Southeastern Australia and Northern New Zealand Experience Severe Wind and Rainfall Conditions

It is forecasted that from June 30 to July 4, influenced by an upper-level trough and a cutoff low vortex (Figure 1), eastern Australia and northern New Zealand will experience moderate to heavy rainfall, with localized heavy downpours or intense rain. In high-altitude areas, light to moderate snow or sleet is expected. Accumulated precipitation in parts of southeastern Australia and the North Island of New Zealand could reach 40-90 mm. Coastal areas of southeastern Australia, eastern Auckland Region, northeastern Waikato Region, and northern Bay of Plenty Region may see accumulations exceeding 120 mm, with localized totals surpassing 200 mm (Figure 2). Additionally, most of these regions will be accompanied by winds of 5-6 on the Beaufort scale, with gusts of 7-8, and coastal areas may experience gusts reaching 9-11 (Figure 3). From July 5 to 6, as the system moves eastward and weakens, some parts of New Zealand's North Island will still experience showers, with winds decreasing to 4-5 on the Beaufort scale. This event, characterized by heavy rainfall and strong winds, necessitates close monitoring for adverse impacts on power facilities, transportation, and other industries.

Figure 1  500 hPa Geopotential Height (contours, units: dagpm) and 850 hPa Wind Field (wind barbs, units: m/s) at 12 UTC on July 2, 2025

Figure 2  Accumulated Precipitation from June 30 to July 4, 2025 (unit: mm)

Figure 3  Maximum Wind Gusts (shaded, unit: m/s) in 24 Hours on July 2, 2025

Author: Hu Yingying                                 Reviewer: Niu Ruoyun 

English reviewer:Wang Yi                                   Issue approver:Dai Kan