WEATHER WATCH: How convection helps control weather patterns
Convection is a method of heat distribution that occurs within the atmosphere as well as in bodies of water. Convection contributes substantially to the other physical processes that are fundamental in causing weather phenomena.
Air that is in immediate contact with a surface that is warmer than itself warms by conduction. This causes it to become less dense and buoyant.
Colder air from above or alongside moves in to take its place and, after warming, rises and is replaced. Hence, either a horizontal or a vertical circulation develops, always with colder dense air replacing the warm ascending air.
Water uses upside-down-convection to distribute heat within itself. When the top layer of water cools, it becomes heavier than the water below and sinks beneath it. In turn that warmer water cools and sinks as a consequence.
Fresh water is at its most dense at 4.0C (39.2F) and starts to freeze at 0C (32F). Because of upside-down-convection it can take water a long time to cool to 4.0C throughout its depth. However, once it has fallen to that temperature, water becomes less dense if it gets colder, with the result that surface ice develops.
August 2024 was Wick’s coolest since that of 2021. However, perusal of the town’s historic record for mean air temperature for a series of Augusts commencing from 1910 avouched that it is currently the 25th warmest.
In terms of precipitation, August 2024 was the driest since that of 2021, and is presently the 39th least wet in a series of Augusts stretching back to 1910.
Wick’s mean air temperature for summer 2024 was 12.67C (54.81F). The long-term average for summer in terms of the averaging period 1991-2020 is 12.57C (54.63F).
The town’s rainfall total for summer 2024 was 180.20mm (7.09 inches). The long-term average quantity for summer is 186.52mm (7.34 inches).
Wick’s mean air temperature for August 2024 was 13.58C (56.44F). The long-term average in terms of the averaging period 1991-2020 is 13.33C (55.99F).
The royal burgh’s average daytime maximum air temperature for the month was 16.61C (61.90F). The long-term average is currently 16.29C (61.32F).
Highest maximum was 23.4C (74.1F), recorded on August 5. A maximum of 20.6C (69.1F), noted on August 27, was also noteworthy for the town.
Lowest maximum was 14.2C (57.6F), logged on August 16.
Wick’s average overnight minimum air temperature for August 2024 was 10.54C (50.97F). The long-term average for the month in terms of the current 30-year averaging period is 10.36C (50.64F). Highest minimum was 13.9C (57.0F), recorded on August 5.
Lowest minimum air temperature was 6.7C (44.1F), observed on August 21.
The lowest temperature recorded at 5cm over the grass was 4.7C (40.5F), on August 4 and 31 respectively.
Precipitation was measurable on 29 dates. The total for the month was 55.6mm (2.19 inches), or 79.7 per cent of the long-term average for August. Wettest day was August 3. The amount logged during the 24 hours commencing 9am (GMT), was 8.4mm (0.33 of an inch).
There were no “days of gale” recorded during the month. However, wind velocities reached or surpassed gale force 8 (39.0mph/33.9knots) on five dates.
The windiest day of the month was August 13, when a force 6 south-westerly wind gusted up to 46.0 mph/40.0 knots, gale force 8 on the Beaufort scale.
