The Queen's Birthday East Coast Low: 8 - 9 June 2007

• Summary of Events
• Satellite Images
• Weather charts:
  • Surface
  • Upper Air: 700hPa | 200 hPa | Aerological Diagram
• Observations:
  • Surface Pressure
  • Wind
  • Waves
  • Rainfall: Radar | Observations | Flood Predictions
• Impact summaries are provided in the June Climate Summaries for NSW and Sydney.

Photo: Belmore Bridge Maitland, courtesy NSW State Emergency Service.

Summary of Events

The first of the June 2007 East Coast Lows (ECL) occurred over Friday 8 and Saturday 9 June.  The event caused widespread damage in the coastal parts of the Hunter, Central Coast and Sydney Metropolitan areas, resulting from sustained heavy rain, strong winds and large ocean waves and swell. There were nine fatalities associated with the storm and nearly 20,000 calls for assistance made to the State Emergency Service. 

The Queen’s Birthday ECL developed in a pre-existing trough of low pressure over the northern Tasman Sea. This trough was directing a humid northeast to southeast air stream across northeast NSW and there was a weak low analysed just off the coast near Coffs Harbour on Thursday morning.  The low moved south along the NSW coast, before moving out into the Tasman Sea on Monday 10 June 2007. Several factors influenced the development of this low including:

• During Friday and Saturday, a high pressure system moved through Bass Strait from the Bight and strengthened over the southern Tasman deepening the humid easterly flow over eastern NSW.
• An upper cold pool and associated north westerly jet stream moved across the north of the state reaching the coast on Friday.
• There were warmer than average (about 1 degree) sea surface temperatures off the coast with the strongest east to west gradient directly offshore from Newcastle.

On Thursday night the low deepened to 1009hPa just north of Newcastle. Gale force south easterly winds started about midnight and continued for 12 hours. It was during this period that the Pasha Bulker ran aground at Nobbys Beach.  Around noon on Friday the low near the coast weakened and the winds eased, but from 3.30pm until 7.30pm a persistent line of thunderstorms over Newcastle and northern parts of Lake Macquarie caused flash flooding.

A second small-scale low formed late on Friday evening and crossed the coast right over Newcastle in the early hours of Saturday morning, again bringing gale to storm force winds and the strongest observed wind gusts (135 km/h at Norah Head and 124 km/h at Newcastle). The lowest pressure officially recorded was 994hPa at Williamtown and the minimum central pressure of the low was estimated to be 990 hPa. The record wave height recorded at Sydney Waverider Buoy of 14.13m at 2am Saturday was the highest recorded since records began in 1992. The low weakened as it moved inland, but a line of heavy showers and thunderstorms moved to the south bringing heavy rain along the Central Coast before weakening over northern suburbs of Sydney during Saturday morning.

Most of the rainfall from this event fell during Friday 8 June in the Hunter and Metropolitan Districts. However, significant falls were received throughout the period from the 6 – 10 June. The ensuing Hunter flood was the largest since 1971 at the major cities of Singleton and Maitland. At Maitland, where the peak occurred on 11 June, the Bureau's flood warnings acted as a trigger for the SES to evacuate some 4000 people from the CBD and Lorne as a precautionary measure in case the levees overtopped or failed. 

Satellite Images

High resolution infrared satellite image: 0:30am Saturday 9 June 2007.

Satellite Loop: The full satellite loop runs from 2:30 pm EST Thursay 7 to 10:30pm EST Saturday 9 June This loop contains 57 (~55 kB) images and may take some time to load!

Surface Charts

Click on the chart to see the development of the system from 10pm 7 June to 10pm (EST) 9 June 2007.

700 hPa Temperature Contours 10pm Friday 8 June 2007

200 hPa Height and Wind Speed Contours: 10pm Friday 8 June

Observations from weather balloon launched from Williamtown at 10am 8 June 2007

Vertical profiles of temperature, dewpoint and wind. See Sports Aviation for help on interpreting this aerological diagram.

Sea Surface Temperature analysis: 9 June 2007

Surface Pressure

Wind

Waves

Wave data provided by NSW Department of Commerce's Manly Hydraulics Laboratory on behalf of  NSW Department of Environment and Climate Change.

Radar Images:

Radar image at 1:10am Saturday 9 June 2007 as the low was crossing the coast.

Radar Loop: The loop runs from 3:00 pm EST Friday 8 to 9:00 am EST Saturday 9 June 2007. These high resolution images are from the Newcastle radar, located at Lemon Tree Passage. This loop contains 109 (~50kB) images and may take some time to load!

Rainfall:

Rainfall Totals: 5 - 11 June 2007

Bureau stations receiving more than 400mm of rainfall from 9am 6 June to 9am 10 June.

Flood Prediction

The Hunter Flood was the largest since 1971 at the major cities of Singleton and Maitland. At Maitland, where the peak occurred on 11 June.