When we have a hot spell such as we experienced over recent days, I have always secretly hoped that the highest temperatures would be recorded in an appropriately named Irish weather station, such as Newport Furnace in Co Mayo or Ovens in Co Cork. However, Shannon Airport took the prize on Tuesday last with a maximum temperature of 30.6 degrees, thus for the second day in a row breaking the almost 30-year record of the hottest day in May previously held by Ardfert in Kerry. But what was remarkable about last week was that these temperatures did not just break previous records by the usual 0.1 or so degrees but demolished them by a full 2 degrees or more. Something exceptional was occurring.

The mechanics of the hot spell were fairly similar to previous events. A large stationary anticyclone was facilitating a plume of hot air reaching Ireland from the near continent and ultimately from North Africa. The heat dome this descending air produced effectively trapped heat close to the surface rather like putting a lid on a saucepan being heated from below. But other ingredients were also apparent. Somewhat unusually, the air higher up in the atmosphere was coming in for a time from a rather cold source, namely the western Atlantic and even eastern Canada. As this made its way across the Atlantic it was forced to descend under the European anticyclone, compressing and heating it up, and ultimately adding further to the heat dome at the surface.

Extreme temperatures such as we had last week cannot be seen to be other than a consequence of Ireland’s warming climate. Although........

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