COLUMN: Weather Wise

Sunset over the River Ure at Roecliffe, near Boroughbridge. (S)
Sunset over the River Ure at Roecliffe, near Boroughbridge. (S)

Gordon Currie looks back at the weather phenomena of 2012 and looks at prospects for the week ahead:

There was something grippingly symbolic within the picture of the flooded willow garth near Hutton Conyers in the fading daylight of December’s final day.

Across the expanse of water towards the River Ure, a virtual mirror of crimson light reflected from the sunset betrayed the flotsam of broken branches, the images of a broken year, 2012.

The black, lifeless fronds of the willow trees, stippled against the deepening twilight, engaged a similar theme and reminded me of the poet Shelley, with his description of “bare ruined choirs, where late the sweet birds sang”.

Yet, beyond the trees, the reassurance of brighter days hung like a celestial orb across the western sunset sky.

The entire scene bore pictorial witness to the epic weather history which has been so infamously carved through the months of 2012, and which will surely occupy a unique position in the annals of time.

Yet, witnessing this scene as an amateur meteorologist, I knew that we were already being confronted with a major turn in the weather which was about to co-incide with the turn of the year.

The final potentially soaking cold front had just departed on the final day of the year – the 23rd day of December rainfall, and the jet-stream was already moving into its normal position after nine consecutive excessively wet months ... welcome, 2013, things can only get better!

It will come as no surprise to find that December made its significant contribution to 2012’s record rainfall figure with 127.7mm rainfall (5.1in), the highest total for any December since my records began in 1946. The month’s mean temperature was 37.7F. (3.3C), some 2.0F (1.6C) below the long term normal.

Reviewing the weather, the month began with maritime polar and Arctic air streams which dominated the first fortnight. Clear skies, sunny days, but very cold nights accounted for the lowest maxima of 34F (1C) on the 1st, and 36F (2C) on the 2nd, 6th, and 11th days.

Lowest night minima during the opening two weeks were mainly between 27 - 24 F (-3 to -4C), with the lowest reading, 22F (5.5C) recorded at sunrise on the 6th.

On the 12th and 13th, winds fell light to calm, leading to the stagnation of very cold air close to the ground surface. This effect, coupled with increasing atmospheric moisture, led to the formation of one of our typical frost-fogs along the Ure valley and in the Vale of York which proved very slow to lift. Consequently, daily maxima of 30F and 29F (-1.6C) occurred on the 12th and 13th respectively.

On the 14th, a very intense Atlantic frontal system moved north-eastwards over England but its movement was slowed down considerably by a strong surge of high pressure (over 1050 millibars) across north-western Russia. Rainfall amounted to 14mm (0.55 in) marking the first heavy rainfall of a successive series until the end of the year, leaving only two completely dry days between the 14th and 31st. The wettest days were: the 20th, 20.7mm (0.82in); and 24th, 24.1mm (0.96in).

Reviewing the statistics for the year 2012, rainfall figures dominate the picture, having a 12-month total figure of 1081.7mm (43.24in). This beats my previous annual record of 959.9mm (38.39in) registered in 2000, and compares with 606.2 mm (24.24in) in 2011 and 614.7mm (24.58in) in 2010.

The long-term annual average for my records is 637mm (25.5in). Before examining some of the causes and features of 2012’s weather, readers may be interested to know that the longest dry spells were recorded as follows: January 5-17 (12 consecutive rainless days), March 18 - 31 (13 days), and May 19 - 30 (11 days). Mention could also be made of February 10 - 26, with only 0.12in over 16 days, and September 1 - 10, completely rainless.

Events at the end of March, featuring the withdrawal of the strong high pressure system westwards into the mid-Atlantic (rather than the normal eastwards movement), opened the door to polar and Arctic air steams which pushed the jet-stream far southwards from its normal position, creating a precipitous fall of temperature from 68F (20C) on March 28 to 28F (-2C) on April 5.

This sudden change caused a complete dysfunctional pattern of our weather as depressions tracked successively either to the south of our region, or right across the north of England, resulting in a whole series of intense three-day rainfall events, listed as follows : June 7 - 9, 50 mm (2.00in) as a depression moved over Lancashire and Yorkshire to be centred off the East Coast; June 21- 23, 55.7 mm(2.22in), with low-moving across Yorkshire, having thunderstorms embedded in its circulation; July 4 - 6, 54.6 mm (2.18in), caused by a stationary front with waves running along its length; September 23 - 25, 95.2mm (3.80in), low tracking across England, with remnants of tropical storm Nedine in its circulation; November 24 - 26, 62mm (2.48 in) caused by two lows moving across the south, with their stationary fronts arcing across Yorkshire.

Was it really the worst summer for farmers? Very debatable, for the memories of the oldest farming generation, with visions of their floating corn stooks down flooded rivers in 1946, and combine harvesters bogged up to their axels in the harvest fields of 1954 and 1956. From a sheer day-to-day “workability” standpoint, the summers of the 1950s have already been compared with that of 2012. Rain fell on 23 days in both Augusts, 1954 and 1956. To be fair, comparisons and perspectives tend to become distorted with the long passage of time. It was not entirely doom and gloom in 2012, recollecting the gloriously cloudless and warm days in the second-half of May during the first cuts of silage (warmest days of the year, 79F, or 26.5C) and the providential ten very dry and breezy days in early September for the harvest. No doubt many of our older farmers may shrug their shoulders with their familiar adage of experience, “we’ve seen it all before!”.

My final acknowledgement of 2012’s weather highlights the renewed plethora of wisdom and words from the advocates of climate change, who delude themselves into their profound certainties and their transparencies of vision upon our warming future and impending disasters. They overlook one subtle difference, – the past is built upon certainties, the future nothing more than probabilities. The skill of mastering any exactness with future trends is far from anyone’s grasp – it is merely supposition.

Let us just settle for some recompense from Mother Nature in 2013!

PROSPECTS FOR THE WEEK AHEAD

With high pressure areas building over Europe and around the British Isles, Atlantic cyclonic activity will be considerably weakened with mild conditions beginning to fade. Easterly or south-easterly winds will tend to filter colder continental air across the British Isles in the coming days.

Mainly dry, apart from a few wintry showers on one or two weak fronts. Generally very little rainfall expected. Mist or fog at times. Temperatures falling slowly, 4 - 6C (39 -43F), with night frosts becoming sharper, down to 23F (-5C).