BMKG: Beware Of Extreme Weather In North Sumatra Until December 15

The Meteorology, Climatology and Geophysics Agency (BMKG) reminded the public to be aware of the potential for extreme weather in a number of areas of North Sumatra (North Sumatra) that could occur from 8 to 15 December 2025.

Head of the Center for Meteorology, Climatology and Geophysics (BBMKG) Region I Hendro Nugroho said BMKG identified the presence of Tropical Cyclone 918 Seeds in the Southwest Indian Ocean Lampung which resulted in wind bends and confluence (air masses meeting) in North Sumatra.

Tropical Cyclone 91S is also supported by active atmospheric waves and Madden-Julian Oscillation (MJO) around its circulation center. The negative Indian Ocean Dipole (IOD) condition will continue until December 2025.

In addition, he said, the sea surface temperature was observed to be warm, ranging from 29-30 degrees Celsius and high humidity in all atmospheric layers.

With these factors, he continued, the North Sumatra region is predicted to receive additional water vapor, resulting in an increase in the formation of rain clouds, especially in the western coast.

Areas that have the potential for heavy and very heavy rain include Dairi, Pakpak Bharat, Humbang Hasundutan, Nias, South Nias, North Nias, West Nias, Gunungsitoli City, Central Tapanuli, and Sibolga City.

The same condition can also occur in South Tapanuli, Padang Sidempuan City. North Tapanuli, Mandailing Natal, Padang Lawas, North Padang Lawas, Langkat, Medan City, Binjai City, Deli Serdang, Karo, Simalungun, Samosir, Serdang Bedagai, Pematang Siantar City, and South Labuhanbatu.

BBMKG Region I urges the public to be more vigilant because in the next week (8-15 December 2025) several areas in North Sumatra are expected to experience an increase in the intensity of rain.

The community is expected to be able to take anticipatory steps so that daily activities can continue safely and smoothly.

Given that the weather is dynamic, he said, the public is expected to continue to monitor the latest information from the BMKG.

Regional heads are also advised to coordinate with BPBD, TNI, local Police, to continue to follow the information submitted by BBMKG Region I Medan through social media @infobmkgsut.

"We remind the public not to easily trust weather information from unofficial sources and to contact the BBMKG information service area I through the call center at 0821-6804-3653 or bbmkgl email @bmkg.go.id," said HendroNugroho.