December 9, 2025 | 06:44 am
TEMPO.CO, Jakarta - The latest analysis from the Indonesian Meteorology, Climatology, and Geophysics Agency (BMKG) indicates that potential cyclone 91S is expected to continue causing rain in the southern region of Sumatra Island. The developing cyclone, which appeared on December 7, 2025, in the southwest Indian Ocean off the coast of Lampung, has a maximum wind speed of 20 knots, or 37 kilometers per hour, and a minimum air pressure of 1,008 hPa.
Referring to the analysis released at 19:00 WIB (Western Indonesian Times) on Monday, December 8, 2025, the chance for 91S to develop into a tropical cyclone within the next 24-72 hours, from the time of the report, remains low. However, this potential cyclone continues to trigger moderate to heavy rain in Bengkulu, South Sumatra, and Lampung.
There is also a potential for moderate waves due to potential cyclone 91S in the southwest Indian Ocean off the coast of Aceh to Lampung, as well as in the southern Indian Ocean off the coast of Banten. The sea wave height in these areas could increase to 1.25-2.5 meters.
The BMKG team also reported on the development of the now inactive potential cyclone 93W. This potential cyclone was previously detected in the North Pacific Ocean region, specifically northeast of Papua Island, since November 28, 2025. The weakening of this system is due to a decrease in atmospheric parameters, such as the wind speed no longer being significant.
In the unpredictable weather conditions, with sudden extreme rainfall, BMKG's Deputy for Meteorology, Guswanto, urges the public to be more vigilant. Residents are advised to avoid outdoor activities during thunderstorms, and to stay away from large trees and fragile buildings.
Other recommendations concern environmental hygiene, especially regarding the smoothness of drainage channels to reduce the risk of puddles and floods. The increase in rainfall due to atmospheric phenomena in the ocean should also be monitored as it can affect the activities of fishermen and sea transport users.
Read: BMKG: Two Cyclone Seeds 91S and 93W Unlikely to Develop but Still Impact Indonesia's Weather
Click here to get the latest news updates from Tempo on Google News
BMKG Explains Cause of M7.3 Hokkaido Earthquake and Tsunami Warning
3 jam lalu
An earthquake with a magnitude of 7.6 in Japan on Monday night, December 8, 2025, is not potential to cause a tsunami in Indonesia, the BMKG says.
BMKG Warns of Heavy Rain and Thunderstorms Across Greater Jakarta This Afternoon
1 hari lalu
BMKG reminds the public about the potential for heavy rain, thunderstorms, and strong winds, including in South Jakarta and East Jakarta.
BMKG: Two Cyclone Seeds 91S and 93W Unlikely to Develop but Still Impact Indonesia's Weather
1 hari lalu
The wind speed is predicted to decrease, but cyclone seeds 91S and 93W still have the potential to affect the weather and sea wave movements.
Fact Check: False, BMKG Did Not Predict a Tsunami in Lampung for Early December 2025
1 hari lalu
Fact check - Two pieces of content containing claims of tidal flooding and tsunami threats in Lampung Province are circulating on TikTok and Facebook.
BMKG: Rain and Lightning to Return to Jakarta Today
2 hari lalu
In the past few days, the Greater Jakarta area has experienced significant rainfall. Here is today's weather forecast according to the BMKG.
BMKG Warns of Heavy Rain Across Indonesia as Cyclone Seed 93W Looms
3 hari lalu
BMKG warns several areas to increase vigilance against heavy to very heavy rain.
BMKG Warns Prolonged Rain Could Trigger Mount Semeru Mudflows
3 hari lalu
BMKG has warned of possible mudflows and flash floods on Mount Semeru in East Java after morning rainfall on December 5, 2025.
BMKG Warns of Heavy Rain Throughout Indonesia Next Week
3 hari lalu
BMKG encourages the public not to panic when facing extreme weather. Local authorities are also advised to prepare simple anticipatory measures.
BMKG: Rain and Thunderstorms Persist Across Greater Jakarta Today
5 hari lalu
Based on the BMKG data, rainy weather has once again covered the Jabodetabek (Greater Jakarta) area since last Saturday.
BMKG: Heavy Rain Predicted to Hit Jakarta and Its Surroundings From Noon until Evening
6 hari lalu
The BMKG has warned the public about the potential for rain accompanied by thunderstorms and strong winds from noon until evening
