Much lower than average pressure to the north (-8 hPahPa A Hectopascal is the SI unit of pressure and identical to the Millibar), and higher than average pressure in the central Atlantic (+5 hPa), produced a W’NW flow and lower than average temperatures across IONAIONA Islands Of North Atlantic. Yes I know there's an island called Iona, but this is so I don't have to use the term 'British Isles' when referring to the whole of Ireland and the UK..