
Strong winds and flooding spread across New Zealand last week, with a state of emergency declared in Christchurch, after the country was battered by a destructive area of low pressure. A red warning, the highest warning level, was issued by the MetService (the national meteorological service).
The area of low pressure quickly deepened in the Tasman Sea off the west coast of New Zealand and travelled eastwards, with the centre of low pressure moving across the northern island and creating very strong winds, particularly through the Cook Strait, the body of water that separates the two islands. The wind direction was a south-easterly to southerly, which caused the winds to strengthen as they were funnelled between the islands.
New Zealand’s capital, Wellington, recorded some of the strongest winds, with gusts exceeding 90mph. Flooding was also an issue, especially for the southern island as the winds brought in moist air from the sea which rapidly rose over the Southern Alps producing heavy rain. More than 100mm of rain fell in less than 12 hours across some eastern areas and the local government called a state of emergency in Christchurch, the largest city in the southern island, as rivers burst their banks and roads closed. Snow warnings were issued across mountainous areas, with some parts experiencing more than 50cm of snowfall in 24 hours. Large swell was produced by the area of low pressure, with waves of almost 6 metres through the Cook Strait.
Meanwhile, large areas of Europe are experiencing above-average temperatures, particularly in central and north-west regions. Temperatures in Vienna in Austria are expected to soar above 30C through the weekend, more than 10C above the average. Some cities in Germany and France are also expected to experience temperatures of about 30C.
The high temperatures are a result of a low-pressure system over Portugal that will continue to drive a warm southerly flow across Europe. However, the high temperatures are not forecast to last, as a cooler northerly flow develops across Europe into next week. This will cause temperatures to drop to about 10C below average, with places that were reaching high 20C this week struggling to get maximum temperatures much above low teens.