The Gauteng Weather and Storm Warning Thread!

Geoff.D

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Rained pretty hard from 17:15 onwards to about 19:00, thereafter gentle soft rain until about 20:30. Did not venture out to see how much. Will see tomorrow morning!
The TS predictions seem to have been the most accurate of all the possible predictions.
Have a few sat pictures from about 17:15 to 19:00. Not sure I can post them though, as I dont have the info first hand.
Pretty sure we have already reached the average rainfall for January in the first 8 days of the month.
 
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Geoff.D

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Die Wilgers

2017-10-31 Oct Summary 73 mm
2018-11-30 Nov Summary 42.5 mm
2018-12-31 Dec Summary 35.5 mm
2019-01-01 07:00 55 mm
2019-01-02 07:00 16 mm
2019-01-03 07:00 05 mm
2019-01-06 07:00 2.5 mm
2019-01-07 07:00 6.5 mm
2019-01-08 07:00 24 mm
 

Cius

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Can anyone explain why all this rain is not increasing the Vaal levels:


From here: http://www.reservoir.co.za/

I assume they are letting the additional water pass through to full up downstream dams first that have less evaporation or something?
 

Sinbad

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Can anyone explain why all this rain is not increasing the Vaal levels:


From here: http://www.reservoir.co.za/

I assume they are letting the additional water pass through to full up downstream dams first that have less evaporation or something?
Rain in Gauteng does not run into the vaal dam, it runs into the Barrage, which is why you see the outflow figures spiking.
 

Cius

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Rain in Gauteng does not run into the vaal dam, it runs into the Barrage, which is why you see the outflow figures spiking.
I was under the impression that most Gauteng rain flows North to Harties, but I thought the recent rainfall also fell to the south over the Vaal Catchment.

What exactly is the Barrage outflow and how does it differ from the normal Vaal outflow on that graph?
 

Sinbad

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I was under the impression that most Gauteng rain flows North to Harties, but I thought the recent rainfall also fell to the south over the Vaal Catchment.

What exactly is the Barrage outflow and how does it differ from the normal Vaal outflow on that graph?
South of the watershed (witwatersrand) it flows into the vaal river system below the Dam. North of the watershed it's Harties.
Barrage is a separate dam below the Vaal dam. The outflow is how much water they're releasing from the Barrage. Vaal dam outflow flows into the Barrage reservoir, along with most of the rain south of the Rand. Main catchment of the Vaal Dam is Mpumalanga/freestate - Harrismith/Fouriesberg and surrounds.
 

Geoff.D

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Rains north of the WWR, flow into a number of dams including Hartie's, Bon Accord, Rietvlei, and Roodeplaat. There are a few more dams also. Those dams have all maintained their levels or shown a small decline in levels. These rains we have had should see a small increase in the levels of some of those dams. This s good news for North West in the main because the outflows could be increased to top up other dams downstream from the main ones mentioned.
 
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Geoff.D

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This morning, listening to the weather forecast on TV, having to turn up the volume to hear what is being said because of a really heavy thunderstorm outside and being told that Gauteng would only have isolated storms later in the afternoon was hugely entertaining. We even had to switch on the lights, it was so dark.
Then looking at the Aviation satellite images, the TAFs and the TS probability map, which confirmed what was going on outside even more so.
And then towards the end of the morning news show, the weather guy abandoned his script and his pictures, changed the probabilities from 30% to 60%.
Long overdue that the TV stations start to stop using the predictions prepared the day before on rote and do a last minute update before they make such fools out of themselves.
 
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Toxxyc

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Was really dark and thundering with a plenty of drops here in Fourways an hour ago. Now it's clear skies, not a single cloud in sight.
 
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