An early taste of spring is on the way for millions across northern and western Europe this week. Temperatures could climb close to a near record-breaking 20C (68F) in parts of Belgium, Germany, Luxembourg and the Netherlands, with south-western France approaching 25C on Wednesday.

The warmth is being driven by a highly amplified synoptic pattern, featuring a region of low pressure over the Atlantic and strong high pressure over central Europe. The setup will allow exceptionally mild air to spread across much of the continent, with temperatures in some places rising to 10-15C above the seasonal average.

The dominance of high pressure will also bring largely dry conditions, offering welcome relief to areas that have endured an exceptionally wet February. However, Portugal and north-western Spain are likely to face further spells of heavy rain.

Across the Atlantic, conditions will be markedly different in the south-eastern US. States including Alabama, Florida, Georgia and South Carolina could face temperatures 10-15C below normal for this time of year, bringing widespread cold and frosty nights.

In Miami, temperatures could plunge to about 7C on Tuesday morning – cold enough for iguanas to drop from trees. The reptiles become “cold-stunned” in low temperatures, leaving them immobilised and prone to falling. Iguanas are an invasive species in Florida, and residents have previously been encouraged by state wildlife officials to humanely capture and hand over incapacitated reptiles during such cold snaps.

The chill across the south-east is linked to a rapidly intensifying area of low pressure tracking up the east coast. Such powerful storms are commonly known as Nor’easters, reflecting the strong north-easterly winds they bring to states such as Connecticut, Massachusetts and New Jersey.

The National Weather Service has issued blizzard warnings in connection with this storm. Snow began falling on Sunday night and was forecast to continue through Monday, with a total of 60cm (25in) expected.

New York City and Boston are likely to experience the worst disruption, with up to 50cm of snow possible and 50mph winds. The storm comes towards the end of a notably cold and snowy winter across much of the US – potentially the snowiest since 2018.