Friday, 1 July 2011 - Monthly Climate Summary for Melbourne Metropolitan Area and Environs - Product code IDCKGC1xx0

Melbourne Metropolitan Area and Environs in June 2011: Rainfall less than that in most years

Highlights:

• Overnight temperatures near to those in most years
• Daytime temperatures slightly warmer than those in most years
• Rainfall less than that in most years

Details Extremes Records Summaries Important notes the top

Melbourne City

Located in the Central District at the head of Port Phillip Bay, Melbourne is Victoria's State Capital. Here, overnight minimum temperatures were slightly warmer than those usually experienced and averaged 7.8°C (departure from normal 0.9°C). That the overnight temperatures in Melbourne are higher than those in most surrounding localities is a consequence of the city being under the influence of the effect of urbanisation (cities are usually warmer than their rural surroundings, especially at night, because of heat stored in bricks and concrete and trapped between close-packed buildings). Daytime maximum temperatures were much warmer than those usually experienced and averaged 15.8°C (departure from normal 1.8°C). Total rainfall for the month was 32.2 mm, this being slightly less than that usually recorded (normal 49.0 mm, percentage of normal received 66%).

Suburbs

In the suburb of Essendon, which is located some 15 kilometres to the northwest of the city centre, overnight minimum temperatures were near to those usually experienced and averaged 6.1°C (departure from normal 0.2°C). Daytime maximum temperatures were warmer than those usually experienced and averaged 14.7°C (departure from normal 1.1°C). Total rainfall for the month was 23 mm, this being less than that usually recorded (normal 38.8 mm, percentage of normal received 59%).

The suburb of Laverton is located some 30 kilometres to the southwest of the city centre, and is often under the drying influence of the rain shadow from the ranges of western Victoria. Here, overnight minimum temperatures were near to those usually experienced and averaged 5.5°C (departure from normal -0.3°C). Daytime maximum temperatures were slightly warmer than those usually experienced and averaged 14.9°C (departure from normal 0.7°C). Total rainfall for the month was 24.2 mm, this being less than that usually recorded (normal 37.8 mm, percentage of normal received 64%).

In the suburb of Bundoora, which is located some 20 kilometres to the northeast of the city centre, overnight minimum temperatures were near to those usually experienced and averaged 5.9°C (departure from normal -0.2°C). Daytime maximum temperatures were slightly warmer than those usually experienced and averaged 14.5°C (departure from normal 0.6°C). Total rainfall for the month was 38.3 mm, this being slightly less than that usually recorded (normal 55.2 mm, percentage of normal received 69%).

In the suburb of Moorabbin, which is located some 20 kilometres to the southeast of the city centre, overnight minimum temperatures were near to those usually experienced and averaged 6.3°C (departure from normal -0.4°C). Daytime maximum temperatures were slightly warmer than those usually experienced and averaged 14.9°C (departure from normal 0.7°C). Total rainfall for the month was 38 mm, this being slightly less than that usually recorded (normal 55.4 mm, percentage of normal received 68%).

Some 20 kilometres northwest of the Melbourne city centre, and located in a somewhat rural setting, Melbourne Airport, is typical of the Central District. Here, overnight minimum temperatures were near to those usually experienced and averaged 6.2°C (departure from normal 0°C). Daytime maximum temperatures were warmer than those usually experienced and averaged 14.6°C (departure from normal 1°C). Total rainfall for the month was 19.8 mm, this being less than that usually recorded (normal 37.3 mm, percentage of normal received 52%).

Drivers

The powerful La Niña event of the past year or so has finally ended, and sea surface temperatures across the tropical Pacific Ocean have largely returned to normal (bringing an exceptionally wet period to a conclusion). The Southern Oscillation Index, which had been strongly positive during the La Niña event, is now also close to normal (zero). However, sea surface temperatures across waters to the south of the continent are mostly slightly above normal.

The pressure patterns during June were driven by a combination of strong high pressure systems over west Indian Ocean high latitudes and a trough of low pressure over Australian longitudes. This resulted in a series of fast moving frontal systems amplifying as they approached Western Australia, and then weakening before passing across southeastern Australia - hence, these were mostly not accompanied by very much rain falling in Victoria (but several of them retained sufficient strength to be associated with strong northerly winds ahead of their passage).

Details Extremes Records Summaries Important notes the top

Details Extremes Records Summaries Important notes the top

Details Extremes Records Summaries Important notes the top