The emergence of Tropical Cyclone SENYAR in the Strait of Malacca on 26 November 2025 has drawn significant attention from communities in Aceh and northern Sumatra. This phenomenon has raised concerns not only because of the severe weather it brings, but also because of the unusual location where it developed—very close to the equator, a region long believed to be nearly immune to tropical cyclones. According to official data from Indonesia's Meteorological, Climatological, and Geophysical Agency (BMKG), SENYAR intensified from Tropical Cyclone Seed 95B and is now moving toward Indonesia, carrying the potential for extreme rainfall, strong winds, and high waves across parts of Sumatra.
Based on BMKG’s analysis at 07:00 Western Indonesia Time, the initial position of SENYAR was detected at 5.0°N and 98.0°E, or roughly 90 kilometers southeast of Lhokseumawe in Aceh. At that time, maximum wind speeds reached 43 knots (about 80 kilometers per hour), with a central pressure of 998 hPa. SENYAR was classified as a Category 1 Tropical Cyclone and was moving slowly westward at around 10 kilometers per hour toward the northern coast of Aceh. BMKG forecasts that within 24 hours, or by 07:00 on 27 November, SENYAR will shift inland toward Aceh Tengah Regency, about 95 kilometers southwest of Lhokseumawe. Although its intensity is expected to weaken slightly—dropping to 38 knots (70 kilometers per hour) with pressure rising to 1004 hPa—the cyclone will remain within Category 1.
Despite this weakening trend, SENYAR’s close proximity to Indonesia makes the system dangerous. Heavy rainfall and strong winds often persist even as the cyclone’s core circulation decays, as the surrounding convective cloud structures remain highly active. This is why residents of Aceh, North Sumatra, West Sumatra, and even Riau are urged to increase their vigilance against potential hydrometeorological disasters associated with SENYAR’s passage.
The formation of a tropical cyclone this close to Aceh is undeniably rare, yet it does not violate meteorological theory. Tropical cyclones require a minimum distance of roughly five degrees latitude from the equator in order to develop, because the Coriolis force—which enables the atmospheric rotation that gives cyclones their spin—weakens drastically near the equator. SENYAR formed at exactly 5.0°N, placing it at the absolute lower threshold where rotational forces still exist. Atmospheric and oceanic conditions in late November created a highly favorable environment for Tropical Cyclone Seed 95B to strengthen. The Strait of Malacca is known for its warm sea surface temperatures, providing ample energy for the growth of towering convective clouds. At the same time, high humidity levels and a favorable vertical wind structure allowed the low-pressure system to maintain and intensify its circulation.
These combined factors explain why SENYAR was able to form so close to the equator. The phenomenon also serves as a reminder of increasingly dynamic weather patterns in tropical regions. Rising global sea surface temperatures linked to climate change may be expanding the potential formation zones of tropical cyclones toward more equatorial latitudes. In this context, the intensity and distribution of cyclone formation could shift in the coming years. For a country like Indonesia—positioned almost entirely within tropical latitudes—this underscores the need to reassess long-standing assumptions about cyclone risks.
BMKG reports that SENYAR will cause significant weather impacts across Indonesia. Aceh and North Sumatra are expected to experience very heavy to extreme rainfall over the next 24 hours, bringing risks of flooding, flash floods, and landslides in vulnerable areas. West Sumatra and Riau are also forecast to experience moderate to heavy rainfall as an indirect effect of SENYAR’s circulation. Strong winds are expected in several coastal regions, increasing the likelihood of fallen trees and minor infrastructure damage. Meanwhile, sea conditions are expected to worsen considerably. The northern Strait of Malacca, waters off Aceh, and the Indian Ocean west of Aceh through Nias may see waves reaching 2.5 to 4 meters, posing serious risks to shipping and fishing activities.
In light of these conditions, BMKG urges communities in affected regions to remain alert and follow official updates from meteorological authorities and local governments. Marine activities—especially in the Strait of Malacca and Aceh waters—are strongly discouraged until conditions improve. Residents in flood- and landslide-prone areas are advised to prepare early, safeguard essential belongings, and ensure access to safe evacuation routes if needed. The public is also reminded not to circulate or rely on unverified information, particularly content shared via social media.
Tropical Cyclone SENYAR serves as a clear reminder that the era of extreme weather has reached the equatorial zone. Although Indonesia has long been considered safe from tropical cyclones, the increasingly complex dynamics of the atmosphere demand greater vigilance. Public awareness of extreme weather risks and preparedness for disasters are essential to reducing the impacts of events like SENYAR, which may become more frequent in the future. With accurate information and strong community readiness, Indonesia can face such hazards with greater resilience.