SA Weather Service’s storm radars on and off due to load shedding

Load shedding is apparently knocking the South African Weather Service’s (Saws) land-based radar platforms out of commission, with only three out of 14 allegedly working by yesterday afternoon.

The issue was brought to light yesterday on Twitter by independent commercial weather service Afriwx (sawx.co.za).

It is not to be confused with Saws, the country’s official weather information provider.

Radars monitor severe weather

“Some very important radars for monitoring severe weather during this cut-off low are now also offline,” Afriwx claimed.

“What an embarrassment that this is a [World Meteorological Organisation] certified institution and the ‘Official voice of weather in South Africa’, a voice that seldom speaks, certainly not when people’s houses are being destroyed because they simply cannot even see on their own radars what is happening,” said Afriwx.

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It claimed some radars have been offline for months and some for years, and “can’t blame everything on load shedding”.

According to Saws spokesperson Oupa Segalwe, the radars switch on and off intermittently depending on load shedding schedules, availability of diesel and general breakdowns.

“Some of the breakdowns result from the power outages and surges,” Segalwe said.

He noted the radars were used for storm tracking and warnings and alerts in conjunction with other “numerical weather prediction (NWP)” forecasts.

According to the US National Oceanic and Atmospheric Administration, NWP is a method of weather forecasting that employs a set of equations that describe the flow of fluids.

“These equations are translated into computer codes and use governing equations, numerical methods, parameterisations of other physical processes and combined with initial and boundary conditions before being run over a domain [geographic area],” the organisation said.

“Almost every step in NWP includes omissions, estimations, approximations and compromises.”

Other observational tools

To address the issues, Segalwe said Saws had “procured additional infrastructure including uninterrupted power supplies, automatic voltage regulators, air-conditioning systems and diesel generators”.

He added: “This notwithstanding, Saws is able to and does render services daily, relying on other observational tools such as satellites, over 250 automatic weather stations (AWS) and automatic rainfall stations (ARS) across the country and upper-air soundings as well as lightning detection sensors.

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“All of which ensure that forecasts are accurate and not compromised and that early warnings are issued timeously, as has been the case over the last couple of days.”

The Citizen attempted to speak to Afriwx, but the organisation did not respond to messages.

– amandaw@citizen.co.za