Observations show a seasonal delay of rainfall for first period
Sifelani Tsiko Agric, Environment & Innovations Editor
Preliminary observations are showing poor October-November-December (OND) rainfall across much of northern Zimbabwe and better rainfall patterns in the south — western parts of the country, giving mixed signals to the start of the 2022 -2023 cropping season, a senior Meteorological Services Department (MSD) official says.
MSD head of forecasting James Ngoma told the Herald yesterday that northern parts of the country were likely to experience poor and erratic rainfall in the October to December period while rainfall in some central and southern western regions of the country is likely to be normal to above normal over the same period.
“Areas in Matabeleland north and south, Bulawayo — in the south and western part of the country started receiving rains as early as September.
“This was followed by a dry spell and some isolated showers last week,” the chief forecaster said.
“We are expecting isolated showers over the Eastern Highlands this weekend. We expect these to spread into the interior of the country on Monday and Tuesday (next week). Most areas in the south and western parts of the country have received less than 5mm of rain.”
Zimbabwe is expected to receive normal to above-normal rainfall in the 2022 – 23 cropping season, according to the Zimbabwe National Climate Outlook Forum.
“There might be a false start in northern parts. Some areas might not receive rain as the systems have not fully established. Rains are more likely in the south western part of the country where there are forecasted to be normal to above normal for the October — November — December period while in the northern part, rains are forecast to be below normal to normal as the Inter-tropical Convergence Zone (ITCZ) which normally bring rains might delay,” Ngoma said.
Zimbabwe and most southern African countries experience most of their seasonal rain from the seasonal shifts of the ITCZ coupled with rare and episodic occurrences of cyclone-induced rains.
At this time of year, the north -easterly monsoon of East Africa moves into the region forming a boundary with the easterly winds moving in from the Indian Ocean along the Inter-tropical Convergence Zone (ITCZ).
Most southern African countries experience most of their seasonal rain from this system.
The ITCZ is described as a zone that encircles the earth and is roughly parallel to the equator. It moves north and south following the sun. The ITCZ brings cyclonic rainfall to Zimbabwe and most other southern African countries during the December-January months.
The MSD chief forecaster said the nation will continuously be updated on the rainfall pattern as the season progresses.
“A showery start to the weekend is expected over the Eastern Highlands into Harare Metropolitan and Mashonaland East, with the biggest threat being the potential of lightning strikes. Thus the reminder that, when thunder roars it is best to be indoors,” the MSD said in a Thursday report.
In Zimbabwe, the rainfall season starts in October and gradually increases to a peak in January every season.
The highest rainfall is normally received in January and the rainfall starts decreasing from February through March, when the season ends.
Regional climate experts are forecasting a wetter spell for the region.
The positive climate outlook is attributed to an expected La Nina episode during the coming season.
La Nina conditions are triggered by the cooling of temperature in the Pacific Ocean and are usually associated with heavy rains and flooding in southern Africa.
The forecast is good news for the region with some parts that were hit by droughts last season.
In the 2021-2022 rainfall season, a total of 6 tropical cyclones battered several SADC countries, including Madagascar, Malawi, Mauritius, Mozambique, South Africa, Zambia and Zimbabwe.
The tropical storms and cyclones brought heavy rains and strong winds, causing significant flooding and landslides, and resulting in fatalities, displacements, destruction of infrastructure and flooding.
The season also experienced unprecedented floods in some parts of South Africa.
However, the 2021-2022 rainfall season in the region was largely marked by above-average rains in some regions and poor and erratic rainfall in others.
The late onset and early off-set of rainfall, rising input costs, excessive rainfall in some parts and drought in others had not bode well for the 2021-2022 cropping season in the region.
Rainfall received during the second last half of the season in January to April period came too late in the production season to save crops in most regions of the country.
Zimbabwe’s maize output is projected to decline 43 percent in the 2021 – 2022 agricultural season due to poor distribution of rainfall.
Maize production estimates were set at 1 557 914 metric tonnes, which is 43 percent lower than the 2 717 171 metric tonnes that was received in the previous farming season.