New Zealand to Experience Severe Wind and Rain

Affected by an upper-level low vortex and a low-level jet stream (Figure 1), a significant storm with heavy rain and strong winds is expected in New Zealand from April 16 to 19. The central and southern parts of the North Island and the western part of the South Island will experience heavy to torrential rain, with localized extremely heavy downpours. Accumulated precipitation in most of these areas is forecasted to be between 60 and 110 millimeters, with some localized areas potentially exceeding 140 millimeters (Figure 2). Additionally, these regions will be accompanied by strong winds of 4 to 6 on the Beaufort scale, with gusts reaching 7 to 9 (Figure 3). Attention should be given to the potential secondary disasters caused by the heavy rainfall, such as flash floods and urban waterlogging.

Figure 1: Forecast of 500 hPa Geopotential Height (contours, units: dagpm) and 850 hPa Wind Field (wind barbs, units: m/s) at 20:00 BST on April 17, 2026

Figure 2: Accumulated Precipitation from 20:00 on April 16, 2026, to 20:00 on April 19, 2026 (Beijing Time), in millimeters (mm)

Figure 3: Forecast of Maximum Gust Wind Speed from 20:00 on April 17 to 20:00 on April 18 (Beijing Time) (Unit: m/s)

https://www.wmc-bj.net

Author: Bao Huimeng                                      Reviewer: Guan Yue 

English reviewer:Wang Yi                                                                       Issue approver:Dai Kan