Met explains erratic weather

The cold season has ended, and what is currently being experienced is cloudiness, punctuated with daily fluctuations, the weatherman has said.

Nairobi and its environs experienced erratic weather from June, culminating in biting cold in the months of July and August.

However, towards the end of last month and into September, the region has been hit with a sporadic weather with mornings being chilly, then suddenly giving way to hot conditions.

According to the Kenya Meteorological Services, the recent temperature has been influenced by high relative humidity, which is above 70 percent, wind speed and cloudiness or less sunshine.

This as the weather transitions from the cold season of June, July and August into the dry month of September before giving way to the short rains of October, November and December.

Principal Meteorologist in charge of Forecasting David Koros explained that what is being experienced is not erratic weather but it is the atmosphere, the earth and the ocean trying to reorganise themselves.

Being a transition period, a back and forth between warm and cool mornings is being experienced as the dominant systems establish themselves.

“It’s not erratic weather. It’s simply the transition from the cold season into the dry month of September then the short rains season. Transition has its characteristics, where sometimes it is warm, cold or we get a lot of rainfall here and there,” said Mr Koros.

He pointed out that the cold and intermittent temperature has mostly been experienced over the eastern part of the country in the highlands east of the Rift Valley, including Nairobi, where temperatures have been low.

“It has also been in other parts of the countries but for the western parts, it has been raining, so you find that it has not been as cold as other parts, especially the eastern parts of the country,” he said.

According to the weatherman, the month of July marked the peak of the cold season, especially over areas east of the Rift Valley highlands, including Nairobi County.

An analysis of the temperature indicated that most parts of the country recorded mean temperatures that were above the long term mean for the month of July as had been predicted in the forecast.

The areas recorded day time (maximum) temperatures that were below 18 degrees Celsius against a lowest monthly average day time temperature of 19.2 degrees Celsius.

Nyahururu, Narok, Laikipia, Machakos and Ngong occasionally recorded night time (minimum) temperatures below 10 degrees Celsius, with the temperature in Nyahururu dropping to lows of 6.5 degrees Celsius against the lowest monthly average night time temperature of 9.5 degrees Celsius.

This despite most parts of the country experiencing depressed rainfall during the month, while several parts of the country remained generally dry.

For last month, the highlands east of the Rift Valley, including Nairobi County, experienced cold conditions, with the weatherman warning that the temperatures could dip to lows of 5 degrees Celsius.

Mr Koros, however, said the cold season is over, and now cloudiness is punctuated with daily fluctuations as the temperatures are back to a maximum of more than 24 degrees Celsius and a minimum of over 14 degrees Celsius.

This is because the subtropical high pressure cells in the northern hemisphere, Azores and Siberian, have started intensifying, while the previous predominant highs in the south, which have been pumping in cold and dry air mass have started relaxing.

This has resulted in development of significant clouds over the western sector of the country spilling over to highlands east of the Rift Valley.

He, nonetheless, said warmer weather is likely to be experienced from mid next week although some sunshine is likely starting today (Friday).

“Right now it is not that cold. What is coming in is cool and cloudy conditions as the minimum temperatures is not as low as what we had in June through July and August. It is the cloudiness that people are feeling, which does not mean that temperatures are low,” he said.

On the extremely cold weather experienced this time around, Mr Koros pointed out that it was expected that sea temperatures to get warmer around the western part of the Indian Ocean, which is controlling temperatures over the region, but this did not happen as it has in the previous years.

“The sea surface temperature has been warmer in the eastern Pacific and not in the western Pacific, where Kenya lies, as it has been in other years,” he said.