Rain and storm for Cpt

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We should dig South Africa free along our neighbours borders and insert some Ram jacks and push the country down further south towards the rain.. if the rain won't come to us, we will go to the rain..
 
WAslayer said:
We should dig South Africa free along our neighbours borders and insert some Ram jacks and push the country down further south towards the rain.. if the rain won't come to us, we will go to the rain..
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Or just come to Joburg and enjoy the majesty of our summer thunderstorms :whistling: ;)
 
Gordon_R said:
It has been extremely dry for most of this month, and the situation is somewhat concerning. A few cold-fronts have brought some rain over the mountains, with a little inflow into the dams, but not much elsewhere.
Rain and very cold conditions are predicted for Fri 21st, but still well below the seasonal average.
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Yep, if I look at this time last year:
21MAY-17JUN - big six increased by approx. 17% - this year has been flat'ish

I tracked the ratio of big six TY to LY:
It reached a high of 2.37 on 22APR, currently sitting on 1.28
If we receive limited rain from now until 08JUL, we will have less water in our dams than last year (.91)

Dammit, quite sobering to say the least, fingers X'ed.

Even Jonkershoek is well below LY's number and still a bit of rain needed to get to 3rd best year out of the last 6.
 
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Latest forecasts show a very intense frontal low passing just south of CT on Fri 21st. This will bring moderate amounts of rain, very strong winds, and extremely cold temperatures:

mslp_6h_totp_066[20190621_1800_crop].gif
 
Fairly dramatic SAWS warning:
High seas with wave heights of 6 m to 7.5 m is expected between Cape Columbine and Cape Agulhas from Friday evening, spreading to Port Elizabeth on Saturday morning, subsiding from the west by the afternoon.

Gale force north-westerly winds (60km/h to 75km/h, gusting at 80km/h to 100km/h) are expected in places over the Karoo Hoogland (Northern Cape), Central Karoo, Breede Valley, Cape Peninsula and coastal regions between Table Bay and Plettenberg Bay on Friday.
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Periods of heavy downpours may occur, which could lead to localised flooding. Informal settlements on the Cape Flats and the Overberg District are likely to be amongst the areas most vulnerable to flooding.

Snowfalls are also likely over the southern mountains of the Western Cape on Friday night to Saturday morning.
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Source: http://www.weathersa.co.za/Documents/Corporate/Media release 19 June 2019.pdf
 
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Snowfalls are also likely over the southern mountains of the Western Cape on Friday night to Saturday morning.

Ouch. Much higher elec bills on their way this month and next!
Been rather nippy ( even dare i say, frigid @ 8-9C a few nights this week already)
 
Ja surprising change in the forecast for the cold fronts on the way, 3 of them, pushing further north than originally predicted a week ago. Sharp movement of the AAO index also towards zero.
The cold is going to penetrate quite far north but the rain is going to along the Coastal areas up to the mountains.
 
MirageF1 said:
Snowfalls are also likely over the southern mountains of the Western Cape on Friday night to Saturday morning.

Ouch. Much higher elec bills on their way this month and next!
Been rather nippy ( even dare i say, frigid @ 8-9C a few nights this week already)
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What 8 - 9 Cold? we have had a few nights down to 4 degrees this week. Long time since that has happened.
 
Geoff.D said:
What 8 - 9 Cold? we have had a few nights down to 4 degrees this week. Long time since that has happened.
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For Southern suburbs yes... for Johies or interior no

I lived in Siberia for as few months, so yes, this is a summer holiday relatively speaking :sneaky:
 
Current Satellite Image :D

And the TAF (Times in Zulu) Looks like some hectic winds as well :oops:

Fromtime: [Day 21 09:00]
Wind direction:340 degrees
Wind speed:7.7 m/s (15kt)
Visibility:10km or more
Few Clouds (1 to 2 oktas) at 450 meters (1500ft)
Broken Clouds (5 to 7 oktas) at 900 meters (3000ft)



Temporarytime: [Day 21 10:00] Until time: [Day 21 18:00]
Wind direction:300 degrees
Wind speed:13.4 m/s (26kt) Gusting to 20.6 m/s (40kt)



Temporarytime: [Day 21 12:00] Until time: [Day 21 18:00]
Horizontal visibility:4000 metres
Weather:Light Rain
Broken Clouds (5 to 7 oktas) at 300 meters (1000ft)



Capture.JPG
 
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The upcoming system hardly appears on the current synoptic chart and satellite image. During the next 24 hours there will be a process of rapid intensification (called a weather bomb).

This is driven by a pool of cold upper air, which will unleash a mix of instability and rotation. (Bad analogy: Like a hippopotamus jumping off a diving board into a kiddies paddle pool).

Thundershowers are likely to be triggered by the instability, which is relatively rare for cold fronts in the Cape, and this is one of the reasons for warnings about localised flooding.

Mostly accurate but highly dramatised prediction of tomorrow's events: https://www.wavescape.co.za/surf-ne...PvazMOUc0sIZ6E2wus4fDcrr7LwhhSmP0PvWe6GGuB5E4
 
The models that predict the weather have to look at a number of different variables, but also look at different levels of the atmosphere. This particular storm provides an excellent example of how events will unfold, and how the models interpret the data.

The current situation (satellite image on Thurs 20th) can be summarised as a relatively modest surface development (isobars), with an intense cold-core upper-trough (dotted blue and red-lines) ridging in behind:

gfs_africa_006_1000_500_thick[20190620_1800_06Z_crop].gif

By tomorrow afternoon (Fri 21st) the surface isobars (solid black lines) will have developed into a compact and very intense frontal low. Everything follows on from that.

gfs_africa_036_1000_500_thick[20190621_1800_36Z_crop].gif
 
Still clear skies and warm this morning. Let's see what the day brings.
 
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