WET WET WET 14-07-06 to 17-07-06

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The Beginning

 

A low with strong moisture infeeds from the tropics was progged to develop over central Australia/ northern SA border somewhere around the 13th July. It gave the possibilty of delivering some good falls over the pastoral areas. Late in the afternoon of the 13th the low spun up and a rain bearing system was born. (see image to the right). Good falls began to accumulate in the pastorals and the low began a very slow movement to the SE. As it centred over the Riverland the Mallee and river districts got a much deserved drink. Rainfalls statewide were patchy though with Adelaide and the Plains missing out mostly in this early stage. Southern Pastoral and Riverland areas got decent falls notably Renmark with 24mm to 8:30am and Paringa (private gauge) with 33mm to 9am on the 15th. Localised spots in the Mid North also accumulated good falls approaching 25mm, but this was not widespread with many areas needing good rains only receiving light falls. The Eyre Peninsula got generally good falls mostly exceeding 10mm.

Birth of the low over central Australia

 

The "real" WET!

The big surprise was what happened next. Well not so much a surprise that it happened, a surprise WHERE it happened. For the first time in many years here at my location was the place to be as the low "wrapped around" dragging cool moist air from the southern oceans and tropical air from the north with it. (see synoptic to the right) Starting to rain on the 14th it did not stop for 3 days and the totals accumulated to rather larger proportions. By the morning of the 15th I had 25.5mm in the gauge from the constant drizzle and rain. The moist ESE winds from the low bought VERY heavy fog with visibilty atround 10 metres (in spots) and cloaked the Eastern Ranges from Strathalbyn to the Bull Creek Range. West of this range the fog lifted and with it the moisture dropped away as the trend for the next few days was set. Falls east of this point were relatively insignificant. For example Kuitpo less than 10km had just 6mm. Adelaide plains were dry such was the strength of the rainshadow. Saturday the 15th dawned grey, damp and foggy........ RIGHT - synoptic BELOW - Typical Radar Image highlighting the rain shadow.

It certainly was far from over. The moist S-Easterlies had not lost anthing from the previous evening and kept up delivering a constant stream of rain and drizzle. All day on the 15th it kept this up when late in the evening a solid line of heay showers rocketed through delivering very heavy rain that peaked at nearly 30mm/ hour for a short period. This was the heaviest fall for the entire event. (see graph below) By Sunday morning (16th) another 28.8mm was in the gauge. And still it rained. All day Sunday the drizzle tending to rain continued to come. At an average rate of just 2.5mm/hour it certainly was not heavy. But it was persistant and did not give up. By the morning of Monday 17th an amazing 63.5mm was in the gauge! Incredible. This is the highest 24 hour fall I personally have recorded at this location. (**NB falls above 90mm have been recorded over 10 years ago by previous tenants in rare summer thunderstorms**) The rain shadow was still quite strong and again Adelaide and the Plains missed out with most falls there barely 5mm. The mositure pushed a lot further through the hills Sunday night than previously with 50mm falls at a few centres, notably Western Branch (woodside), Mt Barker and Nairne.

Late monday (17th) morning the rain finally stopped as high moved in to push away to low and the moisture with it. But a further 7mm had fallen before all was over.

This bought the total for the system to an incredible 124.8mm in less than 72 hours. The ground was saturated, the dam levels up a signifiacnt amount and local creeks and rivers were flowing nicely. Entirely unexpected, but entirely welcome was this system.

The Rain Graph.....

Below is a graph of the rainfalls as the weather station saw it. Notice how consistent the falls are. Pretty much non-stop for nearly 72 hours. (The accumulated daily line resets at midnight each day hence the graph "starting over".)

Images

Dams and creeks were flowing but not perhaps as hard as many may imagine after such huge falls. Steady soaking rains, dry soils and empty dams caught most of the runoff before it could cause any real problems. There were however some good scenes to be had.

CLICK FOR MAGES FROM THE EVENT

Just a sample for now..