Severe Thunderstorms in Melbourne 6 March 2010

Event Summary

A developing low pressure system with an associated low pressure trough to the west of Victoria (refer Figure 1) combined with low level moisture and upper level forcing to generate showers and thunderstorms in the west of the State during the morning which spread eastward and intensified during the early afternoon. Severe thunderstorms developed to the northwest of the Melbourne Metropolitan Area and moved through the city from early afternoon progressing to the eastern suburbs and then into West Gippsland later in the afternoon.

Radar loop of the event

	Radar reflectivity images from the Melbourne radar (Laverton) 03:00 UTC (2:00pm EDT) to 04:54 UTC (3:54pm EDT) on 6 March.
Selected radar images
	Radar reflectivity image from the Melbourne radar (Laverton) at 03:00 UTC (2pm EDT) on 6 March.
	Radar reflectivity image from the Melbourne radar (Laverton) at 03:48 UTC (2:48pm EDT) on 6 March.
	Radar reflectivity image from the Melbourne radar (Laverton) at 04:24 UTC (3:24pm EDT) on 6 March.

The severe thunderstorms were associated with large hail and heavy rain resulting in widespread flash flooding and water and hail damage to property. There were some isolated severe wind gusts with the thunderstorms.

Rainfall totals in a 15 minute to 30 minute period included:

Hail:

10cm 3.30 pm Ferntree Gully,

Plenty of other reports of hail 2 to 4 cm hail from right across Melbourne.

Wind:

MSL Analysis of the event

Figure 1: MSL Analysis 11am March 6 2010

Satellite image of the event

Image from Aqua/MODIS satellite courtesy of NASA at 03:52 UTC (2:52pm EDT) on 6 March.

Examples of some of the Severe Thunderstorm Warnings issued during the event.

Australian Government Bureau of Meteorology
Victoria Regional Office

TOP PRIORITY FOR IMMEDIATE BROADCAST

SEVERE THUNDERSTORM WARNING

for DAMAGING WIND, FLASH FLOODING and LARGE HAILSTONES

For people in the North Central and parts of the Mallee, Northern Country, Wimmera, Western and Central Forecast Districts.

Issued at 12:36 pm Saturday, 6 March 2010.

Severe thunderstorms are likely to produce damaging winds, very heavy rainfall, flash flooding and large hailstones in the warning area over the next several hours. Locations which may be affected include Mildura, Ballarat, Bendigo, Seymour, Maryborough, Geelong and Melbourne.

The State Emergency Service advises that people should:
* Keep clear of fallen power lines.
* secure any loose objects in the vicinity of your home.
* keep away from creeks and drains.
* do not drive vehicles through flooded areas.
* stay indoors if possible.
* Avoid using the phone during the storm.
* if you are outside, avoid sheltering under trees
* listen to the radio for storm updates
* switch off your computer and electrical appliances

The next warning is due to be issued by 3:40 pm.

If severe thunderstorms develop in the Melbourne Area, a more detailed Severe Thunderstorm Warning will be issued to people in this area.

Warnings are also available through TV and Radio broadcasts, the Bureau's website at www.bom.gov.au or call 1300 659 217. The Bureau and State Emergency Service would appreciate warnings being broadcast regularly.

TOP PRIORITY FOR IMMEDIATE BROADCAST

SEVERE THUNDERSTORM WARNING - MELBOURNE AREA

for DAMAGING WIND, FLASH FLOODING and LARGE HAILSTONES

For people in the Western, Geelong and Bellarine Peninsula and parts of the Inner, Northern and Port Phillip Local Warning Areas.

Issued at 1:25 pm Saturday, 6 March 2010.

The Bureau of Meteorology warns that, at 1:20 pm, severe thunderstorms were detected on weather radar near Daylesford and the area west of Ballan. These thunderstorms are moving towards the southeast. They are forecast to affect Bacchus Marsh, Brisbane Ranges and the area west of Lara by 1:50 pm and Geelong City, Melton and Werribee by 2:20 pm.

Damaging winds, very heavy rainfall, flash flooding and large hailstones are likely.

