COLUMN: Weather Wise with Gordon Currie

The golden stems of a field of wheat as harvest time gets under way. (James Hardisty)
The golden stems of a field of wheat as harvest time gets under way. (James Hardisty)
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Gordon takes a look back at the weather throughout September and gives prospects for the week ahead.

Remembrance opens many doors

To scenes of summer past,

And pageants of a season

Which seemed too good to last;

Now we share the legacies

Of harvest salutation

To look across the landscape

And realise salvation

Lies in fruitfulness and promise

Of the land’s immortal text –

Sustain all life in Nature

From one year to the next!

On looking up a little piece of farming history from my farming and weather diary written on October 25 1960, I find a very contrasting illustration of how the arable world of farming has moved forward, a great contrast between the 1960 picture and the present day conditions of an exceedingly helpful early autumn season so far recorded: “The farmer who, by virtue of his tactful manoeuvres and calculated risks with regard to recent adverse weather conditions, has managed to harrow in the last of his autumn sowings by the last week of October, may well credit himself with having successfully achieved another operational gamble in this year of exceptional abnormalities.” The second half of 1960 proved to be exceedingly wet, with October being one of the wettest on my records.

Returning to the present day and the weather of the past month, September has certainly distinguished itself for spells of dry weather and warm sunshine, punctuated with the type of rainfall which promoted an ideal workability for the progressive work on the land. The month was slightly warmer than average, with mean daily maximum temperatures of 64.1 F. (17.8 C.), night minimum, 49.3 F. (9.6 C.), giving an overall mean figure of 56.7 F. (13.7 C.). This compares with last year’s mean of 55.8 F. (13.2 C.).

It may be interesting to note that our warmest September’s on my records were in 2006, 62.5 F. (16.9 C.), 1949, 61.2 F. (16.2 C.) and 1947, 59 F. (15.0 C.). The total rainfall (up till the 29th) was 57.3 millimetres (2.29 in.) compared with the long term average of 55 mm. (2.20 ins.). Since the start of the new century we have had several drier than average Septembers, notably 2004, 13.3 mm. (0.53 in.), 2007, 22.4 mm. (0.89 in.) and 2009, 19.6 mm. (0.78 in.).

Taking a closer look at some of the weather events last month, the persistent warmth and dryness of late August, intensified during the early days of September, following a brief incursion of a strong, cool north-westerly air stream on September 1. Pressure rose across the southern parts of England and the neighbouring Continent, transporting very warm but rather humid air from France.

Early morning fogs, the first of the season, cleared quickly, with temperatures peaking at 75 F. (24 C.) on the 4th and the 5th. Then followed a dramatic change, as a weak and quite innocuous looking cold front began to make progress south-eastwards over the British Isles on the 5th.

This front was virtually rainless for much of its passage, though it did mark a discontinuity line between the high temperatures to the east of the front and the much cooler westerlies behind it. When it heats up the Continental land reached the east coast and the North Sea, it became energised and fuelled by the high humidity of the Continental air mass, drawing in huge quantities of moisture into its system. Total rainfall for 24 hours ending 9am on the 7th amounted to 40 mm. (1. 60 inches) which proved to be the heaviest downpour of the month.

Temperatures fell from maximum of 75 F. (24 C.) on the 5th, to 54 F (12 C.) on the 6th. Much cooler conditions with westerly winds bringing maritime polar air from fairly high latitudes of the North Atlantic followed for several days, giving slight falls of showery rain and daily maxima slightly below normal, especially on the 17th and 18th, 54 F. (12 C.). Here, towards the Vale of York, there were some notably cold nights under clear skies, with the winds dropping to calm around sunrise. Lowest night minima of the month were 36 F. (2 C.) on the 8th, with the first slight ground frost of the season, 39 F. (4 C.) on the 9th, and 38 F. (3.5 C.) 0n the 19th.

Towards the 20th, a strong warm front was moving towards the British Isles, bringing very moist, warm air from sub-tropical latitudes of the Atlantic. This change established warmer-than-average conditions for the remainder of the month.

Some days were rather cloudy, due to the high atmospheric moisture content in the “warm sector” conditions behind the warm front, but this state of affairs did not last very long, as the pressure rose and the airmass dried out very gradually. 70 F. (21 F.) was attained on the 22nd and 27th, with brilliant sunshine once again to end the month. By the 29th, the edge was removed from the warmth slightly by stronger easterly winds. This was due to the high pressure system becoming anchored over the Scandinavian countries, feeding slightly cooler, drier air to England. Interestingly perhaps, became the comparison of the pressure pattern (high over Scandinavia, low over the Bay of Biscay) with the pressure charts of March and April this year!

Thankfully, the summer heats up the Continental land mass, - and just to set your minds at rest, there is no reason whatsoever to imagine that this comparison of pressure patterns bears any forthcoming relationship towards the chances of a severe winter!

PROSPECTS FOR THE WEEK AHEAD

High pressure is likely to remain fairly dominant across most of Europe in the coming week, with low pressure centres likely to be slow moving in the south western and western approaches to the British Isles. A few fronts may manage to penetrate across England as they spiral around the low pressure to the west, but basically, it looks as though the Atlantic systems will be baulked by the European high pressure.

A good deal a dry and fairly mild weather, with overnight mists and fogs giving way to spells of sunshine on most days. A few showery outbreaks of rain are likely to affect our region as the week goes on, but at the moment, these risks appear to be small. Temperatures generally close to seasonal normal with southerly or easterly winds.