Meteorological trouble brewing in RI skies
By Edith Hartanto
JAKARTA (JP): The National Meteorology and Geophysics Agency predicted yesterday that the final months of the dry season will be characterized by thunder, lightning, storms and hail.
The head of the agency's meteorology service, Widodo Sulistya, told The Jakarta Post that the formation of convective clouds were to blame for the uncertain weather patterns.
"Convective clouds usually hang high in the sky, sometimes 10 to 15 kilometers above the ground.
"Because the temperature is low up there, the particles drop to the ground in the form of ice cubes," he said. "That is why some areas in Java are experiencing hail."
Earlier this month, the West Java city of Bandung was reportedly showered with hail.
"If the ice fell in little cubes that would not be a problem. But if it is bigger, you can imagine how painful it would be to be hit by one," Widodo said.
While the clouds cover Jakarta's sky, the wind will increase to approximately 45 kilometers (25 knots) per hour compared to the current speed of about 20km to 25km per hour.
Judging from the convective clouds and increase in wind speed, the coming rain season, expected to start next month, will probably cause trees to fall and damage houses which do not have solid foundations.
"In certain areas of Jakarta it will rain cats and dogs followed by heavy storms," he said.
He said that the agency was closely monitoring the change of the season with climate radar, satellites and sonde radio.
"Radar and satellites are used to watch the dynamic atmosphere changes while the sonde radio measures the stability of the air," he said, adding that the more unstable the air, the easier it was for convective clouds to form.
It is normal for Indonesia, as an equatorial country, to have convective clouds form in its skies.
"We are a tropical country with only two seasons," he said. "The hot air forms the clouds and the wind pushes the clouds high in the sky."
Because there are trade winds above Indonesia, which move from north to south, the clouds will be blown to the southern part of Indonesia.
"So, the clouds will certainly affect Java," he said.
In Jakarta, the unpredictable weather pattern will last about one month before the real rain begins to fall in mid-November. The hottest weather in the city has already passed, with peak temperatures on Sept. 23, Widodo said.
The agency has also forecasted the weather patterns for the rainy season in Jakarta.
The head of the agency, Sri Diharto, said last week that the rain would start in the city during the second week of this month, spreading sporadically from the South Jakarta area.
Sporadic rain has already fallen over a number of cities, including some parts of Jakarta yesterday.
"The heavy rain will only begin in December and it will usually continue until March," Diharto said.
Widodo said that the heaviest rain will fall in January and, as usual, it will probably cause extensive flooding in the city.
The agency warned the city administration and other related bodies to prepare for the coming rainy season.
According to Widodo, there are four main reasons for flooding: heavy rain, inadequate pipelines and underground drainage systems, lack of green areas to absorb water and the limited availability of water reservoirs.
He said that city officials and the community must start cleaning gutters, rivers, dams and provide more water catchment areas, primarily lakes.
"I simply urge the public to stop littering in certain places, including rivers or gutters, and the municipality to take care of the development projects that were completed in the previous dry season.
"I'm sure that many development projects also have material wastes, which will block the water flow in the rainy season," Widodo said. "Developers may not be aware of the danger but when it rains it's a totally different situation."
Flooding will not occur if people are aware and take good care of their environment, he said.
"The lack of green areas to absorb the rain will probably be the main reason why Jakarta suffers from flooding."