Rain and storm for Cpt

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Geoff.D said:
The low pressure extending down from the north is very unusually, a narrow band down the west coast. But the long term for east models do not reflect any significant rainfall prospects for the next 8 to 10 days or so.
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As I pointed out previously, the low pressure area normally extending down from the tropics through Angola, Namibia, and into SA is way over to the west, so far over that is now almost entirely in a line down the west coast. I have not seen this pattern on the synoptic chart for many many months.

This means the band of moisture that leads to thunderstorms every afternoon has moved further westwards over the central parts of the country and deeper into the eastern cape. Whether it reaches all the way to the catchment areas for CTs major dams is not all that clear.
 
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We got quite a lot of water, I have a video of the hail, but have no idea how to post it.
 
ok now another 3 clouds over the dams. make it piss.

leave me alone it worked yesterday.
 
Cr419 said:
/snip

We got quite a lot of water, I have a video of the hail, but have no idea how to post it.
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You'd probably have to upload it to YouTube and then post the link.

As an aside, I see La Linea made an appearance in that second pic yesterday

BMgKwwT.gif
 
That's impressive hail by Cape Town standards. Last night reminded me a little of Gauteng summer. It even set my outside beam off in the middle of the night. Grrr!
 
[video=youtube;VnI9PJpeIl4]https://www.youtube.com/watch?v=VnI9PJpeIl4&feature=youtu.be[/video]
 
I did not believe this story when it was relayed to me, but seems to be true, although the details are a bit garbled and incomplete: https://www.news24.com/SouthAfrica/...ed-as-9-drown-in-western-cape-floods-20180214

Nine people drowned in flash floods in the Western Cape, the province's traffic chief said on Wednesday.

"In total nine people lost their lives in flooding in the Western Cape shortly after 12 o'clock," said Kenny Africa.

He said four women and a man drowned when they jumped out of their car to get away from a big mass of water advancing toward them on the High Noon pass, outside Villiersdorp, in the Caledon area.
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In another incident in the Montagu area four men, a driver and three passengers, died after they could not escape flood waters bearing down on them.

This incident also happened around 00:00.
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Sinbad said:
Villiersdorp... so would that be heading for Theewater?
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A single thunderstorm over a 500km^2 catchment isn't going to make a huge difference.

SAWS rainfall data for the 24 hours to 8am on Wed 14th: http://www.weathersa.co.za/media/data/climate/nr_daily_rai.pdf

Highest (in the W-Cape) include Hermanus 32mm, Robertson 16mm, Ceres 15mm, with others receiving much less. Also of note was Calvinia (NC) with 15mm.

Note that there are many locations which do not have official SAWS accredited rain guages.
 
I was on the rugby field for practice when that hail hit us. My head collected a few bumps. and my Jeep a few dents. damn.
Then the stormdrain in front of our complex got blocked and we had a temporary river past the front of my house bout 20cm deep down the road. A lott of water dropped in short time in Brackenfell.
 
Flarsiep said:
I was on the rugby field for practice when that hail hit us. My head collected a few bumps. and my Jeep a few dents. damn.
Then the stormdrain in front of our complex got blocked and we had a temporary river past the front of my house bout 20cm deep down the road. A lott of water dropped in short time in Brackenfell.
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You're a rugby player. This should be par for the course... Unless you're Naas Botha :p
 
Apart from a few insignificant weather fronts that are around in the next few days, the next minor front that will deliver a little bit of rain is only expected around Saturday the 24th.
This front will also miss cape town .
 
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Geoff.D said:
Apart from a few insignificant weather fronts that are around in the next few days, the next minor front that will deliver a little bit of rain is only expected around Saturday the 24th.
This front will also miss cape town .
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The front passing Cape Town on Sat 24th will actually develop into a cutoff-low, but this will form offshore, and have limited effects on land.

Several people have asked about cutoff-lows, and I am posting these charts as a brief ilustration of what can happen. In the upcoming event this particular scenario will almost certainly NOT happen, since this model run is from yesterday, and it has already been supersed by others which show a much weaker system.

The first feature to note, is something not shown on normal surface synoptic charts. It is a cold-core upper-trough, shown as a dotted red line (above the surface isobars). It is the 'driving force' of this system, and is responsible for the rapid deepening of the surface low, that develops into a 'cutoff' (different from normal) cold-front.

The second point is that the South Atlantic High Pressure is blocking the system, forcing it offshore, and preventing it from having much effect on land (and very little rain over CT). If events had developed differently, this kind of system could produce very heavy rain (50-100mm+) over land.

gfs_africa_180_1000_500_thick[20180226_0600_180Z_crop].gif

In the previous chart the rainfall shown is for the 3 hours from 3am to 6am on Mon 26th, when the system has already moved offshore.

The following chart shows the potential precipitation (unlikely to actually happen) during the 24 hours from 6am on Sun 25th to 6am on Mon 26th. The heaviest rainfall is always on the warm and humid side of the cutoff-low (oceanic and topical), which in the case of South Africa tends to have limited effects over the Cape interior.

gfs_africa_180_precip_p24[20180225_0600-25_0600_180Z_crop].gif

Note that the overall system is evolving (called https://en.wikipedia.org/wiki/Cyclogenesis#Extratropical_cyclones), starting as a cold-front, and developing into a cutoff-low. These charts are snapshots of particular stages of devleopment.
 
Geoff.D said:
Apart from a few insignificant weather fronts that are around in the next few days, the next minor front that will deliver a little bit of rain is only expected around Saturday the 24th.
This front will also miss cape town .
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Gordon will probably come in later. This system that started out as being only mildly interesting has changed quite a bit since first noticed a week ago. There is now a good chance of some rain in the mountains east of CT (~ 10mm or more), BUT PE is really in for a blasting and further eastwards up the coast, plenty of rain and high probability of flooding.
 
Geoff.D said:
Gordon will probably come in later. This system that started out as being only mildly interesting has changed quite a bit since first noticed a week ago. There is now a good chance of some rain in the mountains east of CT (~ 10mm or more), BUT PE is really in for a blasting and further eastwards up the coast, plenty of rain and high probability of flooding.
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All those who are not in the rain and in Pretoria East for a CPT topic and these are just about everyone on this forum, are NOT entitled to comment on this thread, as you don't know what happened, nor do you know what generally happens with regard to mistakes that the rain makers make which leads to errors on the precipitations.

Give the rain a break .........

https://mybroadband.co.za/vb/showth...phosa-Dead?p=21148079&viewfull=1#post21148079

;)
 
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f2wohf said:
All those who are not in the rain and in Pretoria East for a CPT topic and these are just about everyone on this forum, are NOT entitled to comment on this thread, as you don't know what happened, nor do you know what generally happens with regard to mistakes that the rain makers make which leads to errors on the precipitations.

Give the rain a break .........

https://mybroadband.co.za/vb/showth...phosa-Dead?p=21148079&viewfull=1#post21148079

;)
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Ha ha! :D You know of course where the sarcasm comes from about the SABC I presume ....
 
f2wohf said:
All those who are not in the rain and in Pretoria East for a CPT topic and these are just about everyone on this forum, are NOT entitled to comment on this thread, as you don't know what happened, nor do you know what generally happens with regard to mistakes that the rain makers make which leads to errors on the precipitations.

Give the rain a break .........
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Geoff has family in CT, and he and I are collobrating on this event.

Please refrain from commenting on things that you know nothing about (like the other thread...)
 
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