Guest Contributor | Oct 5, 2021 | 0
Weather overview and short-term outlook to Wednesday 07 July 2021
Visual: Synoptic map of surface pressure on Friday 02 July at 14:00.
Source: South African Weather Service, www.weathersa.co.za/images/data/specialised/ma_sy.gif .
While many people expected a colder winter following the very wet rain season, to date it has not materialised. If current conditions, as indicated on this week’s visual, persist, the first two weeks of July will also not see severe cold.
This view is supported by two leading forecasts, both showing that while temperatures in the Hardap and Karas regions may approach zero by about 06:00 in the mornings, the general consensus is that is will not actually go below freezing point and that the risk of frost is absent or very small.
So far this season, the winter has proven to be rather mild. During June, three cold fronts have made landfall in the Western and southern Cape but due to their mobility, the wet and cold impact was limited to three or four days.
Their fast migration from west to east was also witnessed in Namibia where colder conditions persisted for only two days on each of the three passings. It must be remembered that Namibia’s winter weather is only an extension of the Cape’s weather, at least as far north as Grootfontein.
This week provided another point in case. It rained incessantly in the Western Cape from Sunday afternoon, and during Tuesday typical damp winter conditions were present at Oranjemund and over the southern Namib but by Wednesday evening, the skies were mostly clear again. The remnant of that front can be seen on the synoptic map far south-east of Madagascar.
It has been a regular feature that the cold fronts are deflected by strong low-pressure systems south of Cape Agulhas, amplified by high pressure control in the middle layers of the atmosphere, particularly over southern Angola, central Namibia and central Botswana
As can be seen on the visual the next cold front is about a day away from Cape Town but the chances are good that is will be deflected and not make landfall, or if it does, that its impact will be short-lived.
The expectation for Namibia is that the end of the weekend will turn colder in the Karas region and perhaps in the Hardap region, but not over central and northern Namibia where the days will be mild, even warm in the north-west and Zambezi.
On the Radar
The weekend starts with a continuation of the conditions of the past three days – cool nights but temperatures not approaching zero, with pleasant, quiet days that may go as high as 21°C in the south, 24°C over the central areas and 28°C in the northern areas.
The next approaching frontal system is driven by the leading rim of the South Atlantic high pressure cell and should reach Oranjemund during Sunday.
This will lead to somewhat windy conditions over the southern Namib but nothing out of the ordinary.
The local intrusion will be very limited, visible only on Monday and perhaps Tuesday morning in the Karas region.
It must be noted that there is fairly strong high pressure control at the 500mB level (about 5,8 kilometres aloft) and this ‘thicker atmosphere’ inhibits the effect of the cold front on the surface.
All in all, the whole of Namibia should see another mild week very similar to this week. The typical frosty July conditions are not on the radar yet.