The State Emergency Service advises that people should:
* Keep clear of fallen power lines.
* secure any loose objects in the vicinity of your home.
* keep away from creeks and drains.
* do not drive vehicles through flooded areas.
* stay indoors if possible.
* Avoid using the phone during the storm.
* if you are outside, avoid sheltering under trees
* listen to the radio for storm updates
* switch off your computer and electrical appliances

The next warning is due to be issued by 2:25 pm.

A more general severe thunderstorm warning is also current for the North Central and parts of the Mallee, Northern Country, Wimmera, Western and Central districts.

Warnings are also available through TV and Radio broadcasts, the Bureau's website at www.bom.gov.au or call 1300 659 217. The Bureau and State Emergency Service would appreciate warnings being broadcast regularly.

Australian Government Bureau of Meteorology
Victoria Regional Office

TOP PRIORITY FOR IMMEDIATE BROADCAST

SEVERE THUNDERSTORM WARNING - MELBOURNE AREA

for DAMAGING WIND, FLASH FLOODING and LARGE HAILSTONES

For people in the Inner, Western, Geelong and Bellarine Peninsula, Port Phillip and parts of the South East, Eastern, Northern and Mornington Peninsula Local Warning Areas.

Issued at 2:02 pm Saturday, 6 March 2010.

The Bureau of Meteorology warns that, at 1:55 pm, very dangerous thunderstorms were detected on weather radar near Gisborne and Melton. These thunderstorms are moving towards the southeast. Very dangerous thunderstorms are forecast to affect Footscray, St Albans, Sunbury and Werribee by 2:25 pm and Caulfield, Craigieburn, Glen Waverley, Greensborough, Melbourne City and Preston by 2:55 pm.

Damaging winds, very heavy rainfall, flash flooding and large hailstones are likely.

The State Emergency Service advises that people should:

The next warning is due to be issued by 3:05 pm.

A more general severe thunderstorm warning is also current for the North Central and parts of the Mallee, Northern Country, Wimmera, Western and Central districts.

Warnings are also available through TV and Radio broadcasts, the Bureau's website at www.bom.gov.au or call 1300 659 217. The Bureau and State Emergency Service would appreciate warnings being broadcast regularly.

Australian Government Bureau of Meteorology
Victoria Regional Office

TOP PRIORITY FOR IMMEDIATE BROADCAST

SEVERE THUNDERSTORM WARNING - MELBOURNE AREA

for DAMAGING WIND, FLASH FLOODING and LARGE HAILSTONES

For people in the Inner, South East, Eastern, Northern, Western, Port Phillip and parts of the Geelong and Bellarine Peninsula, Mornington Peninsula and Outer East Local Warning Areas.

Issued at 2:30 pm Saturday, 6 March 2010.

The Bureau of Meteorology warns that, at 2:25 pm, very dangerous thunderstorms were detected on weather radar near Melton, St Albans, Sunbury and Werribee. These thunderstorms are moving towards the southeast. Very dangerous thunderstorms are forecast to affect Caulfield, Craigieburn, Footscray, Glen Waverley, Greensborough, Melbourne City and Preston by 2:55 pm and Dandenong, Frankston, Ringwood and Scoresby by 3:25 pm.

Other severe thunderstorms were located near Ballan, the area south of Ballan, the area west of Gisborne and the area west of Woodend. They are forecast to affect Bacchus Marsh, Gisborne, the area west of Sunbury and the area west of Werribee by 2:55 pm and Whittlesea, the area south of Werribee, the area south of Whittlesea and the area west of Whittlesea by 3:25 pm.

Damaging winds, very heavy rainfall, flash flooding and large hailstones are likely.

Large hail has been reported at Melton from these thunderstorms.
Wind gusts to around 100 km/hr have been recorded at Melbourne Airport.

The State Emergency Service advises that people should:

The next warning is due to be issued by 3:30 pm.

A more general severe thunderstorm warning is also current for the Northern Country, North Central, Central and parts of the Mallee, Wimmera, West and South Gippsland and Western districts.

Warnings are also available through TV and Radio broadcasts, the Bureau's website at www.bom.gov.au or call 1300 659 217. The Bureau and State Emergency Service would appreciate warnings being broadcast regularly.

'The SES encourages community members to undertake simple measures to prepare for storms. More information on how to be StormSafe can be found on the SES website - www.ses.vic.gov.au'