the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 23 Mar 2026
Brief communication: Extreme rainfall–driven flooding associated with the equatorial development of Tropical Cyclone Senyar in Aceh, Indonesia
Abstract. In late November 2025, extreme rainfall associated with the rare equatorial regeneration of Tropical Cyclone (TCs) Senyar triggered severe flooding across northern Sumatra, with Aceh Province experiencing the most severe impacts. Using satellite-based rainfall estimates from GPM IMERG, ERA5 reanalysis, and surface observations from BMKG, this brief communication provides a rapid hydrometeorological assessment of the event. Daily rainfall locally exceeded 400 mm on 25–26 November, concentrated over northern and eastern Aceh. Synoptic analysis indicates that, despite limited surface pressure deepening near the equator, persistent low-level moisture convergence and strong integrated vapor transport from the Malacca Strait, enhanced by orographic lifting along the Barisan Mountains, produced extreme rainfall and widespread flooding.
- Preprint
(1952 KB) - Metadata XML
- BibTeX
- EndNote
Status: open (until 10 May 2026)
-
CC1: 'Cyclone Senyar in Tropical athmosphere..', Muslim Amiren, 07 Apr 2026
reply
-
AC1: 'Reply on CC1', Saumi Syahreza, 07 Apr 2026
reply
We thank the commenter for this insightful question. We agree that the observed impacts do not fully resemble those of a mature tropical cyclone, as no clear eye or symmetric circulation was present. As noted in the manuscript, the system exhibited asymmetric circulation and lacked a well-defined inner core. It is therefore better interpreted as a developing or marginal cyclonic disturbance in a near-equatorial environment. Nevertheless, persistent convection and strong moisture convergence produced extreme rainfall and flooding. We will revise the manuscript to better clarify this distinction. Thank you again for this valuable comment.
Citation: https://doi.org/10.5194/egusphere-2026-694-AC1 -
AC2: 'Additional clarification on system structure', Saumi Syahreza, 08 Apr 2026
reply
We would like to further clarify that the system was not entirely asymmetric. As described in the manuscript, it exhibited a partially organized structure with noticeable asymmetry, rather than a fully developed symmetric cyclone. We will revise the manuscript to better clarify this distinction.
Citation: https://doi.org/10.5194/egusphere-2026-694-AC2
-
AC2: 'Additional clarification on system structure', Saumi Syahreza, 08 Apr 2026
reply
-
AC1: 'Reply on CC1', Saumi Syahreza, 07 Apr 2026
reply
Viewed
| HTML | XML | Total | BibTeX | EndNote | |
|---|---|---|---|---|---|
| 83 | 37 | 10 | 130 | 11 | 11 |
- HTML: 83
- PDF: 37
- XML: 10
- Total: 130
- BibTeX: 11
- EndNote: 11
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1
It is very interesting to know more about Cyclone Senyar. Why does it occur in Tropical nature background. I saw, there is no actually cyclone, but only a huge flooding. Could we still say a cyclone senyar, or other name to call? Would you please you explane how is it different in characteristic of a Tropical Senyar cyclone?
Thanks so much,
Muslim Amiren