Even hi-tech modern meteorology cannot get predictions 100pc correct – but it can help farmers assess the relative risk of their vital work in the fields. CHRIS HILL spoke to one of East Anglia's best-known weathermen.
Of all the variables dictating farming success or failure, the weather will always be the most unpredictable.
So far, 2018 has been a case in point. The severe shock of ice and snow from the Beast from the East in February was followed by a soggy March, a mini-heatwave in April, and then more downpours at the start of this week.
All of which proves the value of accurate forecasts to help livestock and arable farmers plan decisions which could have expensive, or environmental, repercussions if their timing is wrong.
But for Jim Bacon, the former TV weatherman who is now managing director of Weatherquest, based at the Enterprise Centre at the UEA in Norwich, the goal is not to deliver a guaranteed forecast – it is to provide the data to assess the 'relative risk' of operations like spraying chemicals, or irrigating a field.
'The atmosphere is so complex you will never get it 100pc right,' he said. 'It is about conveying the element of risk. Some people choose to have insurance, some don't – and it is the same with this.
'The width of a thunderstorm might only be a kilometre across. So when one tracks across the landscape it is drawing a pencil line across the landscape that could make one field very wet and leave a field on the other side of the farm completely dry.
'To get a forecast based on the nearest grid point is fine if you don't need to know what is going on around you. If you can predict a shower correctly within 4km from 36 hours ahead, that's pretty good. But it is no good to a farmer with a tank of spray being washed into a field drain.
'When farmers ring up they ask about spraying they are asking questions to decide in relative risk terms if it is a gamble to spray the crop today. If it is, we will tell them, but if they say they have got to get it done in the next three days, we could tell them which day has the lowest risk.
'We won't make the weather go away, but we can give them the best chance of managing that risk and getting the result they want.'
Mr Bacon said a key modern tool is known as 'ensemble forecasting', where instead of making a single forecast of the most likely weather, a set of forecasts is produced from varied starting points to give an indication of the range of possible weather permutations – which could highlight unexpected risks.
'On one occasion we looked at 50 runs of a model to see how temperature was changing,' he said. 'I was speaking at a farming conference. It was about seven degrees and I said after tonight you will get temperatures dropping to around zero in all the models. So it might be a bit of a frost, but not enough to damage sugar beet.
'But the thing that stood out was that one of these runs of the model came up with what we call an 'outlier'. It showed a temperature of -16 degrees in eight days time, and in a winter which so far had no frost.
'The way I feel about modern meteorology is you can use these ensembles to show where the risk lies in a particular operation. You might need to know if you've got enough oil for your grain house heaters, or enough tarpaulins for your sugar beet, or should you get a haulier in to carry it away to the factory before the temperature drops. Because, when this gets out, everyone will want the hauliers.
'It won't always happen like this, but it actually got to -13 degrees, and I assume the sensible ones in the audience would have taken action. But those that didn't will have regretted it.
'All of this happens because models have got better and computers have got faster, and it has paid dividends in people's ability to manage the risk from negative weather. It is these sort of things that can make a very big difference in terms of the bottom line.'
Weatherquest advises almost 200 farming businesses, including large estates, co-operatives, seed companies and research bodies.
AN 'AVERAGE' WINTER
Despite the seemingly wild swings in weather since the start of the year, Mr Bacon said the winter of 2017/18 actually ended up being statistically average for both temperatures and rainfall.
'The newspapers got a bit carried away with the Beast from the East,' he said. 'You would need to go back a few decades to get periods where it was always like that in the winter, not least the winter of 1962-63. It was more the duration of it than the amount of snow. Everything was frozen from Boxing Day to March. Stuff was frozen in the ground so to get beet and mangels out you would need a pick-axe.
'If someone says to you in five years' time: What do you remember of the winter of 2017/18? You would remember that snow, but overall the figures for December through to the end of February show it was an average winter for rainfall and average temperatures. But we all know it was extremely significant for a short period because everything, including agriculture, was severely affected by the weather.'
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