The Gauteng Weather and Storm Warning Thread!

Gordon_R

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Jul 5, 2009
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Looking at the satellite loop this evening in IR... I'm not too sure what I'm looking at moving in from the east
Is it an air mass (considering the cloud hugging the escarpment is still visible) or is it fog.... :unsure:

@Geoff.D @Gordon_R


For those who don't know what I'm on about, watch this line move west
Looks like fog. There is no significant weather anywhere in the country for the next 3 days.

Edit: There is a specific EUMetsat image tuned for night-time fog observations: https://eumetview.eumetsat.int/static-images/MSG/RGB/FOG/SOUTHERNAFRICA/

Very cold over almost the entire country overnight and early tomorrow morning (Fri 14th).

tmin2m_030[20190615_0000].gif
 
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Segg

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So the reason for this Mornings fog if anyone is interested, the dew point was around 3°C and the temperature on the ground sank to about 4°C - with light winds and a 1° spread fog is what you get

The past few days (and what is typically the case) the dew point has been around -5 to -10 with the minimum temperatures only getting down to 5 or 6 so a greater dewpoint spread
 

Gordon_R

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So the reason for this Mornings fog if anyone is interested, the dew point was around 3°C and the temperature on the ground sank to about 4°C - with light winds and a 1° spread fog is what you get

The past few days (and what is typically the case) the dew point has been around -5 to -10 with the minimum temperatures only getting down to 5 or 6 so a greater dewpoint spread
If you really want to get technical, you can follow the (free) SAWS aviation reports, which predict fog (obviously!), and also show the temperature and dew point:
http://aviation.weathersa.co.za/#showTAF
http://aviation.weathersa.co.za/#showMetars

The dew point is currently 5C at ORT at 11am, which is quite high for a normally dry winter climate.

The fog and low cloud is predicted to clear during the day:
BECMG 1407/1409 3000 BR BKN005
BECMG 1409/1411 32010KT CAVOK
The fog is not overly impressive on a satellite image, but is clearly visible over parts of Gauteng and Mpumalanga, along with low clouds over Botswana and Zimbabwe:

MET9_721-southernAfrica_20190614_0600[crop_25X2].jpg
 

The_Librarian

Another MyBB
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Summer is not here yet, do not break out the swimming gear.

It's nice weather now. Just the right mixture of hot and cold. Wish it could stay like this forever.
 

Cius

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Jan 20, 2009
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Would love some rain, damped down the dust a bit. My sinuses are permanently under assault this time of year.
 

Gordon_R

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There is a very weak trough (500hPa level) moving over the central interior of SA today (Mon 5th). It may bring some upper instability, which could be of concern for light aircraft, but the chances of rain actually hitting the surface are rather remote.

Edit: For example this is the aviation Terminal Aerodrome Forecast for Mahikeng airport:
TAF AMD FAMM 050800Z 0507/0518 VRB03KT CAVOK
TX29/0513Z TN15/0518Z
PROB30 TEMPO 0507/0514 FEW065TCU
PROB30 TEMPO 0510/0512 TS FEW055CB
BECMG 0510/0512 32010KT
Decoded:
Temporary time: [Day 05 07:00] Until time: [Day 05 14:00]
Clouds: Few Clouds (1 to 2 oktas) at 1950 metres (6500ft) is towering Cumulus Cloud

Temporary time: [Day 05 10:00] Until time: [Day 05 12:00]
Weather: Thunderstorm
Clouds: Few Clouds (1 to 2 oktas) at 1650 metres (5500ft) is Cumulonimbus Cloud

gfs_africa_006_500_vort_ht[20190805_0600_06Z_crop].gif

Edit: The trough is nicely visible on this morning's satellite image:

MET9_721-southernAfrica_20190805_0600[crop_25X2].jpg

Source: https://eumetview.eumetsat.int/static-images/MSG/RGB/NATURALCOLOR/SOUTHERNAFRICA/
 
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