamander.

The west was drier than usual despite cold fronts bringing light to moderate falls between the 1st and 4th and again from the 19th to 24th. Zeehan (99 mm) had only half of its normal April rainfall. Still, most areas reported over 50 mm except for the Derwent Valley between New Norfolk and Ouse, and the Midlands around Campbell Town and Cressy. Ouse was the driest site with a total of 27.6 mm for the month.

The heavy rain in the east added to record falls during January and March (and local heavy falls in February) to give some sites, particularly in the northeast, their wettest start to a year on record. North-eastern Tasmania has already had a much wetter than usual autumn, and Gladstone (511 mm) and Pyengana (589 mm) have already had their wettest autumn on record although there is still a month to go.

Temperatures mostly near normal

There were no great extremes of temperatures during April: most days and nights were not too far from normal. Averaged over the month, minimum temperatures were just slightly warmer than usual, while maximum temperatures were warmer than usual in the west but cooler than usual in the east.

The warmest days occurred between the 5th and 9th as northerly winds blew over the state, pushing Bushy Park's temperature up to 26.5 °C on the 8th. The coolest days for the month followed between the 11th and 15th as rain fell in a southeast to southerly airstream, but the coldest day overall was at Mount Wellington on the 22nd when it only reached 3.6 °C in snowy weather. 

Cool and warm nights were interspersed through the month. Cloud, rain and wind meant the morning of  the 9th was one of the warmest with several sites not falling below 15 °C. The minimum temperature at King Island on this morning was 16.6 °C. A week later, the morning of the 16th was one of the coldest with light winds and clear skies allowing Liawenee's temperature to dip to -4.7 °C.

Hobart's wettest day in 50 years and wettest April since 1996

Hobart had its wettest day in over 50 years when 78.8 mm fell in the 24 hours to 9 am on the 13th. The last time there was so much rain in a day was 23 April 1960. Another 44 mm was reported between the 10th and 15th, and combined with few millimetres on other days to give a monthly total of 125 mm. This was well above the average of 52 mm, and made it Hobart's wettest April since 1996. 

Temperatures in Hobart were warm between the 7th and 9th, with 3 days in a row over 23 °C suggesting a return to summer conditions. But a cold week followed, with no day warmer than 14.4 °C between the 11th and 15th, and a minimum of just 5.0 °C on the 16th. The last week of the month was warmer again with daytime temperatures around 20 °C. The average minimum and maximum temperatures for the month were 10.0 °C and 18.1 °C respectively, around a degree warmer than normal.

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Extremes in April 2011
Hottest day 26.5 °C at Bushy Park (Bushy Park Estates) on the 8th
Warmest days on average 19.1 °C at Eddystone Point
Coolest days on average 9.3 °C at Mount Wellington
Coldest day 3.6 °C at Mount Wellington on the 22nd
Coldest night -4.7 °C at Liawenee on the 16th
Coolest nights on average 2.2 °C at Liawenee
Warmest nights on average 13.0 °C at Hogan Island
Warmest night 16.6 °C at King Island Airport on the 9th
Warmest on average overall 15.4 °C at Hogan Island
Coolest on average overall 6.3 °C at Mount Wellington
Wettest overall 268.0 mm at Eddystone Point
Driest overall 27.6 mm at Ouse Fire Station
Wettest day 153.2 mm at Eddystone Point on the 11th
Highest wind gust 139 km/h at Macquarie Island on the 24th


Maps

Observed Anomaly Decile rank
Total
rainfall
Map of Rainfall totals Map of Percentage of normal rainfall Map of Rainfall deciles
Mean
daily
maximum
temperatures
Map of Mean maximum temperature Map of Anomaly in mean maximum temperature Map of Decile rank of mean maximum temperature
Mean
daily
minimum
temperatures
Map of Mean minimum temperature Map of Anomaly in mean minimum temperature Map of Decile rank of mean minimum temperature

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


Record highest April daily rainfall

Highest daily rainfall
in April 2011 (mm)
Previous wettest
for April
Years of
record
Taroona (Taroona Crescent) ** 97.2 on the 13th 39.0 on the 18th in 1996 48
Geeveston (Cemetery Road) 65.2 on the 13th 40.0 on the 2nd in 1996 40
Risdon Vale (Poplar Road) 88.4 on the 13th 55.9 on the 21st in 1965 32
Blackmans Bay Treatment Plant 92.2 on the 13th 50.8 on the 18th in 1996 30
Bull Bay (Lauriston) 75.0 on the 13th 52.0 on the 18th in 1996 28
Nugent (Twilight Valley) 80.6 on the 13th 76.4 on the 24th in 2001 28
Tea Tree (The Point) 74.4 on the 13th 52.2 on the 17th in 1996 25
Richmond (Strathayr) 55.2 on the 13th 47.0 on the 17th in 1996 23
** Taroona had its wettest day on record for any month of the year


