Approaching the end of the year, BMKG warns against potential extreme weather

Jakarta, domclub Indonesia
—
Towards the end of the year, Indonesia’s atmospheric and marine conditions enter its most active phase.Not only because of the peak of the rainy season, but also because of the meeting of various wind and wave phenomena that create it
weather
much more unstable.
Meteorology, Climatology and Geophysics Agency (
BMKG
) describes the atmospheric situation during December to February as a ‘dense creeping’ band, where multiple weather systems work together, from the Asian monsoon to the influence of tropical cyclones emerging in the southern hemisphere.
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BMKG Deputy for Meteorology, Guswanto, explained that global, regional and local atmospheric dynamics are active and could trigger extreme weather in the country.
“Equatorial Rossby Waves, Kelvin Waves and Madden-Julian Oscillation (MJO) still contribute to the dominance of rain in many parts of Indonesia,” said Guswanto in his official statement, Thursday (4/12).
He explained that entering December, monsoon winds from the Asian region towards Australia began to show increasing intensity.Areas such as the South China Sea and around Natuna have recorded wind speeds of more than 18 km/hour.
However, in several deep seas in Indonesia, such as the Karimata Strait to the Banda Sea, the wind still moves slower.
The peak will occur in January, when the Asian monsoon reaches maximum strength.Strong winds are prevalent in many Indonesian waters at speeds of more than 18.5 km/hour, which automatically triggers more turbulent sea conditions and waves that have the potential to exceed 1 meter.
As February enters, the monsoon usually begins to weaken, although sea conditions are not yet completely calm, especially in areas directly facing the open ocean.
Influence of square waves & tropical cyclones
Apart from the monsoon winds, swell waves from the Indian and Pacific Oceans also increase wave height, especially in the waters of western Sumatra, southern Java-NTT, and the Papua region.In the same period, the emergence of tropical cyclones in the southern hemisphere strengthened winds and raised waves in the waters of southern Indonesia.
BMKG emphasizes that Indonesia’s atmosphere is also influenced by various other phenomena, ranging from ENSO and IOD which have annual cycles, to atmospheric waves such as MJO, Kelvin and Rossby which move over a weekly period.Then, daily dynamics such as land-sea winds, as well as cross-regional phenomena such as the Cold Surge and the Borneo Vortex.
The layered structure of the Indonesian archipelago with many gaps, mountains and valleys means that wind flows never move in a straight line.This bending wind pattern then forms very diverse variations in waves and weather between regions.
Indonesia’s topographic conditions, which consist of thousands of islands and hundreds of mountains, cause the wind flow to not move in a straight line.The wind often bends following gaps between islands, mountains, hills and valleys, resulting in various wind and wave patterns.
(wpj/dmi)