MET Service Explains Weather Forecasts

In response to public concern about the accuracy of weather predictions from the Meteorological Service of Jamaica, Director, Evan Thompson, has indicated that misunderstandings of forecasting terminology, rather than errors in the forecasting, are often the root of the problem.

He pointed out that while there are genuine instances where forecasters get it wrong, “there are sometimes misunderstandings of the entire forecast”.

Mr. Thompson was the guest speaker at a hybrid meeting of the Rotary Club of St. Andrew North, held at the JN Conference Services Centre in Kingston, on Monday (August 11).

He explained that with predictions of rain, for instance, citizens tend to simply take note of the area or parishes for which rain is forecast, but not other important classifications involved.

“Sometimes when you say isolated showers, people don’t see it any different from widespread or numerous showers, but they are completely different things,” Mr. Thompson pointed out.

He outlined that ‘isolated showers’ means only one-tenth of the area in question is likely to receive rainfall, while ‘widely scattered’ sees this probability going up to about 20 to 30 per cent.

“But when we say scattered, then it may be a little over 30 [per cent], and then we say widespread, now we’re talking about 40 to 50 per cent… and then when we say numerous, it’s a different thing, because now it’s almost like you’re going to get it almost everywhere… maybe 80 per cent of the area will have showers,” the Director outlined.

He emphasised that it is important for citizens to understand the wording of the forecasts to fully appreciate the information provided.

Mr. Thompson added that another common issue that leads to perceived inaccuracy in forecasts is citizens not following the predictions for the area in which they reside.

“We sometimes pinpoint the major towns and cities… but you might not be living in a major town or city. So, sometimes the forecast might not give you a good snapshot of exactly where you are. So, you have to kind of take it with an understanding that you’re in the ballpark area, so prepare yourself for this kind of activity,” he said.