Long-lasting UK marine heatwave likely to reach extreme levels next week - Met Office

Surface waters in Northwest European seas are currently experiencing moderate to severe marine heatwave conditions, with widespread areas of “strong” (Category 2) conditions and some locations reaching “severe” (Category 3).

This means that waters have reached temperatures usually expected in August and are on average 2°C warmer than usual, locally reaching +4-5°C anomalies offshore parts of the Welsh and English coasts.

These elevated sea-surface temperatures have developed rapidly partially because of last week’s record-breaking atmospheric heatwave and could intensify further in the coming week when settled and sunny weather is likely to return.

The provisional UK June temperature record was exceeded on three consecutive days last week. Typically lagging inland weather by around 3-5 days, sea-surface temperatures have responded quickly, with the Bay of Biscay reaching unprecedented values for June.

While this exceptional land heatwave was primarily driven by atmospheric conditions, the surrounding marine environment played a role in prolonging warmth on land as the heatwave declined, when light winds favoured the movement of warmer-than-average marine air inland.