KUALA LUMPUR: It’s not just heavy rains and strong winds that will potentially impact Malaysia ahead of the year-end rainy season.
Lightning is another cause for concern, with experts saying Malaysians can expect thunderstorms to be more frequent across the country in the coming months.
According to the Malaysian Meteorological Department (MetMalaysia), Malaysia is at the final phase of the southwest monsoon and is expected to transition towards the intermonsoon period later this month.
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It said the country typically experiences light winds from variable directions during the intermonsoon, which are conducive to the development of thunderstorm clouds.
Malaysia experiences two inter-monsoon periods – between late March and May and between September and October.
“These conditions may result in heavy rainfall accompanied by strong winds over short periods, particularly during the afternoon and early evening across most areas.
“Thunderstorms may potentially lead to flash floods, fallen trees and damage to unstable structures,” MetMalaysia said in its long-term weather outlook from September 2026 to February 2027.
Climatologist Prof Emeritus Fredolin Tangang from Universiti Kebangsaan Malaysia said localised thunderstorms can be part of weather patterns during the intermonsoon period.
He said localised storms usually occur in a relatively short period of between one and three hours.
“Weather forecasts issued at least six hours in advance can give a reasonably reliable indication of whether thunderstorms are likely to develop in a particular area,” he added.
He said among the precautions that can be taken are to always pay attention to weather forecasts issued by MetMalaysia.
“Avoid open spaces during thunderstorms as the risk of lightning is higher. River recreation should also be avoided in unfavourable weather conditions as the risk of sudden water surges can rise,” he added.
Lightning expert and consultant engineer Hartono Zainal Abidin said thunderstorms remain elevated throughout the inter-monsoon and northeast monsoon period, and generally only dip during the dry period between June and August.
“Due to the forecasted arrival of the strong El Nino phenomenon, thunderstorms and lightning may decrease during the coming northeast monsoon.
“This is because the phenomenon is known to decrease the amount of moisture in the atmosphere,” he added.
Unlike temperate countries where broad storm fronts develop over several days, he said tropical thunderstorms in Malaysia can develop within a few hours.
Hartono also proposed that instead of providing weather forecast reports during scheduled news broadcasts, advance warnings on the development and presence of thunderstorms can be done on an hourly basis over news channels.
Hartono added that thunderstorms and lightning episodes usually last about an hour or two for tropical thunderstorms.
“People can predict a thunderstorm when they see dark clouds developing nearby for about 30 minutes before the first clap of thunder is heard.
“Take shelter upon seeing the thundercloud as lightning can occur before the rain starts. All open air activities are dangerous during this period,” he said.
