Marine heatwaves hit Mediterranean as eastern US braces for storms

Above-normal sea surface temperatures are being recorded across much of the Mediterranean, especially in eastern areas. While sea surface temperatures are near or slightly below average along the eastern coasts of Iberia, across the eastern Mediterranean temperatures remain high, with deviations of 3C-4C above normal for this time of the year, particularly in the Aegean Sea.

The Black Sea is experiencing very large temperature anomalies of 4C-6C above normal. The duration and intensity of these abnormal temperatures classify these events as marine heatwaves, in categories 2 and 3. Such heatwaves can influence the marine ecosystems of a region, but also have an impact on weather patterns, with the relatively warm waters providing extra energy to the weather systems.

On the other side of the Atlantic, a pre-Thanksgiving storm may bring hazardous weather conditions across areas of the eastern US, including heavy rain and thunderstorms as well as some gusty winds and snow. Thanksgiving Day itself is expected to be predominantly dry with sunny conditions across much of the country, but another storm is likely to bring sleet and snow to many areas of north-western states, including Utah, Nevada, Idaho and Wyoming, through Thursday and Friday, followed by a significant drop in temperatures into the weekend.

Meanwhile, more than 3,000 towns and cities in Brazil were put on red alert for heat last week, with Rio de Janeiro recording the highest ever November temperature of 42.5C last Sunday. Temperatures have been widely reaching the mid- to high-30s, but peaking in the low 40s, affecting more than 100 million people in Brazil and Paraguay.

The effects of this sustained heat have been felt across the Pantanal tropical wetlands in the Central-West region of Brazil, where there have been more than 2,000 fires in the first two weeks of November. In comparison, there were just 57 fires in the same region last year. Taylor Swift postponed her concert in Rio de Janeiro on Sunday due to the temperatures. It followed the death of a fan before Friday night’s show, which local authorities and politicians have suggested was linked to the extreme heat, which reached 39.1C in Rio on Friday.

This heat is forecast to continue across parts of South America this week as daily temperatures remain at least 5C above average. In addition to extreme temperatures, Brazil’s National Institute of Meteorology has issued heavy rain and storm warnings for intense rainfall, gusty winds, and potential flooding across the south-east during the early part of this week.