Flooding, lightning and Heavy Rains 07-11-05 to 10-11-05 page 1

Previous Page

The Front

This is a 2 page report. Scroll to the bottom for the Link to page 2.

A trough, an upper low, lots of moisture - perfect! But what would it bring. Lightning, rain, wind? What followed would go down in the record books as one amazing system. Lets start at the beginning with the synoptic and satellite from the evening of the Saturday 5th

Later that evening saw lightning fire up on the west coast in the Ceduna area. Expectation of the show moving to the central districts was high. Progged to arrive in the early hours of Sunday the 6th I awoke early with camera all charged and ready to go.

But all was not going to plan. The system had stalled! Not going to be any light show for us tonight. Bugger. By sunrise Sunday morning - it became obvious that instability along the eastern edge of the upper low was going to peak east of the ranges. Sure enough at 10:00am the first echoes began near Murray Bridge. Strengthening to decent rain cores and drifting to the SW I decided it was time to go for a quick drive towards the lakes to check out these cells. Above: radar snippet from the morning of the 6th. Left: GPATS scan from early morning 6th

The bases were quite high and the sky was covered in a thin cirrostratus layer which inhibited decent vertical development. Even so considerable instability backbuilding in a line from the Murray Mouth to Murray Bridge dropped out some pretty solid rain shafts. Development was very fast and heavy and sporadic showers popped up out of nowhere, dumped then disappeared where I was near Woodchester. A few cloud to ground strikes were visible over the lakes and low rumbles of thunder with reasonable frequency suggested more lightning in the cloud. A few images of these cells can be seen in the photo album of the event.

Meanwhile to the north the sky was getting darker and looking more threatening. A rain band was forming. I headed home to check out the progress of the system.

Cells were popping up all over the place east of the ranges and an ever increasing band of rain was gaining strength. Yorke Peninsula, The mid North and Flinders districts were getting some pretty decent rain. Falls of 20mm were already accumulating near Coulta on the Eyre Peninsula! But it was moving ever so slowly. The wait for its arrival was painful! In the north the lightning was going crazy as can be seen from the animated snippet (image below right) from GPATS from 4:15pm to 6:30pm on the 6th. The associated radar image (below left) is quite telling also.

GPATS loop - above image 512 Radar scan crop from same time -left

The band slowly approached the city and ranges, gave a few rumbles and about 2.5mm of rain and that was seemingly it. What a disappointment. But it pays to keep an eye on the sky and about 8:30pm I noticed some flashes on the horizon. Off to the hilltop and a line of cells had redeveloped from the mid north down through the top of Yorke Peninsula and down the eastern coast of yorkes to the tip. For 2 hours I watched flashes grading from every 30 seconds or so to every few minutes. It never moved any closer for all this time and even with the 300mm lens on it was too far away to be truly photogenic. I did snap a few pics which highlight structure more than anything. These can be can be seen in the photo album. Finally it started to spit and I came down from the viewing point on my hill. What really caught my eye was a flash to my ENE. What the? A check on the radar proved most interesting.

An intense line, possibly a sqall line/ guster had developed along the eastern flanks of the ranges travelling in a SW direction. This was responsible for the new flashes of lightning I saw. It is an impresive line indeed! Before long the rain started to fall making photography difficult. I decided to sit this one out. Disappointingly it fell apart pretty quickly as it climbed the ranges and by the time it reached me at Meadows it was just light rain. The light show also disapaited significantly. At about 2:30am one almighty thunderclap shook the whole house and 2 more strikes VERY close shot down. Impossible to photograph with the rain and now fog/low cloud, but the thunder was impressive. That bolt must have been within a 100 metres of the house I would say!         Left: Radar image of the squall line.

 

By the morning considerably more rain than the 2.5mm earlier had fallen and 23mm was in the gauge. More fell across the northern ranges under the squall line. In the far north Pt Augusta had localised flooding from a 19.6mm in 55 minutes. Broken Hill was hit by a suspected Tornado. Wallaroo also had some flooding problems and Stenhouse Bay recorded an amazing 70mm!! Cape Borda's rainfall ( 81mm from the AWS, 74 from the manual gauge) is their highest daily rainfall since March 1877 (93.7mm then) and their second-highest on record (as well as being a November record!). Crops near Kadina on Yorke Peninsula suffered sever damage with 3cm hail. There were certainly some pretty good and widespread falls and severe storm damage about. The daily rain bulletin for SA can be seen below.

MOVE ON TO NEXT PAGE