New Zealand: Severe weather forecast across parts of eastern and northern North Island through at least Nov. 21

Severe weather is forecast across parts of eastern and northern North Island through at least Nov. 21. A slow-moving low-pressure system east of Northland is gradually weakening, bringing heavy rainfall to affected areas.

As of Nov. 20, the New Zealand National Meteorological Service (MetService) has issued the following weather warnings:

• Orange Heavy Rain Warning (middle level on a three-tier scale): Tairawhiti/Gisborne from Tolaga Bay northwards, Ruahine Range, and the inland ranges of Hawke's Bay. Further rainfall of up tp 12 cm (4.7 inches) is forecast.

• Yellow Heavy Rain Watch: Tairawhiti/Gisborne south of Tolaga Bay, Wairarapa from about Carterton northwards, the rest of Tararua District, and the rest of Hawke's Bay.

• Yellow Severe Thunderstorm Watch: Auckland, Bay of Plenty, Coromandel Peninsula, and Waikato.

Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rain has saturated the soil.

Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Disruptions to electricity and telecommunications services are likely where significant flooding or landslides impact utility networks.

Floodwaters and debris flows will likely render some bridges or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces will likely cause hazardous driving conditions on regional highways. Authorities are likely to temporarily close some low-lying routes that become inundated by floodwaters. Flight delays and cancellations at airports are probable.

Localized business disruptions are likely in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.