Highest total April rainfall for at least 20 years

Total rainfall
for April 2011 (mm)
Most recent April
at least this wet
Years since
wetter
Average for
April
Gladstone (Old Post Office) 247.0 295.1 in 1929 70 73.9
Eddystone Point 268.0 308.7 in 1960 50 66.6
Bicheno (Council Depot) 151.4 192.5 in 1960 44 60.2
Huonville (Tutton Avenue) 96.2 160.2 in 1965 38 52.9
Scamander 172.4 439.2 in 1974 27 70.1




Record highest total January to April rainfall

Total rainfall
for January to April 2011 (mm)
Previous wettest
for January to April
Years of
record
Average for
January to April
Pioneer (Main Road) 705.3 540.7 in 1929 107 241.7
Eddystone Point 566.2 519.4 in 1946 100 218.7
Gladstone (Old Post Office) 776.0 605.0 in 1977 80 235.6
Devonport Airport 355.2 338.0 in 1973 47 185.9
Pyengana (Forest Lodge Road) 931.8 579.2 in 2004 46 333.6
Forthside Research Station 444.8 433.0 in 1989 45 228.1
Barrington Post Office 498.1 457.0 in 1989 44 257.1
Scottsdale (West Minstone Road) 421.8 371.4 in 1989 40 232.9
King Island Airport 315.0 275.8 in 1983 37 177.2
Scamander 842.7 360.8 in 2004 27 217.4
Cape Grim BAPS (Comparison) 300.4 278.4 in 1990 24 181.9
Deviot Jetty 366.4 316.8 in 1996 20 206.4



Summary statistics for April 2011

Maximum temperatures
for April
(°C)
Minimum temperatures
for April
(°C)
Rainfall
for April
(millimetres)
Mean for
April
2011
Diff
from
average
Highest for
April
2011
Mean for
April
2011
Diff
from
average
Lowest for
April
2011
Total for
April
2011
Average
for
April
Rank of
April
2011
Fraction of
April
average
Northern (district 91)
Bridport (Sea View Villas) 17.8 -0.3 20.8 9th 9.9 +0.5 6.0 16th 138.4 62.7 v high 221%
Burnie (Round Hill) 18.1 +0.4 20.5 4th 10.8 +0.8 8.2 2nd 62.6 74.9 average 84%
Cape Grim 16.4   20.1 8th 11.5   7.4 25th 60.8


Cape Grim BAPS (Comparison) 16.6 +0.2 20.4 8th 11.6 +0.2 8.3 25th 60.4 67.5 average 89%
Cressy Research Station 17.7 -0.5 22.1 9th 6.4 +0.9 -0.3 16th 49.2 45.4 average 108%
Devonport Airport 17.6 0.0 21.1 9th 9.5 +0.9 6.5 16th 77.2 61.9 high 125%
Launceston (Ti Tree Bend) 18.7 -0.1 22.9 9th 7.7 +0.2 2.6 16th 65.8 53.6 average 123%
Launceston Airport 17.8   23.7 9th 6.7   1.8 16th 55.4


Low Head 17.5 -0.1 20.7 9th 11.4 +0.4 8.1 16th 84.6 58.6 high 144%
Luncheon Hill (Forestry) 16.2 +0.7 21.4 6th 8.7 +0.7 5.2 25th 73.8 103.7 low 71%
Marrawah 17.0 +0.2 20.5 8th 10.7 +0.5 6.7 25th 50.4 85.4 low 59%
Scottsdale (West Minstone Road) 17.2 -0.8 21.2 9th 7.6 -0.4 3.6 21st 100.0 81.7 high 122%
Sheffield School Farm 16.3 -0.2 19.8 5th 7.3 +0.3 4.3 16th 51.2 64.1 low 80%
Smithton Aerodrome 17.8 +0.1 21.1 8th 8.3 +0.6 1.3 25th 46.8 58.9 average 79%
Wynyard Airport 17.9 +0.5 20.6 9th 7.6 +0.5 3.2 25th 67.8 74.4 average 91%
East Coast (district 92)
Bicheno (Council Depot) 18.1 -0.8 21.1 5th 10.6 +0.3 7.4 25th 151.4 60.2 v high 251%
Eddystone Point 19.1 +1.0 22.3 8th 11.5 0.0 7.9 2nd 268.0 66.6 v high 402%
Fingal (Legge Street) 17.9 -0.4 23.4 9th 6.1 +0.6 0.9 8th 67.0 52.0 high 129%
Friendly Beaches 18.0 -0.6 22.3 8th 10.2 +0.5 7.7 28th 128.6 53.3 high 241%
Lake Leake (Elizabeth River) 14.3 +0.2 20.1 9th 5.1 +1.0 1.2 29th 61.2 69.8 average 88%
Maria Island (Point Lesueur) 16.8   21.4 8th 11.4   8.9 25th 93.0


Orford (Aubin Court) 17.4 -1.0 25.0 8th 7.5 -0.9 2.2 21st 72.0 58.2 high 124%
Scamander 18.2 -0.6 22.8 19th 9.8 0.0 6.5 2nd 172.4 70.1 v high 246%
St Helens Aerodrome 18.1 -0.3 21.9 9th 9.7 +0.1 5.8 2nd 223.2 63.2 v high 353%
Swan Island 18.0   22.0 9th 12.6   10.0 2nd 96.4 51.5 high 187%
Swansea (Maria Street) 17.7   24.0 9th     3.8 29th 91.1


