Weather pundit says 'marine layer' kept temperatures down in Caithness despite the sunshine
Wick-based weather columnist Keith Banks noted that despite high temperatures across Scotland this week, areas around the Caithness coast were affected by a phenomenon called 'marine layer'.
Keith said that Scotland enjoyed its warmest day of the year on Thursday and that “Caithness did not miss out” with temperatures climbing into the high teens Celsius.
“However, during the first 10 days of April, Wick, together with other parts exposed to the North Sea and despite the unbroken sunshine, was plagued by a phenomenon called a 'marine layer' that depressed the daytime temperatures,” he said.
“Because the strong temperature inversion that had existed in the atmosphere that was responsible for causing this effect had weakened as the high declined, this layer of cool, moist air trapped beneath it had dissipated by Thursday afternoon, allowing a westerly breeze to introduce warmer air. As a result, the mercury hit a seasonally warm 17.7C (63.9F), eclipsing the town's previous best temperature for the year so far when 17.0C (62.6F) was recorded on March 31.”
The average daily maximum air temperature for Wick in April is 10C (50F). Wick's highest temperature for any April since 1910 is 20.2C (68.4F), recorded on April 28, 1987.
“April has been outstandingly dry so far. The rainfall total for Wick this month up to 6am (GMT) on Friday, April 11, was a negligible 0.2mm (0.01 of an inch). Wick's average rainfall total for April is currently 47.5mm (1.87 inches).”
The protracted spell of settled and very dry weather is the consequence of a weather feature meteorologists call an 'Omega high', he added.
“Since it developed at the beginning of April, this large high has been almost stationary near or over the UK and has caused the jet stream to steer the rain-bearing fronts, and strong winds associated with the Atlantic depressions far away from the British Isles.
“This type of weather pattern is called 'blocking'. The high is now in decline and retreating south-eastwards over the continent. This change will allow low pressure and attendant fronts to gradually encroach from the Atlantic by the end of the weekend.
“However, temperatures will remain warm on Friday and Saturday, perhaps reaching highs of 17C-18C or even 19C in any areas of sunshine across favoured inland locations of Caithness.”
