Work

Synoptic background conditions and moisture transport for producing the extreme heavy rainfall event in Valencia in 2024

Year: 2025

Type: article

Abstract: ABSTRACT From 26 October to 2 November 2024, Spain experienced a record-breaking rainfall event, with the most intense episode appearing in Valencia Province. During the event, Turis station recorded a historic 24-hour precipitation of 710.8 mm, exceeding the national annual average. This resulting flood led to widespread disruption and significant societal impacts. Synoptic analyses reveal that the event was dominated by a deep cut-off low extending through the entire troposphere and persisting for approximately 186 hours. Background conditions were characterized by upper-level divergence, mid-tropospheric warm advection, and a strong southeasterly low-level jet, which promoted vertical motion and sustained moisture transport. The steep, funnel-shaped terrain along the eastern Iberian coast further triggered and enhanced the local convection. A 10-day backward Lagrangian moisture tracing using the HYSPLIT model identified the Mediterranean Sea as the primary moisture source (78.1%), followed by northwestern Africa (8.5%) and central-eastern Europe/the Black Sea (6.2%). Low-level moisture transport was mainly driven by the cut-off low and a persistent Mediterranean high, while mid- to upper-level trajectories were associated with a preceding low-pressure system over the Mediterranean and the subtropical Atlantic high. These systems acted in sequence to relay moisture toward the Valencia region, and under the influence of the strongly rotating and convergent cut-off low—along with terrain-induced lifting—this moisture was rapidly uplifted, ultimately triggering the extreme rainfall event.

Source: Atmospheric and Oceanic Science Letters

DOI: 10.1016/j.aosl.2025.100666

Authors: Tingting Huang, Shenming Fu, Xiao Li, You Dong, Yuanchun Zhang, Jianhua Sun