Forecast of a good rainy season

MARANYANE NGWANAAMOTHO
Staff Writer | Friday September 10, 2010 00:00

Addressing the media yesterday in Gaborone, principal meteorologist, Othata Mmolotsi said the next rainy season is expected to be good.

Mmolotsi revealed that during their review of the state of the global climate systems, they found that this year, there would be a cool breeze from the east and central parts of the Pacific Ocean, which would bring rains into the country.

“These winds are called easterlies, blowing from the east.  These are advantageous for us because they bring rain into the southern region of Africa,” he said. 

This occurrence is called La Nina, and it is known to bring cooler and moist air upon the Southern region, he explained.  This cool breeze is likely to be sustained through October this year until next year March. 

However, Mmolotsi says that most models that had been used to predict chances of rain in the country differed on the strength or amount of rains that would be seen across the country. 

“Most dynamical models generally predict a model to strong La Nina, while the majority of the statistical model forecasts indicate a weaker episode.  However, possibilities of rains are expected to strengthen and last through to march 2011,” he said.  During the first phase of the rainy season, which runs from October to December this year, the northern parts of the country are expected to have rains, heavier in some areas.  “Districts like Ngamiland, Chobe, and northern parts of the Central are expected to have rains with values ranging from 120 mm to 230 mm, especially in the northern parts of Chobe, “ Mmolotsi said.

Still this year, in the Southern parts of the country rains are expected to be average and will not be as heavy as in the Northern parts of the country. 

“In Southern parts of the country districts like Southeast, Kgatleng, eastern parts of Kweneng, eastern parts of Southern, Northeast and Southern part of the Central district are expected to have rains with values ranging from 130 mm to 180 mm,” he said. 

However, Kgalagadi, Ghanzi, Western parts of the Southern and Western parts of Kweneng Districts are expected to have rains ranging from 90 mm to 130 mm, receiving the least rains in the whole country.  Mmolotsi says that during the second phase of the rainy season, which starts in January and runs through to March next year, rains are expected to be average to above average, with likelihood of floods in some areas. “Ngamiland, Chobe and northern parts of the Central Districts will have rains with values ranging from 220 mm to 350mm especially in the northern parts of Chobe. 

There are chances of floods in these areas,” Mmolotsi indicated. 

Again, Southeast, Kgatleng, eastern parts of Kweneng, eastern parts of Southern, Northeast, southern part of the Central districts are also expecting good rains.  Rain values are expected to range from 190 mm to 260 mm. 

However, Kgalagadi, Ghanzi, western parts of Southern and western parts of Kweneng districts would have better rains in 2011.  Rain values are expected to range from 170 mm to 240 mm.