The Meteorological Services Department of Zimbabwe (MSD) has predicted determined likelihoods of above-normal, normal and below-normal rainfall for each area i.e. October-November-December (OND), and January-February-March (JFM); taking into account oceanic (sea surface temperatures) and atmospheric factors that influence our climate over SADC region (which includes Zimbabwe), in particular the El Niño-Southern Oscillation (ENSO).
ENSO is the interaction of anomalous sea surface temperatures and atmospheric pressure over the eastern tropical Pacific Ocean. This phenomenon affects climatic patterns around the globe. The term ENSO refers both to El-Niño and La-Niña phenomena and the Southern Oscillation. In the case of Zimbabwe, a rainfall season that follows an El Niño has a high probability of being dry while a season that follows a La Nina event is highly likely to be wet.
Speakeing to AgriSeason, the Midlands Meteorological Services Department of Zimbabwe (MSD), Chief Meterological Officer, Mr. Tafirenyika Zinyowera, said that the firest half of the rainy season, that is from October to November, 2019, the season is expected to be normal with a bias to below normal. From December to January the season is widely expected to be below normal.
Mr. Zinyowera said that the Gweru is expected to recieve an average 664mm this year and farmers optimally use the water and grow short season high yielding varieties as the distribution pattern is not yet known, adding that dryland farmers may be affected unless the rains are distributed evenly throughout the season.
Mberengwa generally has the same rainfall patterns as Gweru while Gokwe South and North are expected to recieve above normal rains for the first part of the season.
There are other indicators that are also used such as the Indian Ocean Dipole (IOD), sea surface temperatures (SST) among others.
The 2018/19 rainfall season is expected to be erratic in space and time. The forecast is for total seasonal rainfall amount.
October rains are generally erratic for rain-fed agriculture, more meaningful rains normally begin at the end of November into December.
It would be prudent to put in place measures for early cloud seeding programme in light of the expected erratic rainfall season throughout the country.
In view of the moisture availability and suitable temperature thresholds, those with irrigation facilities should not wait for the main rains to fall. They can plant any time now, taking into account the high temperature needed for germination;
Violent storms, prolonged dry spells, flash floods and tropical cyclones cannot be ruled out as the season progresses.
There is need to continue with water harvesting programmes.
The policies of small dam construction and borehole drilling/ deepening, conservation and protection of wetlands should continue, more so in the Southern Provinces of the country;
Application of fertilizers should be guided by the 10-day weather forecasts as well as advice from Agricultural authorities; (Conservation, e.g., contouring and ridging/ smart agriculture); The 10-day weather forecasts will be issued from October until end of season.
Development partners, research institutions and all stakeholders should continually monitor the rainfall season and provide the necessary assistance when need arises.
By Francis Bingandadi Managing Editor AgriSeason