7 Day Weather Forecast Is It Worth The Paper Its Written On

Weather forecasting is becoming more accurate. I don’t think there is much doubt about that. With the introduction of ever more sophisticated technology, both computerised and satellite, any weather professional can be more confident than ever about his ability to forecast…but only to a point.

Thanks to the chaotic nature of our climate and atmosphere a long range forecast is still not something you would bet your house on. Most weather forecasts are accurate to within two or three days, but then the percentages drop away sharply.

As the weather is global in nature it makes sense that global cooperation is required to help the forecasters. Most countries now have some form of national weather service with a remit to produce accurate forecasts for a couple of days ahead. However the measurements and forecasts observed in every county give an important contribution to the worldwide network and allow more data to be fed into the computer models.

There are three national superpowers that are particularly involved in global forecasting. In England there is the British Meteorological Office, in the US the American National Weather Centre and for Europe the ECMWF (European Centre for Medium Range Weather Forecasts) also located in England. The ECMWF concentrates on forecasts from 1 to 10 days, and covers 17 countries. This organisation spends a large amount of time collecting and analysing data from around the world and is generally considered a leader in medium term forecasting.

There is also the WMO (World Meteorological Organisation) which is an agency operated for and behalf of the United Nations with over 170 member countries. This organisation was established in 1951 and is tasked with improving weather observations, and allowing an optimum flow of information, around the world.

Observations and data for weather forecasting come from many different sources. Around 13,000 land stations, 7,500 ships, commercial airliners and satellites are also all pouring data into the computer models around the world which in turn churn out weather predictions from a few minutes (e.g. Tornadoes) to hundreds of years (e.g. global warming).

So, with all this information available, with all this hardware and software, and an incredible network of observations from the oceans, the atmosphere and from space is a 7 day forecast worth the paper it is written on? Well, maybe…you see it all depends on where you are in the world. Some climates rarely change, such as the Sahara desert and a forecast of this area will be pretty straightforward the majority of the time with perhaps just some tweaking of the high and low temperatures.

Other areas of the world however are much more changeable and harder to predict. The British Isles for instance lying on the western edge of Europe, with the jet stream taking aim from across the Atlantic and the Gulf Stream conveying warm air to our shores, is much more difficult to measure. A slight change in the direction of a depression mid-atlantic can have a marked effect on the local weather. The same is true of course for cyclones and hurricanes, and tornadoes and dust storms.
And that for me is the great thing about the weather. It is so unpredictable and chaotic. Yes, the forecasts are becoming ever more sophisticated and accurate but they will never be 100% accurate, and I wouldn’t have it any other way. So is a 7 day weather forecast worth the paper it is written on? Probably, but with so many caveats you wouldn’t put a bet on it.