A LINK between heat waves over central and western Europe and temperatures in the north Atlantic has been discovered by scientists from Southampton’s National Oceanography Centre.

This finding may be an important factor for the prediction of hot spells over Europe, since it suggests the Atlantic Ocean could have a role as a precursor.

The lead authors of new paper, Dr’s Aurélie Duchez and Joël Hirschi, from the NOC, said: “Our study suggests the forecast of European heat waves can potentially be improved by looking out for early warning signs in the ocean.”

The North Atlantic and Europe experienced two contrasting weather events during the summer of 2015: while record cold surface ocean temperature anomalies were observed in the north-east Atlantic, large parts of Europe were affected by an extreme heat wave.

The cold Atlantic conditions preceded the European summer heat wave.

Extreme heat loss from the ocean to the atmosphere during the winters 2013-14 and 2014-15 led to the north-east Atlantic cooling by one –to- two degrees Celsius below the normal spring temperature. Importantly, this cold anomaly extended to 700m below the surface.

The cold anomaly coincided with a warmer ocean anomaly further south, off Morocco.

By early June 2015 both the warm and cold anomalies over the North Atlantic became most pronounced. In the second half of June the atmosphere adopted a circulation pattern that led to the development of the European heat wave. In particular, the Jet Stream shifted southwards over the North Atlantic, closely following the warm and cold anomalies that had previously developed.

This link is not unique to 2015. All major European heat waves since 1980 were preceded by anomalously cold May temperatures in the NE Atlantic.

This suggests that there may be an oceanic precursor to Central and Western European heat waves.