Midlands (district 93)
Ross (The Boulevards) 17.3 -0.2 23.1 9th 6.3 +0.7 0.7 16th 41.2 38.1 average 108%
Southeast (district 94)
Bull Bay (Lauriston) 17.1 -0.1 24.0 8th 9.7 +0.2 6.0 16th 108.0 48.6 v high 222%
Campania (Kincora) 18.4 -0.5 25.1 8th 8.4 +1.2 2.5 16th 95.2 39.2 v high 243%
Cape Bruny (Cape Bruny) 16.4 +0.1 23.7 8th 10.1 +0.3 6.6 25th 74.0 52.9 high 140%
Cape Bruny Lighthouse 15.9 +0.4 23.0 8th 10.1 +0.5 7.1 16th 76.6 79.9 average 96%
Dover 16.7 0.0 24.5 8th 7.3 +0.2 2.2 16th 117.6 67.4 v high 174%
Geeveston (Cemetery Road) 17.4 +0.2 25.6 8th 7.3 +1.1 0.5 25th 105.4 64.2 high 164%
Grove (Research Station) 17.6   24.9 8th 6.5   -0.1 25th 79.4


Hobart (Ellerslie Road) 18.1 +0.8 25.6 8th 10.0 +1.1 5.0 16th 125.2 51.6 v high 243%
Hobart Airport 18.0 -0.1 25.1 8th 9.8 +1.1 5.4 16th 86.0 43.5 v high 198%
Maatsuyker Island Lighthouse 14.6 +0.1 22.4 8th 10.2 +0.7 6.5 22nd 104.4 108.2 average 96%
Melton Mowbray (North Stockman) 17.0 -0.3 23.5 7th 6.4 +0.7 0.2 16th 61.4 30.6 v high 201%
Mount Wellington 9.3 +1.0 15.9 7th 3.3 +1.2 -1.1 2nd 235.0 88.8 v high 265%
Tasman Island 14.5   18.8 8th 9.9   7.0 24th 89.0 70.1 average 127%
Tunnack Fire Station 15.1 -0.1 20.0 7th 6.0 +0.9 -0.4 16th 108.2 46.4 v high 233%
Derwent Valley (district 95)
Bushy Park (Bushy Park Estates) 18.9 +1.0 26.5 8th 6.2 0.0 0.9 25th 29.8 46.5 low 64%
Maydena Post Office 16.5 +0.7 24.3 8th 5.8 +0.4 2.0 25th 50.4 82.9 low 61%
Ouse Fire Station 18.2 -0.1 25.3 8th 5.8 +1.1 0.3 16th 27.6 30.7 average 90%
Tarraleah Village 14.2 +0.3 21.6 7th 4.9 +0.8 -1.0 25th 83.8 95.1 average 88%
Central Plateau (district 96)
Butlers Gorge 13.7 +0.7 20.7 7th 3.5 +0.2 -1.6 8th 84.0 145.1 low 58%
Lake St Clair National Park 13.5 +0.5 19.9 7th 3.5 +0.8 -1.3 16th 100.2 135.0 low 74%
Liawenee 12.2 -0.1 18.4 26th 2.2 +0.7 -4.7 16th 38.4 73.4 low 52%
West Coast (district 97)
Hartz Mountain (Keoghs Pimple) 11.6 +0.7 20.4 8th 5.5 +1.2 1.3 25th 136.2 69.4 v high 196%
Mount Read 9.6 +0.8 16.5 27th 4.2 +0.9 0.7 22nd 239.0 277.8 average 86%
Scotts Peak Dam 15.4 +0.9 24.2 8th 7.2 +0.6 2.7 25th 118.4 125.4 average 94%
Strahan Aerodrome 17.4 +0.8 24.5 7th 8.6 +0.2 3.6 25th 71.4 111.8 low 64%
Strathgordon Village 14.8 +0.6 21.9 8th 6.8 -0.1 2.9 25th 121.0 201.6 low 60%
Warra 13.6   21.5 8th 5.9   0.1 25th 126.8


King Island (district 98)
King Island Airport 17.8 +0.2 22.7 8th 11.1 +0.7 5.2 16th 42.2 56.8 low 74%
Flinders Island (district 99)
Flinders Island Airport 18.3 -0.4 23.5 9th 9.9 -0.8 5.2 11th 66.8 59.4 average 112%
Hogan Island 17.9   23.2 9th 13.0   10.9 22nd 107.6


Antarctica and Macquarie Island (district 300)
Macquarie Island 6.9 0.0 9.1 28th 3.4 -0.3 0.2 11th 61.0 93.1 v low 66%


Notes

A Monthly Climate Summary is prepared to list the main features of the weather in Tasmania using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at 9 am on Monday 2 May 2011. 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 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

Media
(03) 9669 4057
Enquiries